Table 2.
Mutation Patterns in Genes Involved in Resistance to First- and Second-Line Drugs
| Drug | Gene | Mutation Patterns in Drug Resistant Isolatesa | Mutation Patterns in Drug Susceptible Isolatesa |
|---|---|---|---|
| RIF | rpoB | D516V; H526D; H526R; H526Y; S531L; L511P & H526Q; H526D & M736T; L511R & D516Y; Q513-F514ins; S531L & L635P |
I572F |
| INH | katG | W149R; S315T; S315N; W477L & A479P; Gene deletion |
G560S |
| inhA gene and promoter region | c-15t; c-15t and S94A | ||
| katG + inhA | F720S + c-15t | ||
| EMB | embB | M306I; M306L; M306V; D328Y; F330S; F330V | D354A; G406A; Q497R; Q497L |
| STM | rpsL | K43R; K88R; K88T | |
| rrs-F1b | a514c; c905a | ||
| Ofx | gyrA | G88A, A90V, S91P, D94A, D94G, | |
| gyrB | G407Cc, S413Ac, A432Pc, G512Rc, K600Tc, I601Lc, A644Dc | ||
| gyrA + gyrB | D94G + A644Da | D7Na + A644Dc, H87Q & D94G + A644Dc |
|
| SLID (Am, Km or Cm) | rrs-F2d | a1401g, a1401g, c1489t | g1177a, 1204 ins a |
| PZAe | pncA gene and promoter region | a-11g; V7G; D8E; L19P; L35P; T47P; H71Y; Y103C; S104R; V131G; A171E; A171V; partial pncA gene deletion | |
Notes: aDrug susceptibility patterns were obtained using the BACTEC MGIT 960 method used according to the standard critical antibiotic concentrations recommended by the WHO: RIF (1.0 µg/mL), INH (0.1 µg/mL), EMB (5.0 µg/mL), STM (0.1 µg/mL), Ofx (2.0 μg/mL); Am (1.0 μg/mL); Km (2.5 μg/mL), Cm (2.5 μg/mL); bSequencing targeting Loops 530 and 915 of the rrs gene; cMutation outside quinolone resistance-determining regions; dSequencing targeting the 1400–1500 regions of rrs gene; eSusceptibility to PZA is not available.
Abbreviations: Am, amikacin; Cm, capreomycin; EMB, ethambutol; INH, isoniazid; Km, kanamycin; Ofx, ofloxacin; PZA, pyrazinamide; RIF, rifampicin; SLID, second-line injectable agents; STM, streptomycin.