Table 1.
MICs of MmpL3 inhibitors against M. tuberculosis [Mtb], M. abscessus complex species (M. abscessus subsp. abscessus ATCC 19977 [Mabs]; M. abscessus subsp. massiliense CIP 108297 [Mmas]; M. abscessus subsp. bolletii ATCC 14472 [Mbol]), M. avium 104 [Mav], and M. smegmatis recombinant strains expressing different mmpL3 orthologs.
| Inhibitor | Structure | Mtb | Msmg | Mav | Mabs | Mmas | Mbol | MsmgΔmmpL3 | ||
|---|---|---|---|---|---|---|---|---|---|---|
| mmpL3smg | mmpL3abs | mmpL3tb | ||||||||
| PIPD1 |  |
0.15a | <1 | 125b | 0.125 | 0.125 | nd | nd | nd | nd |
| AU1235 |  |
0.1–0.2 | 1.6–2.5 | >32 | 0.5 | 1 | 0.5 | 2 | 2 | 0.3 |
| BM212 |  |
6 | 8–12 | 2 | 1–2 | 1–2 | nd | 8–12 | 8 | 4–6.2 |
| SQ109 |  |
0.6-0.8 | 6.2–12.4 | 4 | >32 | >32 | nd | 8–12 | 16 | 0.4–0.8 |
| THPP1 |  |
0.4-0.8 | >25 | >16 | >16 | >16 | nd | >32 | >32 | 0.8–2 |
| NITD304 |  |
0.004 | 1 | 8 | 0.016 | 0.016 | nd | 1 | 0.12 | 0.06 |
| NITD349 |  |
0.008 | 1 | 8 | 0.016 | 0.031 | nd | 0.25 | 0.25 | 0.06–0.12 |
| IC5 |  |
0.2 | 1.6–3.2 | >32 | 0.25 | 0.5 | 0.25 | 1.6–3.2 | 3.2 | 0.2 |
| IC6 |  |
1.25 | >20 | >32 | >32 | >32 | >32 | >32 | >32 | 1.25 |
| IC9 |  |
0.39 | >25 | >32 | >32 | >32 | 32 | 32 | >32 | 0.25–0.39 |
| IC10 |  |
0.39 | 25 | >32 | >32 | >32 | 32 | 25 | >32 | 0.2 |
| IC15 |  |
5 | 12.5 | >32 | >32 | 16 | 16 | 8–12.5 | >32 | 3–4 |
| IC16 |  |
0.05 | 0.8 | 8 | 0.12 | 0.06 | 0.12 | 3–4 | 4 | 0.06 |
| IC20 |  |
0.02 | >20 | >32 | >32 | >32 | >32 | >32 | >32 | 0.16 |
| IC21 |  |
0.04 | >20 | >32 | >32 | > 32 | >32 | >32 | >32 | 0.45 |
| IC24 |  |
0.04 | >20 | >32 | >32 | >32 | >32 | >32 | >32 | 0.16 |
| IC25 |  |
0.02 | 0.3–0.6 | 0.25–0.5 | 0.06 | 0.03 | 0.04 | 0.8–1 | 0.5 | 0.08 |
| IC26 |  |
0.08 | 0.6 | 2 | 0.03 | 0.06 | 0.03 | 0.6–1 | 1 | 0.16–0.25 |
| IC29 |  |
0.31 | >20 | >32 | 0.06 | 0.06 | 0.03 | >32 | 1 | 0.62 |
| IC30 |  |
0.16 | nd | >32 | 0.125 | 0.125 | 0.06 | 2 | 1 | 0.25–0.31 |
| APRA | – | 1 | nd | 2 | 2 | 4 | nd | 2 | 4 | 2 |
| BDQ | – | 0.5–1 | nd | 0.01 | 0.0625 | nd | nd | <0.03 | <0.03 | <0.03 |
| CFZ | – | 0.5–1 | nd | <0.125 | 0.125 | nd | nd | 1 | 1 | 0.5 |
| CLA | – | <0.125 | 0.125 | 0.5-1 | 0.25 | nd | 0.5 | 1 | 0.5 | |
MICs (in μg/mL) were determined were determined in 96-well microtiter plates at 37°C in 7H9-ADC-0.05% Tween 80 medium (M. smegmatis), 7H9-OADC-0.05% tyloxapol supplemented with 0.2% casaminoacids, 48 μg/ml pantothenate, and 50 μg/ml L-leucine (M. tuberculosis mc26206), cation-adjusted Mueller-Hinton broth (M. abscessus complex) or in cation-adjusted Mueller-Hinton broth supplemented with 5% OADC (M. avium) using the resazurin blue test (Martin et al., 2003) and by visually scanning for growth. The orthologs of mmpL3 from M. abscessus (mmpL3abs), M. tuberculosis (mmpL3tb), and M. smegmatis (mmpL3smg) are expressed from the replicative plasmid pMVGH1 under control of the hsp60 promoter in the background of a M. smegmatis null mutant (MsmgΔmmpL3) of which the entire mmpL3 ORF was deleted and replaced with a kanamycin-resistance cassette. Control drugs: APRA, apramycin; BDQ, bedaquiline; CFZ, clofazimine; CLA, clarithromycin. nd, not determined.
MIC value against M. tuberculosis H37Rv ATCC 27294 (Low et al., 2017);
The precise M. avium strain used by Dupont et al. (2016) in the MIC determination of PIPD1 was not indicated and may be different from M. avium 104.