TABLE 1.
β-Lactam MICs for E. coli DH5α producing CTX-M-9, the S130G mutant, and the D240K mutant
| Substrate(s) | MIC (μg/ml) for E. coli DH5α producing:
|
|||
|---|---|---|---|---|
| S130G mutant | D240K mutant | CTX-M-9 | No enzyme | |
| Amoxicillin | >2,048 | >2,048 | >2,048 | 2 |
| Amoxicillin + CLAa | 256 | 8 | 8 | 2 |
| Ticarcillin | >2,048 | >2,048 | >2,048 | 2 |
| Ticarcillin + CLAa | 512 | 32 | 16 | 2 |
| Piperacillin | ≤64 | ≤64 | 256 | 2 |
| Piperacillin + TZBb | 4 | 2 | 2 | 2 |
| Cephalothin | 64 | 256 | 512 | 4 |
| Cefotaxime | 0.25 | 8 | 8 | 0.06 |
| Ceftazidime | 0.12 | 1 | 1 | 0.12 |
| Aztreonam | 0.12 | 2 | 4 | 0.06 |
a
Clavulanate at a fixed concentration of 2 μg/ml.
b
Tazobactam at a fixed concentration of 4 μg/ml.