TABLE 1.
Results of antimicrobial susceptibility testing of ESBL-EC isolates
| Antimicrobial agent(s) | MIC (mg/liter)a |
No. (%) of nonsusceptible isolates | ||
|---|---|---|---|---|
| 50% | 90% | Range | ||
| Fosfomycin | 2 | 4 | 0.25–256 | 13 (4.5) |
| Ampicillin | >256 | >256 | 0.06–256 | 273 (93.8) |
| Ampicillin-sulbactam | 64/32 | >64/32 | 0.06/0.03–64/32 | 266 (91.4) |
| Amoxicillin-clavulanic acid | 16/8 | >32/16 | 0.03/0.015–32/16 | 230 (79.0) |
| Ticarcillin-clavulanic acid | 128/2 | >256/2 | 0.25/2–256/2 | 246 (84.5) |
| Ceftazidime | 16 | >64 | 0.06–64 | 166 (57.0) |
| Cefotaxime | >128 | >128 | 0.12–128 | 265 (91.1) |
| Cefepimeb | 128 | >128 | 0.12–128 | 207 (71.1) |
| Aztreonam | 32 | >64 | 0.06–64 | 233 (80.1) |
| Piperacillin-tazobactam | 4/4 | 256/4 | 0.25/4–256/4 | 95 (32.6) |
| Imipenem | 0.12 | 0.25 | 0.06–64 | 1 (0.3) |
| Meropenem | 0.06 | 0.12 | 0.06–64 | 6 (2.1) |
| Doripenem | 0.03 | 0.06 | 0.015–16 | 5 (1.7) |
| Ertapenem | 0.03 | 0.25 | 0.03–32 | 15 (5.2) |
| Ciprofloxacin | 32 | >64 | 0.06–64 | 204 (70.1) |
| Amikacin | 8 | 32 | 0.12–128 | 34 (11.7) |
| Gentamicin | 8 | >64 | 0.06–64 | 151 (51.9) |
| Tobramycin | 8 | 64 | 0.06–64 | 151 (51.9) |
| Tigecycline | 0.25 | 1 | 0.06–64 | 10 (3.4) |
| Colistin | 0.25 | 0.5 | 0.06–64 | |
| Trimethoprim-sulfamethoxazole | >32/608 | >32/608 | 0.03/0.59–32/608 | 157 (54.0) |
a
50% and 90%, MICs at which 50% and 90% of the isolates tested were inhibited.
b
For cefepime, isolates with MICs between 4 and 8 mg/liter (susceptible-dose dependent) were considered susceptible.