TABLE 1.
Susceptibility of E. coli strains to representative β-lactams
| β-Lactam | MIC (μg/ml) for E. coli strain:
|
||||||
|---|---|---|---|---|---|---|---|
| 1285 (CMY-33) | YD006 (CMY-33) | 34943 (CMY-44) | DH10B (pCMY-33)a | DH10B (pCMY-44)a | DH10B (pCMY-2)a | DH10B (pBCSK−) | |
| Ampicillin | >256 | 128 | >256 | >256 | >256 | >256 | 3 |
| Piperacillin | >256 | 12 | >256 | 64 | 32 | 128 | 2 |
| Piperacillin-tazobactam | 128 | 2 | 96 | 6 | 16 | 4 | 1 |
| Cefuroxime | >256 | 96 | >256 | 128 | 64 | >256 | 6 |
| Ceftazidime | >256 | >256 | >256 | >256 | >256 | >256 | 0.5 |
| Cefotaxime | >256 | 8 | 32 | 12 | 8 | 16 | 0.064 |
| Cefoxitin | >256 | 24 | >256 | 24 | 32 | >256 | 6 |
| Cefepime | 96 | 6 | 32 | 6 | 3 | 0.25 | 0.032 |
| Aztreonam | 64 | 6 | 24 | 16 | 4 | 8 | 0.064 |
| Ertapenem | 1 | 0.064 | 4 | 0.032 | 0.064 | 0.094 | 0.012 |
a
Isogenic strains of E. coli DH10B with pBCSK− vector containing blaCMY-33, blaCMY-44, and blaCMY-2, respectively.