TABLE 3.
MICs of β-lactam antibiotics and specific activities of E. cloacae AmpC in E. coli ampD mutants containing the ampDE genes of P. aeruginosa mutant
| Strain and plasmids | Relevant genotype | MIC (μg/ml)
|
β-Lactamase activitya
|
||
|---|---|---|---|---|---|
| Ampicillin | Cefotaxime | Noninduced | Inducedb | ||
| STC172/pEC1C/pBGS19+c | ampC+ ampR+/ampD11E+ | 1,024 | 32 | 3,260 ± 190 | 23,490 ± 1,240 |
| STC172/pEC1C/pHUL4DE-2c | ampC+ ampR+/ampDEPAO1 | 128 | 1 | 113 ± 5 | 2,930 ± 199 |
| STC172/pEC1C/pHUL4DE-M1 | ampC+ ampR+/ampDE4254 | 128 | <2 | 32 ± 1 | 2,000 ± 60 |
| STC172/pEC1C/pHUL4DE-M2 | ampC+ ampR+/ampDEPs50SAI+ | 128 | <2 | 30 ± 1 | 200 ± 10 |
| STC172/pEC1C/pHUL4DE-M3 | ampC+ ampR+/ampDEPs50SAI−con | 512 | <2 | 20 ± 1 | 900 ± 4 |
| STC172/pEC1C/pHUL4DE-M4 | ampC+ ampR+/ampDEM1405 | 256 | <2 | 400 ± 20 | 800 ± 40 |
| STC172/pEC1C/pHUL4DE-M5 | ampC+ ampR+/ampDEM2297P | 256 | <2 | 20 ± 0.7 | 832 ± 50 |
| STC172/pEC1C/pHUL4DE-M6 | ampC+ ampR+/ampDEM2297P−con | 256 | <2 | 134 ± 6 | 2,100 ± 90 |
| JRG582/pEC1C/pBGS19+c | ampC+ ampR+/Δ(ampDE)2 | 1,024 | 64 | 103,280 ± 6,230 | 109,400 ± 7,110 |
| JRG582/pEC1C/pHUL4DE-2c | ampC+ ampR+/ampDEPAO1 | 128 | 8 | 414 ± 39 | 7,050 ± 400 |
| JRG582/pEC1C/pHUL4DE-M5 | ampC+ ampR+/ampDEM2297P | 256 | <2 | 60 ± 4 | 1,130 ± 70 |
| JRG582/pEC1C/pHUL4DE-M6 | ampC+ ampR+/ampDEM2297P−con | 256 | <2 | 105 ± 8 | 1,770 ± 80 |
a
Nanomoles of nitrocefin hydrolyzed per minute per milligram of protein.
b
Induction was carried out with 4 μg of cefoxitin/ml for 1 h.
c
Data from Langaee et al. (19).