TABLE 1.
MICS of β-lactams
| Antibiotic | MIC (μg/ml)a
|
|||
|---|---|---|---|---|
| A. baumannii RYC 52763/97 | E. coli TG1 | E. coli TG1 (pGER1) | E. coli TG1 (pGER2) | |
| Ampicillin | >1,024 | 4 | 128 | >1,024 |
| Ampicillin plus clavulanic acidb | >1,024 | 4 | 64 | 128 |
| Ampicillin plus sulbactamb | >1,024 | 2 | 16 | >1,024 |
| Ampicillin plus tazobactamb | >1,024 | 2 | 32 | 64 |
| Ticarcillin | >1,024 | 4 | 32 | >1,024 |
| Cefazolin | >256 | 8 | >256 | >256 |
| Cefuroxime | >256 | 4 | >256 | >256 |
| Cefoxitin | >256 | 4 | 4 | 4 |
| Cefotaxime | >256 | ≤0.125 | 4 | 8 |
| Cefotaxime plus clavulanic acid | >256 | ≤0.125 | 2 | 4 |
| Cefotaxime plus sulbactam | >256 | ≤0.125 | 0.25 | 2 |
| Cefotaxime plus tazobactam | >256 | ≤0.125 | 0.5 | 1 |
| Ceftazidime | >256 | ≤0.125 | 16 | 32 |
| Ceftazidime plus clavulanic acid | >256 | ≤0.125 | 8 | 16 |
| Ceftazidime plus sulbactam | >256 | ≤0.125 | 1 | 8 |
| Ceftazidime plus tazobactam | >256 | ≤0.125 | 2 | 4 |
| Cefepime | 256 | ≤0.125 | 0.25 | 0.5 |
| Aztreonam | >256 | ≤0.125 | 1 | 4 |
| Imipenem | 128 | 0.25 | 0.25 | 0.25 |
| Meropenem | 256 | 0.03 | 0.03 | 0.03 |
a
Enzymes are as follows: for A. baumannii RYC 52763/97, AmpC plus a β-lactamase with a pI of 9.0 plus TEM-1; for E. coli TG1(pGER1), AmpC; and for E. coli TG1(pGER2), AmpC plus TEM-1. Clone E. coli TG1(pGER2) harbored the ampC gene in the pUC18 multicopy plasmid (containing the blaTEM-1 resistance marker).
b
Concentration of β-lactamase inhibitor was 4 μg/ml.