TABLE 3.
Antibiotic susceptibility profile of B. pseudomallei isolates analyzed in this study and CLSI susceptibility breakpoints for antibioticsa
| Strain or interpretation | Isolate | MIC (μg/ml) |
|||
|---|---|---|---|---|---|
| CAZ | MEM | AMC | SXT | ||
| K96243 | Laboratory | 4 (S) | 1 (S) | 8/4 (S) | 2/38 (S) |
| DR10212A | Primary | 128 (R) | 8 (LS) | 8/4 (S) | 4/76 (R) |
| DR30013A | Primary | 64 (R) | 1 (S) | 2/1 (S) | 2/38 (S) |
| DR80110A | Primary | 16 (I) | 2 (S) | 32/16 (R) | 0.5/9.5 (S) |
| DR90049A | Primary | 2 (S) | 4 (LS) | 8/4 (S) | 0.5/9.5 (S) |
| DR40031A | Primary | 8 (S) | 1 (S) | 16/8 (I) | 1/19 (S) |
| DR80109A | Primary | 1 (S) | 1 (S) | 16/8 (I) | 0.5/9.5 (S) |
| DR50054A | Primary | 2 (S) | 1 (S) | 8/4 (S) | 1/19 (S) |
| DR50054E | Relapse | 64 (R) | 4 (LS) | 32/16 (R) | 0.5/9.5 (S) |
| DR90031A | Primary | 2 (S) | 1 (S) | 4/2 (S) | 0.25/4.75 (S) |
| DR90031E | Relapse | 2 (S) | 4 (LS) | 4/2 (S) | 0.25/4.75 (S) |
| CLSI susceptibility breakpoint interpretation (μg/ml) | S | ≤8 | NA | ≤8/4 | ≤2/38 |
| I | 16 | NA | 16/8 | NA | |
| R | ≥32 | NA | ≥32/16 | ≥4/76 | |
a
MICs for each isolate were determined after 18 h of incubation at 37°C and interpretation as recommended in Clinical Laboratory and Standards Institute (CLSI) M45, 2016 (39). Interpretation for MEM is not available for B. pseudomallei in CLSI. In this study, MEM-LS refers to isolates with an MIC of >2 μg/ml (47). CAZ, ceftazidime; MEM, meropenem; AMC, amoxicillin-clavulanic acid; SXT, trimethoprim-sulfamethoxazole; R, resistant; LS, less susceptible; I, intermediate; S, susceptible; NA, not available. Boldface indicates antibiotic-resistant or intermediate isolates.