Table 3.
MICs of β-lactam antibiotics for the clinical K. pneumoniae strains CH719 and CH608 and the derivative strains CH864 and CH865a
| β-Lactamb | MIC for Klebsiella pneumoniae strain |
|||
|---|---|---|---|---|
| CH719 (ampR+ampD+) | CH608 (ampR deficient ampD+) | CH864 (ampR+ampD+) | CH865 (ampR+ampD deficient) | |
| Amoxicillin | >512 | 32 | >512 | >512 |
| Amoxicillin-CLA | >512 | 2 | >512 | >512 |
| Cephalothin | >512 | 8 | >512 | >512 |
| Cefotaxime | 4 | <0.06 | 8 | 64 |
| Cefotaxime-CLA | 16 | <0.06 | 16 | 64 |
| Ceftazidime | 32 | 0.25 | 64 | >512 |
| Ceftazidime-CLA | 64 | 0.25 | 256 | >512 |
| Aztreonam | 4 | 0.25 | 4 | 32 |
a
Specific activities against cephalothin for strains CH719, CH608, CH864, and CH865, without cefoxitin induction, were 1.1, <0.1, 2.2, and 80.0 μmol/min/mg, respectively. Those with induction were 74.7, <0.1, 57.1, and 123.9 μmol/min/mg, respectively. Note that the values for CH608 are identical to those for CH816 (ampD deficient and ampR deficient).
b
CLA, clavulanic acid at 2 μg/ml.