Table 2.
Gene mutations associated with MICs overlapping the critical concentration of each antituberculosis drug21
| Mutation | Isolates | Susceptible isolates | Observed MIC range (mg/L) | ||
|---|---|---|---|---|---|
| Rifampicin | |||||
| rpoB | Asp435Val | 68 | 9 | 0·5 to ≥20 | |
| rpoB | His445Leu | 6 | 4 | 1·0 to 4·0 | |
| Kanamycin | |||||
| eis | −10 G→A | 18 | 4 | 0·63 to 12·5 | |
| eis | −12 C→T | 121 | 13 | 1·25 to 12·5 | |
| eis | −37 G→T | 11 | 2 | 2·5 to 12·5 | |
| eis | −14 C→T | 5 | 1 | 1·25 to ≥25 | |
| Amikacin | |||||
| eis | −14 C→T | 12 | 8 | 0·5 to 4·0 | |
| Capreomycin | |||||
| rrs | 1401 A→G | 25 | 6 | 1·25 to ≥12·5 | |
| Moxifloxacin | |||||
| gyrA | Ala90Val | 50 | 9 | 0·25 to 4·0 | |
| Levofloxacin | |||||
| gyrA | Ala90Val | 27 | 3 | 0·75 to 8·0 | |
| Ethambutol | |||||
| embB | Met306Ile | 79 | 54 | 1·0 to 16·0 | |
| embB | Met306Val | 65 | 16 | 2·0 to 16·0 | |
| embB | Gln497Arg | 7* | 5 | 4·0 to 8·0 | |
| Pyrazinamide | |||||
| pncA | Leu19Pro | 2 | 1 | 100 to 200 | |
| pncA | Asp63Ala | 3 | 1 | 100 to 200 | |
| pncA | Val7Ala | 2* | 1 | 50 to 200 | |
| pncA | Val180Ala | 4* | 2 | 100 to >400 | |
Critical concentrations for these drugs are: rifampicin (1·0 mg/L), isoniazid (0·1 mg/L), kanamycin (2·5 mg/L), amikacin (1·0 mg/L), capreomycin (2·5 mg/L), moxifloxacin (0·25 mg/L), levofloxacin (1·0 mg/L), ethambutol (4·0 mg/L), and pyrazinamide (100 mg/L). MIC=minimum inhibitory concentration.
*
Clonal populations (difference of less than 12 single nucleotide polymorphisms between isolates).