Disease Information

General Information of the Disease (ID: DIS00004)

• Name: Mycobacterial diseases
• ICD: ICD-11: 1B2Z

Type(s) of Resistant Mechanism of This Disease

  ADTT: Aberration of the Drug's Therapeutic Target

  DISM: Drug Inactivation by Structure Modification

  EADR: Epigenetic Alteration of DNA, RNA or Protein

  IDUE: Irregularity in Drug Uptake and Drug Efflux

  UAPP: Unusual Activation of Pro-survival Pathway

Drug Resistance Data Categorized by Drug

Approved Drug(s) 29 drug(s) in total

6-N-ethyl-netilmicin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: 6-N-ethyl-netilmicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: 6-N-ethyl-netilmicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Amikacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Amikacin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 160; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Aminodeoxykanamycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Aminodeoxykanamycin
• Molecule Alteration: Expression; Inherence
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: Thirty-four environmental and clinical isolates belonging to theM. fortuitumcomplex were chosen for the present study. The MICs of gentamicin varied, ranging from 2 to 16mg/ml. Crude extracts of all 34 strains were shown to have AAC activity. Acetylation of gentamicin, tobramycin, and kanamycins A and B was found for all the strains, showing a substrate profile consistent with the presence of an AAC(3) activity. Environmental isolateM. fortuitumFC1k was chosen for further studies because of its high level of AAC activity and the level of resistance to gentamicin (MIC, 16mg/ml).

Amoxicillin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Beta-lactamase (BLA) [4]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Amoxicillin
• Molecule Alteration: Expression; Inherence
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli strain HB101; 634468
• In Vitro Model: Escherichia coli strain MC1061; 1211845
• In Vitro Model: Escherichia coli strain XL1-Blu9; 562
• In Vitro Model: Mycolicibacterium fortuitum strain D316; 1766
• In Vitro Model: Mycolicibacterium fortuitum strain FC1; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc^155; 246196
• Experiment for Molecule Alteration: SDS-polyacrylamide gel assay
• Experiment for Drug Resistance: MIC assay
• Mechanism Description: The gene encoding a class A (t-lactamase was cloned from a natural Isolate of Mycobacterium fortuitum {blaF) and from a high-level amoxicillJn-resistant mutant that produces large amounts of p-lactamase (blaF*).

Ampicillin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Ampicillin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 158; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Clarithromycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: 23S ribosomal RNA methyltransferase Erm (ERM39) [5]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Clarithromycin
• Molecule Alteration: Missense mutation; Putative initiation codon GTG>CTG
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium peregrinum ATCC14467; 43304
• Experiment for Molecule Alteration: DNA sequencing assay
• Experiment for Drug Resistance: Mueller-Hinton (MH) broth assay
• Mechanism Description: The erm genes are a diverse collection of methylases that add one or two methyl groups to the adenine at position 2058 (Escherichia coli numbering) of the 23S rRNA; this modification impairs the binding of macrolides to ribosomes, and thus reduces the inhibitory activity of these agents.

Clindamycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: 23S ribosomal RNA methyltransferase Erm (ERM39) [5]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Clindamycin
• Molecule Alteration: Missense mutation; Putative initiation codon GTG>CTG
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium peregrinum ATCC14467; 43304
• Experiment for Molecule Alteration: DNA sequencing assay
• Experiment for Drug Resistance: Mueller-Hinton (MH) broth assay
• Mechanism Description: The erm genes are a diverse collection of methylases that add one or two methyl groups to the adenine at position 2058 (Escherichia coli numbering) of the 23S rRNA; this modification impairs the binding of macrolides to ribosomes, and thus reduces the inhibitory activity of these agents.

Delamanid

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Unusual Activation of Pro-survival Pathway (UAPP)

Key Molecule: FO synthase (FBIC) [6]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Delamanid
• Molecule Alteration: Missense mutation; p.V318I
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Streptococcus pneumoniae strain; 1313
• Experiment for Molecule Alteration: qRT-PCR
• Experiment for Drug Resistance: alamarBlue assay
• Mechanism Description: Mutation in codon 318 of the fbiC gene was identified as the sole mutation related to DMD resistance.

Dibekacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Dibekacin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Dibekacin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin.

Erythromycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: 23S ribosomal RNA methyltransferase Erm (ERM39) [5]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Erythromycin
• Molecule Alteration: Missense mutation; Putative initiation codon GTG>CTG
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium peregrinum ATCC14467; 43304
• Experiment for Molecule Alteration: DNA sequencing assay
• Experiment for Drug Resistance: Mueller-Hinton (MH) broth assay
• Mechanism Description: The erm genes are a diverse collection of methylases that add one or two methyl groups to the adenine at position 2058 (Escherichia coli numbering) of the 23S rRNA; this modification impairs the binding of macrolides to ribosomes, and thus reduces the inhibitory activity of these agents.

Gatifloxacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: DNA gyrase subunit A (GYRA) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.G280A (c.D94N)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit A (GYRA) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.A281G (c.D94G)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit A (GYRA) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.G280T (c.D94Y)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit A (GYRA) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.G262T (c.G88C)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit B (GYRB) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.A1495G (c.N499D)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit B (GYRB) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.C1497A (c.N499K)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit B (GYRB) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.C1497G (c.N499K)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Key Molecule: DNA gyrase subunit B (GYRB) [7]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Gatifloxacin
• Molecule Alteration: Missense mutation; p.A1503C (c.E501D)
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: STK11 KO cells; Fetal kidney; Homo sapiens (Human); CVCL_B3IE
• Experiment for Molecule Alteration: Whole-genome sequencing assay
• Mechanism Description: Mutations in the gyrA and gyrB genes are the main mechanisms of Gatifloxacin (GAT) resistance.

Gentamicin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Gentamicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Gentamicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Gentamicin B

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Gentamicin B
• Molecule Alteration: Expression; Inherence
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: Thirty-four environmental and clinical isolates belonging to theM. fortuitumcomplex were chosen for the present study. The MICs of gentamicin varied, ranging from 2 to 16mg/ml. Crude extracts of all 34 strains were shown to have AAC activity. Acetylation of gentamicin, tobramycin, and kanamycins A and B was found for all the strains, showing a substrate profile consistent with the presence of an AAC(3) activity. Environmental isolateM. fortuitumFC1k was chosen for further studies because of its high level of AAC activity and the level of resistance to gentamicin (MIC, 16mg/ml).

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Gentamicin B
• Molecule Alteration: Expression; Acquired
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin.

Gentamicin C

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Gentamicin C
• Molecule Alteration: Expression; Inherence
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: Thirty-four environmental and clinical isolates belonging to theM. fortuitumcomplex were chosen for the present study. The MICs of gentamicin varied, ranging from 2 to 16mg/ml. Crude extracts of all 34 strains were shown to have AAC activity. Acetylation of gentamicin, tobramycin, and kanamycins A and B was found for all the strains, showing a substrate profile consistent with the presence of an AAC(3) activity. Environmental isolateM. fortuitumFC1k was chosen for further studies because of its high level of AAC activity and the level of resistance to gentamicin (MIC, 16mg/ml).

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Gentamicin C
• Molecule Alteration: Expression; Acquired
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin.

Ibudilast

Drug Sensitivity Data Categorized by Their Corresponding Mechanisms

Unusual Activation of Pro-survival Pathway (UAPP)

Key Molecule: Toll like receptor 4 (TLR4) [8]

• Sensitive Disease: Bone infection [ICD-11: 1B2Z.9]
• Sensitive Drug: Ibudilast
• Molecule Alteration: Function; Inhibition
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vivo Model: Femoral defect model; Male C57BL/6NCrlBltw mouse model; Mus musculus
• Experiment for Drug Resistance: Serum Osteocalcin and CTX1 Assay; Micro-CT Bone Imaging
• Mechanism Description: LPS inhibited osteogenic factor-induced MC3T3-E1 cell differentiation, alkaline phosphatase (ALP) levels, calcium deposition, and osteopontin secretion and increased the activity of osteoclast-associated molecules, including cathepsin K and tartrate-resistant acid phosphatase in vitro. Ibudilast blocked the LPS-induced inhibition of osteoblast activation and activation of osteoclast in vitro and attenuated LPS-induced delayed callus bone formation in vivo.

Isoniazid

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: Enoyl-[acyl-carrier-protein] reductase [NADH] (INHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S94A
• Wild Type Structure: Method: X-ray diffraction; Resolution: 1.40 Å; PDB: 4TRO
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 1.90 Å; PDB: 4DTI

RMSD: 0.13; TM score: 0.99951; Amino acid change: S94A

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Enoyl-[acyl-carrier-protein] reductase [NADH] (INHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G141E
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Enoyl-[acyl-carrier-protein] reductase [NADH] (INHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.I194T
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315T
• Wild Type Structure: Method: X-ray diffraction; Resolution: 2.00 Å; PDB: 2CCA
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 2.10 Å; PDB: 2CCD

RMSD: 0.24; TM score: 0.99934; Amino acid change: S315T

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315N
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.A312P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.A264V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.N660D
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.L147P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.C20R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.T308P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.T275A
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.D142G
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S211G
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.M126I
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.W91R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.S315G
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G490S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.V581G
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.A110V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G466R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G279V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.L436P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.N508D
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.P92S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G125S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.Q127P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.V431A
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G490S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.Q461P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.E607A
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.H417Q
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G111S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.G33V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Catalase-peroxidase (KATG) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Missense mutation; p.W191R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Isoniazid
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 161; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Unusual Activation of Pro-survival Pathway (UAPP)

Key Molecule: NAD-dependent protein deacylase Sir2 (SIR2) [10]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli; 668369
• In Vitro Model: Mycobacterium smegmatis mc2155; 246196
• Experiment for Molecule Alteration: Quantitative Real-Time PCR
• Experiment for Drug Resistance: Colony forming units determination assay
• Mechanism Description: MSMEG_5175 regulates diverse cellular processes resulting in an increase in INH resistance in mycobacteria. Overexpression of MSMEG_5175 results in up-regulation of 34 proteins and down-regulation of 72 proteins, which involve in diverse cellular processes including metabolic activation, transcription and translation, antioxidant, and DNA repair. Down-regulation of catalase peroxidase (katG) expression in both mRNA and protein levels were observed in mc(2)155-MS5175 strain, suggesting that a decrease in cellular NAD content and down-regulation of katG expression contribute to the higher resistance to INH in mc(2)155-MS5175.

Key Molecule: D-inositol 3-phosphate glycosyltransferase (MSHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Non-synonymous mutation; p.F355S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: D-inositol 3-phosphate glycosyltransferase (MSHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Isoniazid
• Molecule Alteration: Non-synonymous mutation; p.N111S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Kanamycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Kanamycin
• Molecule Alteration: Expression; Inherence
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: Thirty-four environmental and clinical isolates belonging to theM. fortuitumcomplex were chosen for the present study. The MICs of gentamicin varied, ranging from 2 to 16mg/ml. Crude extracts of all 34 strains were shown to have AAC activity. Acetylation of gentamicin, tobramycin, and kanamycins A and B was found for all the strains, showing a substrate profile consistent with the presence of an AAC(3) activity. Environmental isolateM. fortuitumFC1k was chosen for further studies because of its high level of AAC activity and the level of resistance to gentamicin (MIC, 16mg/ml).

Levofloxacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Epigenetic Alteration of DNA, RNA or Protein (EADR)

Key Molecule: DNA topoisomerase (ATP-hydrolyzing) (PARC) [11]

• Resistant Disease: Mycoplasma hominis genital infection [ICD-11: 1B2Z.7]
• Resistant Drug: Levofloxacin
• Molecule Alteration: Missense mutation; p.K134R
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycoplasma hominis ATCC 23114(PG21); 347256
• In Vitro Model: Mycoplasma hominis isolate; 2098
• Experiment for Molecule Alteration: Whole genome sequence assay
• Mechanism Description: The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Key Molecule: DNA topoisomerase (ATP-hydrolyzing) (PARC) [11]

• Resistant Disease: Mycoplasma hominis mycoplasma infection [ICD-11: 1B2Z.4]
• Resistant Drug: Levofloxacin
• Molecule Alteration: Missense mutation; p.K134R
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycoplasma hominis ATCC 23114(PG21); 347256
• In Vitro Model: Mycoplasma hominis isolate; 2098
• Experiment for Molecule Alteration: Whole genome sequence assay
• Mechanism Description: The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Netilmicin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Netilmicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Netilmicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin.

Norfloxacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Norfloxacin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 155; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Ofloxacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Epigenetic Alteration of DNA, RNA or Protein (EADR)

Key Molecule: DNA topoisomerase (ATP-hydrolyzing) (PARC) [11]

• Resistant Disease: Mycoplasma hominis genital infection [ICD-11: 1B2Z.7]
• Resistant Drug: Ofloxacin
• Molecule Alteration: Missense mutation; p.K134R
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycoplasma hominis ATCC 23114(PG21); 347256
• In Vitro Model: Mycoplasma hominis isolate; 2098
• Experiment for Molecule Alteration: Whole genome sequence assay
• Mechanism Description: The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Key Molecule: DNA topoisomerase (ATP-hydrolyzing) (PARC) [11]

• Resistant Disease: Mycoplasma hominis mycoplasma infection [ICD-11: 1B2Z.4]
• Resistant Drug: Ofloxacin
• Molecule Alteration: Missense mutation; p.K134R
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycoplasma hominis ATCC 23114(PG21); 347256
• In Vitro Model: Mycoplasma hominis isolate; 2098
• Experiment for Molecule Alteration: Whole genome sequence assay
• Mechanism Description: The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Ofloxacin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 156; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Oxacillin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Oxacillin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 159; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Prothionamide

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: Enoyl-[acyl-carrier-protein] reductase [NADH] (INHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.S94A
• Wild Type Structure: Method: X-ray diffraction; Resolution: 1.40 Å; PDB: 4TRO
• Mutant Type Structure: Method: X-ray diffraction; Resolution: 1.90 Å; PDB: 4DTI

RMSD: 0.13; TM score: 0.99951; Amino acid change: S94A

• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Enoyl-[acyl-carrier-protein] reductase [NADH] (INHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.G141E
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: Enoyl-[acyl-carrier-protein] reductase [NADH] (INHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.I194T
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Drug Inactivation by Structure Modification (DISM)

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.P28S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.L35R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.G42D
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.D56Y
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.D58G
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.W69C
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.H102P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.C137R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.Y141N
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.T186P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.T189R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.Q246P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.S266R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.R279E
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.S329P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.P334A
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.A341V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.N345K
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.A352E
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.M372R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.C403Y
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.F480S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.I161V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.G324R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.Q254P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.S266R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.S266R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.M373T
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.L267V
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.R239Q
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.S266R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.Q165P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.Q246R
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.L446P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.V179F
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.A395D
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.Q254P
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.G43S
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: FAD-containing monooxygenase EthA (ETHA) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.W69C
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: HTH-type transcriptional regulator EthR (ETHR) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.V152M
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Key Molecule: HTH-type transcriptional regulator EthR (ETHR) [9]

• Resistant Disease: Mycolicibacterium smegmatis infection [ICD-11: 1B2Z.6]
• Resistant Drug: Prothionamide
• Molecule Alteration: Missense mutation; p.R216C
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Mycobacterium tuberculosis strain H37Rv ATCC27294 T; 83332
• Experiment for Molecule Alteration: Sequencing analysis
• Experiment for Drug Resistance: In vitro drug susceptibility testing
• Mechanism Description: Notably, isoniazid is activated by the enzyme catalase-peroxidase, KatG, encoded by katG, whereas prothionamide is activated by the flavin monoxygenase, EthA, encoded by ethA. Mutations in katG and ethA are associated with individual isoniazid and prothionamide/ethionamide resistance, respectively. The ndh gene coding for NADH dehydrogenase, Ndh, was first identified as a new mechanism for INHR in Mycobacterium smegmatis. The mutations in ndh gene cause defects in the oxidation of NADH to NAD, which results in NADH accumulation and NAD depletion. The increased level of NADH inhibits the binding of isoniazid-NAD adduct to the active site of the InhA enzyme, which disturbs the regulation of enzyme activity and may cause co-resistance to isoniazid and prothionamide. EthR, a member of the TetR/CamR family, is a repressor of ethA. EthR regulates the transcription of ethA by coordinated octamerization on a 55-bp operator situated in the ethA-R intergenic region. Impeding EthR function leads to enhanced mycobacterial sensitivity to prothionamide, whereas mutations in ethR encoding a negative transcriptional regulator of the expression of EthA lead to prothionamide resistance. Finally, MshA, a member of the glycosyltransferase family, is a key enzyme involved in mycothiol biosynthesis in M. tuberculosis. Mutations in mshA coding MshA have been proposed to create a disturbance in prothionamide/ethionamide activation.

Quinupristin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: 23S ribosomal RNA methyltransferase Erm (ERM39) [5]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Quinupristin
• Molecule Alteration: Missense mutation; Putative initiation codon GTG>CTG
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium peregrinum ATCC14467; 43304
• Experiment for Molecule Alteration: DNA sequencing assay
• Experiment for Drug Resistance: Mueller-Hinton (MH) broth assay
• Mechanism Description: The erm genes are a diverse collection of methylases that add one or two methyl groups to the adenine at position 2058 (Escherichia coli numbering) of the 23S rRNA; this modification impairs the binding of macrolides to ribosomes, and thus reduces the inhibitory activity of these agents.

Rifampin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: Multidrug efflux pump Tap (TAP) [12], [13]

• Resistant Disease: Mycobacterium tuberculosis infection [ICD-11: 1B2Z.5]
• Resistant Drug: Rifampin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium tuberculosis H37Rv; 83332
• In Vitro Model: Mycobacterium tuberculosis ICC154; 1773
• Experiment for Molecule Alteration: Whole genome sequence assay
• Experiment for Drug Resistance: MIC assay
• Mechanism Description: One mechanism proposed for drug resistance in Mycobacterium tuberculosis (MTB) is by efflux of the drugs by membrane located pumps.Mycobacterium tuberculosis isolate with a distinct genomic identity overexpresses a tap-like efflux pump,which confers resistance to Rifampin and Ofloxacin.

Key Molecule: Multidrug efflux pump Tap (TAP) [12], [13]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Rifampin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium tuberculosis H37Rv; 83332
• In Vitro Model: Mycobacterium tuberculosis ICC154; 1773
• Experiment for Molecule Alteration: Whole genome sequence assay
• Experiment for Drug Resistance: MIC assay
• Mechanism Description: One mechanism proposed for drug resistance in Mycobacterium tuberculosis (MTB) is by efflux of the drugs by membrane located pumps.Mycobacterium tuberculosis isolate with a distinct genomic identity overexpresses a tap-like efflux pump,which confers resistance to Rifampin and Ofloxacin.

Rifaximin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Ribonuclease PH (RPH) [14], [15], [16]

• Resistant Disease: MycoBacterial infection [ICD-11: 1B2Z.1]
• Resistant Drug: Rifaximin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli TOP10; 83333
• In Vitro Model: Bacillus cereus RPH-Bc; 1396
• In Vitro Model: Escherichia coli Rosetta(DE3) pLysS; 866768
• In Vitro Model: L. monocytogenes; 1639
• Experiment for Molecule Alteration: Whole genome sequence assay
• Experiment for Drug Resistance: MIC assay
• Mechanism Description: RIF phosphotransferase (rph) led to the identification of a new resistance gene and associated enzyme responsible for inactivating rifamycin antibiotics by phosphorylation.

Sparfloxacin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Epigenetic Alteration of DNA, RNA or Protein (EADR)

Key Molecule: DNA topoisomerase (ATP-hydrolyzing) (PARC) [11]

• Resistant Disease: Mycoplasma hominis genital infection [ICD-11: 1B2Z.7]
• Resistant Drug: Sparfloxacin
• Molecule Alteration: Missense mutation; p.K134R
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycoplasma hominis ATCC 23114(PG21); 347256
• In Vitro Model: Mycoplasma hominis isolate; 2098
• Experiment for Molecule Alteration: Whole genome sequence assay
• Mechanism Description: The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Key Molecule: DNA topoisomerase (ATP-hydrolyzing) (PARC) [11]

• Resistant Disease: Mycoplasma hominis mycoplasma infection [ICD-11: 1B2Z.4]
• Resistant Drug: Sparfloxacin
• Molecule Alteration: Missense mutation; p.K134R
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycoplasma hominis ATCC 23114(PG21); 347256
• In Vitro Model: Mycoplasma hominis isolate; 2098
• Experiment for Molecule Alteration: Whole genome sequence assay
• Mechanism Description: The single amino acid mutation in ParC of MH may relate to the resistance to OFX and LVX and the high-level resistance to fluoroquinolones for MH is associated with mutations in both DNA gyrase and the ParC subunit of topoisomerase IV.

Irregularity in Drug Uptake and Drug Efflux (IDUE)

Key Molecule: P-type ATPase zinc transporter Rv3270 [2]

• Resistant Disease: Bone infection [ICD-11: 1B2Z.9]
• Resistant Drug: Sparfloxacin
• Molecule Alteration: Expression; Up-regulation
• Experimental Note: Revealed Based on the Cell Line Data
• In Vitro Model: E. coli XL1-Blue; 562
• In Vitro Model: E. coli CS109; 562
• In Vitro Model: M. smegmatis MC2 157; 1772
• Experiment for Molecule Alteration: Gene expression analysis
• Experiment for Drug Resistance: Antimicrobial susceptibility assay; Intracellular drug accumulation activity assay
• Mechanism Description: Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

Spiramycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Aberration of the Drug's Therapeutic Target (ADTT)

Key Molecule: 23S ribosomal RNA methyltransferase Erm (ERM39) [5]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Spiramycin
• Molecule Alteration: Missense mutation; Putative initiation codon GTG>CTG
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Mycobacterium peregrinum ATCC14467; 43304
• Experiment for Molecule Alteration: DNA sequencing assay
• Experiment for Drug Resistance: Mueller-Hinton (MH) broth assay
• Mechanism Description: The erm genes are a diverse collection of methylases that add one or two methyl groups to the adenine at position 2058 (Escherichia coli numbering) of the 23S rRNA; this modification impairs the binding of macrolides to ribosomes, and thus reduces the inhibitory activity of these agents.

Tobramycin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [1]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Tobramycin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Discovered Using In-vivo Testing Model
• In Vitro Model: Escherichia coli strain DH5a; 668369
• In Vitro Model: Mycolicibacterium smegmatis strain EP10; 1772
• In Vitro Model: Mycolicibacterium smegmatis strain mc2155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Agar macrodilution assay
• Mechanism Description: The introduction of a plasmid-located copy of either the aac (2')-Ib or the aac (2')-Id genes into M. smegmatis mc2155 produces an increase in the level of resistance over those values observed in M. smegmatis mc2155. However, the introduction of the plasmid-located aac (2') Ic gene did not lead to an increase in the MICs. In this experiment, an increase of at least two dilutions in the MIC values over those observed in M. smegmatismc2155 with the vector pSUM36 has been assumed to be due to the increase in the activity of the AAC (2') enzyme. The MICs for the 2'-ethylnetilmicin do not change since this aminoglycoside is not a substrate of the AAC (2') enzyme.

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium fortuitum infection [ICD-11: 1B2Z.2]
• Resistant Drug: Tobramycin
• Molecule Alteration: Expression; Inherence
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: Thirty-four environmental and clinical isolates belonging to theM. fortuitumcomplex were chosen for the present study. The MICs of gentamicin varied, ranging from 2 to 16mg/ml. Crude extracts of all 34 strains were shown to have AAC activity. Acetylation of gentamicin, tobramycin, and kanamycins A and B was found for all the strains, showing a substrate profile consistent with the presence of an AAC(3) activity. Environmental isolateM. fortuitumFC1k was chosen for further studies because of its high level of AAC activity and the level of resistance to gentamicin (MIC, 16mg/ml).

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: Tobramycin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin.

Investigative Drug(s) 1 drug(s) in total

6'-N-Ethylnetilmicin

Drug Resistance Data Categorized by Their Corresponding Mechanisms

Drug Inactivation by Structure Modification (DISM)

Key Molecule: Aminoglycoside 2'-N-acetyltransferase (A2NA) [3]

• Resistant Disease: Mycobacterium smegmatis infection [ICD-11: 1B2Z.3]
• Resistant Drug: 6'-N-Ethylnetilmicin
• Molecule Alteration: Expression; Acquired
• Experimental Note: Identified from the Human Clinical Data
• In Vitro Model: Escherichia coli XL1-Blue; 562
• In Vitro Model: Streptomyces lividans strain 1326; 1200984
• In Vitro Model: Mycolicibacterium fortuitum strain FC1k; 1766
• In Vitro Model: Mycolicibacterium smegmatis strain mc2 155; 246196
• Experiment for Molecule Alteration: Southern blot hybridizations assay
• Experiment for Drug Resistance: Twofold dilution of antibiotics assay
• Mechanism Description: The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin.

References

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