TABLE 1.
Sequence polymorphisms and POA and PZA broth and agar MICs of POA-resistant M. tuberculosis strains
| M. tuberculosis H37Rv straina | Mutations |
POAb |
PZAb |
|||
|---|---|---|---|---|---|---|
| clpC1c | Other genes | MIC50 (mM) in broth | MICd (mM) in agar | S/Re | MICd (mM) in agar | |
| Wild-type | —f | — | 1.5 | 1 | S | 2 |
| POAr 1 (panD1)g I | — | panD: Δ380A | 6.0 | >4 | R | >4 |
| POAr 11 (clpC1-1) 1, I | G-10Ch | — | 5.5 | >4 | R | >4 |
| POAr 12 (clpC1-2) 2, II | C262G/Leu88Val | mmpL7: T534G/Asp178Glu | 5.5 | >4 | R | >4 |
| POAr 13 (clpC1-3) 3, I | G296A/Gly99Asp | — | 6.0 | >4 | R | >4 |
| POAr 14 (clpC1-3) 4, I | G296A/Gly99Asp | — | 6.0 | >4 | R | >4 |
| POAr 15 (clpC1-4) 4, II | T323C/Ile108Thr | — | 6.5 | >4 | R | >4 |
| POAr 16 (clpC1-5) 3, I | G341T/Arg114Leu | — | 5.0 | >4 | R | >4 |
| POAr 17 (clpC1-6) 1, II | C577G/Arg193Gly | Rv3626c: G710T/Arg237Leu | 6.0 | >4 | R | >4 |
| POAr 18 (clpC1-7) 2, II | A625G/Lys209Glu | — | 6.0 | >4 | R | >4 |
| POAr 19 (clpC1-8) 3, I | T866C/Leu289Pro | ppe47: Ins14G; yrbE4B: G715A/Gly239Arg | 6.0 | >4 | R | >4 |
Mutants were isolated from four independent batches of bacterial cultures: 1 and 2, selected on Middlebrook 7H10 agar containing 0.5% glycerol; 3 and 4, selected on Middlebrook 7H10 agar without glycerol; I, mutants were selected on agar containing 2 mM POA; II, mutants were selected with 4 mM POA.
Drug susceptibility tests were carried out 3 times independently and mean values are shown.
Polymorphisms were identified by whole-genome sequencing and verified by targeted sequencing as described in the text.
Maximum concentration of drug tested was 4 mM.
BACTEC MGIT 960 test for susceptibility (S) or resistance (R) to 100 μg/ml PZA.
—, not applicable.
Isolated and described in reference 14.
The polymorphism is 10 bp upstream of the clpC1 start codon in the transcribed but untranslated leader sequence (see Fig. 1E).