Table 4.
Antimicrobial susceptibility of cephalosporin-resistant Escherichia colib
| Antimicrobial agent | No. (%) of cephalosporin-resistant E. coli isolates (n = 291) according to: |
MICa |
||||||
|---|---|---|---|---|---|---|---|---|
| CLSI 2009 |
CLSI 2010 |
|||||||
| S | I | R | S | I | R | 50 | 90 | |
| Ampicillin | 1 (0.3) | 2 (0.7) | 288 (99) | >16 | >16 | |||
| Ampicillin-sulbactam | 37 (12.7) | 135 (45) | 119 (40.9) | 16/8 | >16/8 | |||
| Piperacillin | 16 (5.5) | 46 (15.8) | 229 (78.7) | >64 | >64 | |||
| Piperacillin-tazobactam | 273 (93.8) | 11 (3.8) | 7 (2.4) | ≤8/4 | 16/4 | |||
| Ticarcillin-clavulanate | 99 (34) | 147 (50.5) | 45 (15.5) | 32/2 | >64/2 | |||
| Cefazolin | 8 (2.7) | 3 (1) | 280 (96.2) | 0 | 0 | 291 (100) | >16 | >16 |
| Ceftriaxone | 50 (17.2) | 56 (19.3) | 185 (63.6) | 15 (5.1) | 9 (3.1) | 267 (91.8) | >32 | >32 |
| Ceftazidime | 158 (54.3) | 67 (23) | 66 (22.7) | 80 (27.5) | 78 (26.8) | 133 (45.7) | 8 | >16 |
| Cefepime | 216 (74.2) | 45 (15.5) | 30 (10.3) | ≤4 | 32 | |||
| Aztreonam | 83 (28.5) | 61 (21) | 147 (50.5) | 45 (15.5) | 38 (13.1) | 208 (71.5) | >16 | >16 |
| Ertapenem | 287 (98.6) | 1 (0.3) | 3 (1) | 278 (95.5) | 2 (0.7) | 11 (3.8) | ≤0.25 | ≤0.25 |
| Imipenem | 291 (100) | 0 | 0 | 288 (99) | 3 (1) | 0 | ≤0.5 | ≤0.5 |
| Meropenem | 289 (99.3) | 2 (0.7) | 0 | 287 (98.6) | 1 (0.3) | 3 (1) | ≤0.5 | ≤0.5 |
| Doripenem | 287 (98.6) | 2 (0.7) | 2 (0.7) | ≤0.5 | ≤0.5 | |||
| Amikacin | 284 (97.6) | 3 (1) | 4 (1.4) | ≤8 | 16 | |||
| Gentamicin | 169 (58.1) | 8 (2.7) | 114 (39.2) | ≤2 | >8 | |||
| Tobramycin | 102 (35.1) | 17 (5.8) | 172 (59.1) | >8 | >8 | |||
| Ciprofloxacin | 51 (17.5) | 0 | 240 (82.5) | >2 | >2 | |||
| Levofloxacin | 49 (16.8) | 1 (0.3) | 241 (82.8) | >8 | >8 | |||
| Cotrimoxazole | 137 (47.1) | 154 (52.9) | >4/76 | >4/76 | ||||
| Tetracycline | 95 (32.6) | 0 | 196 (67.4) | >8 | >8 | |||
| Minocycline | 214 (73.5) | 29 (10) | 48 (16.5) | 2 | >8 | |||
| Nitrofurantoin | 276 (94.8) | 9 (3.1) | 6 (2.1) | ≤32 | ≤32 | |||
| Tigecycline | 290 (99.7) | 1 (0.3) | 0 | ≤1 | ≤1 | |||
a
Values are in μg/ml; 50 and 90, the MICs at which 50 and 90% of the tested isolates are inhibited, respectively. S, susceptible; I, intermediate; R, resistant.
b
Results are based on actual MICs without adjustment for ESBL production. Isolates with unknown resistance mechanisms are not included.