Table 2.
Fitness cost and compensatory mechanisms in specific genetic mutations involved in evolution of resistance to Mycobacterium tuberculosis
| Gene mutation(s) | Fitness cost | Compensatory mechanism |
|---|---|---|
| inhA | Reduced biosynthesis of fatty acids | Secondary mutation in inhA promoter |
| inhA promoter | No | No |
| katG | Reduced protection against oxidative damage | Overexpression of ahpC by mutation in its promoter |
| rpoB | Decreased efficiency of DNS transcription | Secondary mutation in rpoA, rpoC or rpoB |
| rpsL & rrs | Impaired ribosome performance | Unknown |
| pncA | Unknown | Unknown |
| embB | Reduced cell wall biosynthesis efficiency | Secondary mutation in embABC operon |
| gyrA & gyrB | Reduced DNA supercoiling, reduced DNS replication | Secondary mutation in gyrA or gyrB |
| Eis | No | No |