Mycobacterium tuberculosis mmaA3 mutations conferring resistance to isoniazid

Accession ARO:3004929
CARD Short NameMtub_mmaA3_INH
DefinitionMutations that occur in mmaA3 that result in or contribute to antibiotic resistance to isoniazid.
AMR Gene Familyisoniazid resistant mmaA3
Drug Classisoniazid-like antibiotic
Resistance Mechanismantibiotic target alteration
Classification9 ontology terms | Show
Parent Term(s)2 ontology terms | Show
+ isoniazid resistant mmaA3 [AMR Gene Family]
+ confers_resistance_to_antibiotic isoniazid [Antibiotic]

Goossens SN, et al. 2020. Clin Microbiol Rev 34(1): Mechanisms of Drug-Induced Tolerance in Mycobacterium tuberculosis. (PMID 33055230)

Tudó G, et al. 2010. Future Med Chem 2(8):1371-83 Examining the basis of isoniazid tolerance in nonreplicating Mycobacterium tuberculosis using transcriptional profiling. (PMID 21426023)


Prevalence of Mycobacterium tuberculosis mmaA3 mutations conferring resistance to isoniazid among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI or IslandViewer for 413 important pathogens (see methodological details and complete list of analyzed pathogens). Values reflect percentage of genomes, plasmids, genome islands, or whole-genome shotgun assemblies that have at least one hit to the AMR detection model. Default view includes percentages calculated based on Perfect plus Strict RGI hits. Select the checkbox to view percentages based on only Perfect matches to AMR reference sequences curated in CARD (note: this excludes resistance via mutation as references in protein variant models are often wild-type, sensitive sequences).

Prevalence: protein variant model

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGSNCBI GI
No prevalence data

Detection Models

Model Type: protein variant model

Model Definition: Protein Variant Models (PVM) perform a similar search as Protein Homolog Models (PHM), i.e. detect protein sequences based on their similarity to a curated reference sequence, but secondarily screen query sequences for curated sets of mutations to differentiate them from antibiotic susceptible wild-type alleles. PVMs are designed to detect AMR acquired via mutation of house-keeping genes or antibiotic targets, e.g. a mutated gyrase resistant to aminocoumarin antibiotics. PVMs include a protein reference sequence (often from antibiotic susceptible wild-type alleles), a curated bit-score cut-off, and mapped resistance variants. Mapped resistance variants may include any or all of single point mutations, insertions, or deletions curated from the scientific literature. A Strict RGI match has a BLASTP bit-score above the curated BLASTP cutoff value and contains at least one curated mutation from amongst the mapped resistance variants, while a Loose RGI match has a bit-score less than the curated BLASTP bit-score cut-off but still contains at least one curated mutation from amongst the mapped resistance variants.

Bit-score Cut-off (blastP): 550


  • discovered in clinical, agricultural, or environmental isolates

  • discovered via laboratory selection experiments

  • ReSeqTB

Published Variants:

PMID in progress (TB): G98D


Indeterminate ConfidenceG98D

>gb|CCP43386.1|-|Mycobacterium tuberculosis mmaA3 mutations conferring resistance to isoniazid [Mycobacterium tuberculosis H37Rv]

>gb|AL123456.3|-|737268-738149|Mycobacterium tuberculosis mmaA3 mutations conferring resistance to isoniazid [Mycobacterium tuberculosis H37Rv]