Table 3.
Patterns of gene mutations in resistant MTB isolates using the GenoType MTBDRsl assay
| Gene | Band | Gene region/mutation | OFX resistant (n = 77), n (%) | OFX monoresistant (n = 31), n (%) | KM resistant (n = 15), n/N | KM monoresistant (n = 2), n/N | EMB resistant (n = 87), n (%) | EMB monoresistant (n = 44), n (%) | XDR-TB (n = 6), n/N |
|---|---|---|---|---|---|---|---|---|---|
| gyrA | WT1 | 85–90 | 77 (100.0) | 31 (100.0) | 15/15 | 2/2 | 87 (100.0) | 44 (100.0) | 6/6 |
| WT2 | 89–93 | 65 (84.4) | 29 (93.5) | 14/15 | 2/2 | 78 (89.7) | 44 (100.0) | 6/6 | |
| WT3 | 92–97 | 43 (55.8) | 19 (61.3) | 8/15 | 2/2 | 67 (77.01) | 44 (100.0) | 1/6 | |
| MUT1 | A90V | 44 (57.1) | 20 (64.5) | 6/15 | 0 | 21 (24.1) | 0 | 3/6 | |
| MUT2 | S91P | 1 (1.3) | 1 (3.2) | 6/15 | 0 | 0 | 0 | 0 | |
| MUT3A | D94A | 15 (19.5) | 5 (1.61) | 1/15 | 0 | 9 (10.3) | 0 | 0 | |
| MUT3B | D94N/Y | 6 (7.8) | 6 (1.94) | 0 | 0 | 0 | 0 | 0 | |
| MUT3C | D94G | 25 (32.5) | 11 (3.55) | 5/15 | 0 | 12 (13.8) | 0 | 4/6 | |
| MUT3D | D94H | 2 (2.6) | 1 (3.2) | 1/15 | 0 | 1 (1.1) | 0 | 1/6 | |
| rrs | WT1 | 1401–1402 | 70 (90.9) | 31 (100.0) | 7/15 | 2/2 | 83 (95.4) | 44 (100.0) | 2/6 |
| WT2 | 1484 | 76 (98.7) | 31 (100.0) | 14/15 | 2/2 | 86 (98.9) | 44 (100.0) | 5/6 | |
| MUT1 | A1401G, C1402T | 11 (14.3) | 0 | 15/15 | 2/2 | 8 (9.2) | 0 | 6/6 | |
| MUT2 | G1484T | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| embB | WT1 | 306 | 38 (49.4) | 31 (100.0) | 8/15 | 2/2 | 4 (4.6) | 2 (4.5) | 2/6 |
| MUT1A | M306I | 19 (24.7) | 0 | 5/15 | 0 | 32 (36.8) | 11 (25.0) | 2/6 | |
| MUT1B | M306V | 19 (24.7) | 0 | 3/15 | 0 | 44 (50.6) | 25 (56.8) | 2/6 |
OFX: Ofloxacin; KM: Kanamycin; EMB: Ethambutol; XDR-TB: Extensively drug-resistant tuberculosis; MTB: Mycobacterium tuberculosis.