TABLE 4.
Distribution of prothionamide MICs determined by two phenotypic methods
| 7H10 MIC of prothionamide (μg/ml) (no. of strains) | No. of isolates with indicated MGIT960 MIC (μg/ml)a |
||
|---|---|---|---|
| ≤2.5 | >2.5 and ≤5 | >5 | |
| <1 (11) | 11 | 0 | 0 |
| 2 (3) | 2 | 1 | 0 |
| 5 (8) | 3 | 2 | 3 |
| 10 (4) | 1 | 0 | 3 |
| >20 (3) | 0 | 0 | 3 |
a
Twenty-nine isolates were tested. Italics indicate the previously published breakpoint concentration and cutoff for resistance. Boldface indicates proposed breakpoints stemming from the current study; MICs of ≤2 (7H10) or ≤2.5 (MGIT960) μg/ml indicate prothionamide susceptibility, MICs of >10 (7H10) or >5 (MGIT960) μg/ml indicate resistance, and those in between indicate intermediate susceptibility. 7H10, Middlebrook 7H10 agar dilution method; MGIT960, mycobacterium growth indicator tube.