Table 2. Antibiotic susceptibility phenotypes of 127 ESBL-EC isolates.
| Antimicrobial agent | MIC range (μg/mL) | MIC50 (μg/mL) | MIC90 (μg/mL) | Susceptibility phenotypea (n) (%) | ||
|---|---|---|---|---|---|---|
| S | I | R | ||||
| (A) Disk diffusion test | ||||||
| Cefpodoxime (10 μg) | N/A | N/A | N/A | 1 (0.8) | 0 (0) | 126 (99.2) |
| Ceftriaxone (30 μg) | N/A | N/A | N/A | 1 (0.8) | 0 (0) | 126 (99.2) |
| Ciprofloxacin (5 μg) | N/A | N/A | N/A | 43 (33.9) | 11 (8.7) | 73 (57.5) |
| Ertapenem (10 μg) | N/A | N/A | N/A | 127 (100) | 0 (0) | 0 (0) |
| (B) Broth microdilution test | ||||||
| Amoxicillin-clavulanic acid | 4–>256 | 32 | 64 | 33 (26) | 30 (23.6) | 64 (50.4) |
| Piperacillin-tazobactam | 16–512 | >512 | >512 | 6 (5) | 23 (19) | 92 (76) |
| Cefoxitin | 4–>256 | 16 | 64 | 56 (44.1) | 35 (27.6) | 36 (28.3) |
| Ceftazidime | 2–>256 | 256 | >256 | 10 (7.9) | 5 (3.9) | 112 (88.2) |
| Cefotaxime | 256–>256 | >256 | >256 | 0 (0) | 0 (0) | 127 (100) |
| Cefepime | 32–>256 | >256 | >256 | 0 (0) | 0 (0) | 127 (100) |
| Imipenem | ≤0.25–4 | 0.5 | 2 | 104 (81.9) | 17 (13.4) | 6 (4.7) |
| Meropenem | ≤0.25–2 | ≤0.25 | 0.5 | 124 (97.6) | 3 (2.4) | 0 (0) |
| Aztreonam | 128–>256 | 256 | >256 | 0 (0) | 0 (0) | 127 (100) |
| Trimethoprim-sulfamethoxazole | >64:1,216 | >64:1,216 | >64:1,216 | 0 (0) | 0 (0) | 127 (100) |
| Flomoxefb | 0.125–>64 | 4 | 32 | 104 (81.9) | 15 (11.8) | 8 (6.3) |
Notes:
N/A, not applicable.
a
S, susceptible; I, intermediate; R, resistant.
b
MIC breakpoints for moxalactam was used as reference (CLSI).