TABLE 3.
Percentages of wild-type and Rv0678 and atpE mutant isolates classified as susceptible or resistant by the four test methods at BDQ phenotypic breakpointsa
| Test method |
BDQ conc |
% of M. tuberculosis isolates showing susceptibility or resistance (no. of susceptible or resistant isolates/total no. of isolates) |
||
|---|---|---|---|---|
| Wild type (susceptible) |
Rv0678
(resistant) |
atpE
(resistant) |
||
| Agar proportion | 0.25 | 99.8 (426/427) | 85.0 (102/120) | 100.0 (30/30) |
| 0.5 | 100.0 (427/427) | 45.0 (54/120) | 100.0 (30/30) | |
| 1 | 100.0 (427/427) | 13.3 (16/120) | 100.0 (30/30) | |
| BMD frozen | 0.12 | 98.2 (425/433) | 97.3 (109/112) | 100.0 (27/27) |
| 0.25 | 99.8 (432/433) | 88.4 (99/112) | 100.0 (27/27) | |
| BMD dry | 0.12 | 99.1 (430/434) | 100.0 (120/120) | 100.0 (30/30) |
| 0.25 | 100.0 (434/434) | 86.7 (104/120) | 100.0 (30/30) | |
| MGIT960 | 1 | 99.8 (443/444) | 100.0 (120/120) | 100.0 (30/30) |
| 2 | 100.0 (444/444) | 66.7 (80/120) | 100.0 (30/30) | |
a
Rows in bold indicate the critical concentration of 0.25 μg/ml using the agar proportion method, BDQ breakpoints of 0.12 μg/ml using the BMD method, and CC of 1 μg/ml using the MGIT960 method. BDQ, bedaquiline; BMD, broth microdilution; CC, critical concentration; MGIT, Mycobacteria Growth Indicator Tube.