Abstract
Bedaquiline, clofazimine and linezolid are pertinent drugs for drug-resistant tuberculosis. Drug-resistant mutants provide insight into important resistance acquisition mechanisms. Methods for in vitro Mycobacterium tuberculosis mutant generation are poorly described.
Induction (serial passaging) and spontaneous (adapted Luria-Delbruck assay) approaches using M. tuberculosis ATCC reference strains (one fully-susceptible, four unique mono-resistant) were performed.
Mutant MIC values were confirmed (MGIT960) and resultant RAVs compared between approaches and to a catalog of previously published RAVs. Mutant MIC values showed a 3-4-fold (induced) and a 1-4-fold (spontaneous) increase compared to baseline. The pyrazinamide-resistant strain had higher baseline MIC values and acquired resistance (>= 4-fold) in fewer passages than other strains (induction approach) for bedaquiline. Previously described and novel RAVs in atpE (8 vs. 1) and rv0678 (4 vs. 12) genes were identified in bedaquiline- and clofazimine-resistant mutants. No rv1979c and rv2535c RAVs were identified. Previously described RAVs were identified in TIC and rrl genes for linezolid-resistant mutants.
Both approaches successfully led to in vitro mutants with novel RAVs being described in atpE and rv0678 genes. It was observed that pre-existing resistance may influence mutant phenotypic and genotypic characteristics and warrants further attention.
Original language | English |
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Pages (from-to) | 1-9 |
Number of pages | 9 |
Journal | Journal of Microbiological Methods |
Volume | 153 |
DOIs | |
Publication status | Published - Oct 2018 |
Keywords
- M. tuberculosis
- Mutants
- Bedaquiline
- Clofazimine
- In vitro
- DRUG-RESISTANCE
- ATP SYNTHASE
- PYRAZINAMIDE RESISTANCE
- ACQUIRED-RESISTANCE
- MUTATION-RATE
- OXAZOLIDINONE
- PERSPECTIVE
- MECHANISMS
- EMERGENCE
- TMC207