Table 5.
Mutations found in resistance-related genes for the World Health Organization (WHO) group C second-line drugs in in 35 rifampicin-resistant Mycobacterium tuberculosis strains [3,26,28,31,32,33].
| Drug | Resistance Phenotype (No. of Strains) | Resistance Genotype | MIC (µg/mL) | Total | ||
|---|---|---|---|---|---|---|
| Gene | Mutations | No. of Strains | ||||
| PTO | Resistant (19) | ethA | Thr314Ile | 1 | 5 | 19/19 |
| Ala341Glu | 1 | 5 | ||||
| Trp21 del (freq: 10.32%) | 1 | 5 | ||||
| T1361 del | 1 | 10 | ||||
| Gln254Pro | 1 | 10 | ||||
| 1 | 5 | |||||
| ethA/fabG1-ups/inhA | Trp116 del (freq: 59.63%)/−27 to −38 del/Ser94Ala (freq: 20.69%) | 1 | 20 | |||
| ethA-ups | T-11G | 1 | 10 | |||
| fabG1-inhA | C-15T | 2 | 20 | |||
| 3 | 10 | |||||
| 3 | 5 | |||||
| inhA/fabG1-inhA/ndh | Ala239Val/C-15T/399A ins | 1 | 20 | |||
| fabG1/fabG1-inhA | Leu203Leu (freq: 57.5%)/C-15T (freq: 50.9%) | 1 | 20 | |||
| inhA | Ser94Ala | 1 | 20 | |||
| Susceptible (16) | ethA | Gln254Pro | 2 | 0.6 | 2/16 | |
| DCS | Resistant (9) | cycA | Pro188Ala | 1 | 32 | 1/9 |
| ald, ddlA, alr, cycA | WT | 6 | 32 | |||
| WT | 2 | 64 | ||||
| Susceptible (26) | ald | GC432 ins | 2 | 16 | 10/26 | |
| Cyc333Trp (freq: 10.9%) | 1 | 16 | ||||
| Ala340Ser (freq: 5.0%) | 1 | 16 | ||||
| ddlA | 2A ins (freq: 7.3%) | 1 | 4 | |||
| Arg264Gly (freq: 6.5%)/Val260Gly (freq: 6.0%) | 1 | 16 | ||||
| Gln293Glu (freq: 5.0%) | 1 | 8 | ||||
| Thr322Ser (freq: 5.1%) | 1 | 2 | ||||
| alr | Leu113Arg | 1 | 16 | |||
| cycA | Leu21His (freq: 5.3%) | 1 | 8 | |||
| CFZ | Resistant (5) | Rv1979c | 1014A del | 1 | 2 | 1/5 |
| Rv0678, Rv1979c, pepQ | WT | 3 | 2 | |||
| WT | 1 | 4 | ||||
| Susceptible (30) | Rv0678 | Gly87Arg | 1 | 1 | 3/30 | |
| Rv1979c | Asn297Ser | 1 | 1 | |||
| pepQ | Ala87Gly (freq: 12.79%) | 1 | 1 | |||
| LZD | Susceptible (35) | rrl | C1537T | 1 | 0.25 | 4/35 |
| C1331T | 1 | 0.12 | ||||
| rplC | Ala72Thr | 2 | 0.5 | |||
WHO: World Health Organization, MIC: minimum inhibitory concentration, PTO: prothionamide, DCS: D-cycloserine, CFZ: clofazimine, LZD: linezolid, ups: upstream, del: deletion, WT: wild type, ins: insertion, freq: frequency, A; adenine, T; thymine, G; guanine, C; cytosine.