TABLE 5.
MICs of several β-lactams and β-lactamase activities for E. coli and H. alvei strains with different genotypes
| Strain | Relevant genotype | MIC (μg/ml)a
|
β-Lactamase activityb (mU/mg of protein)
|
|||||
|---|---|---|---|---|---|---|---|---|
| AMX | PIP | CAZ | CTX | CPO | Basal | Induced | ||
| E. coli | ||||||||
| MC4100 | ampD+ ampE+ ampC | 4 | 0.5 | 0.5 | >0.06 | 0.06 | NDc | ND |
| MC4100(pDEL-2)d | ampD+ ampE+ ampC+ ampR+ | 16 | 8 | 8 | 0.25 | 0.5 | 170 | 29,000 |
| MC4100(pDEL-3)d | ampD+ ampE+ ampC+ ampR | 512 | 256 | 512 | 32 | 16 | 5,860 | 7,040 |
| JRG582 | Δ(ampDE) | 1 | <0.5 | <0.5 | <0.06 | <0.06 | ND | ND |
| JRG582(pDEL-2) | Δ(ampDE) ampC+ ampR+ | 512 | 32 | 64 | 16 | 4 | ND | ND |
| JRG582(pDEL-2, pNH5) | Δ(ampDE) ampC+ ampR+ ampD+ | 128 | 8 | 8 | 0.5 | 0.5 | ND | ND |
| H. alvei | ||||||||
| 1 | 256 | 4 | 2 | 0.25 | 0.5 | 46 | 4,425 | |
| 1 DERe | 512 | 128 | >512 | 128 | 16 | 6,000 | 4,500 | |
| 1 DER(pNH5)e | ampD+ | 256 | 8 | 4 | 0.5 | 0.06 | 23 | 2,500 |
a
Abbreviations; AMX, amoxicillin; PIP, piperacillin; CAZ, ceftazidime; CTX, cefotaxime; CPO, cefpirome.
b
β-Lactamase activities are the geometric mean determinations for three independent cultures. The standard deviations were within 10%.
c
ND, not done.
d
Cefoxitin (5 μg/ml) was used as the inducer.
e
Imipenem (0.5 μg/ml) was used as the inducer.