TABLE 3.
MICs of β-lactams and activities of BlaA in S. oneidensis and P. aeruginosa
| Strain or mutationa | MIC (μg/ml) forb: |
β-Lactamase activity (mean ± SD) withc: |
||||
|---|---|---|---|---|---|---|
| AMP | CTX | IMP | No inducer | Inducer (50 μg/ml) | Inducer (200 μg/ml) | |
| WT | 4 | 0.02 | 0.5 | 7 ± 1.1 | 25 ± 1.8 | 71 ± 7.6 |
| ΔampD | 4 | 0.02 | 0.5 | 7 ± 1.7 | 29 ± 3.3 | 68 ± 10 |
| ΔampE | 4 | 0.02 | 0.5 | 6 ± 0.6 | 22 ± 3 | 76 ± 10 |
| ΔnagZ | 32 | 0.04 | 2 | 11 ± 1.2 | 54 ± 2.7 | 147 ± 14 |
| ΔampG | 128 | 0.08 | 2 | 13 ± 2.2 | 131 ± 10 | 168 ± 8 |
| ΔblaA | <0.5 | <0.005 | <0.06 | 2 ± 0.3 | 0 | 0 |
| ΔampDΔnagZ | 32 | 0.04 | 2 | 7 ± 0.2 | 75 ± 4.9 | 150 ± 10 |
| ΔnagZ/pHG101 | 32 | 0.04 | 2 | —d | — | — |
| ΔampG/pHG101 | 128 | 0.08 | 2 | — | — | — |
| ΔnagZ/nagZ | 4 | 0.02 | 0.5 | 8 ± 0.7 | 19 ± 1.4 | 59 ± 0.7 |
| ΔampG/ampG | 4 | 0.02 | 0.5 | 6 ± 0.2 | 8 ± 0.9 | 45 ± 3.3 |
| ΔnagZΔblaA | <0.5 | <0.005 | <0.06 | 2 ± 0.4 | 0 | 0 |
| ΔampGΔblaA | <0.5 | <0.005 | <0.06 | 1 ± 0.5 | 0 | 0 |
| ΔnagZ/nagZEC | 4 | 0.02 | 0.5 | — | — | — |
| ΔampG/ampGEC | 4 | 0.04 | 1 | — | — | — |
| PAO1 | 256 | — | — | — | — | — |
| PAO1ΔDDh2Dh3 | 1,024 | — | — | — | — | — |
| PAO1ΔDDh2Dh3/ampDSO | 256 | — | — | — | — | — |
| PAO1ΔG | 32 | — | — | — | — | — |
| PAO1ΔG/ampGSO | 256 | — | — | — | — | — |
a
ΔnagZ/nagZ and ΔampG/ampG represent ΔnagZ and ΔampG strains, respectively, that were complemented with S. oneidensis genes in trans. ΔnagZ/nagZEC and ΔampG/ampGEC represent ΔnagZ and ΔampG strains, respectively, that were complemented with E. coli genes in trans. PAO1ΔDDh2Dh3/ampDSO and PAO1ΔG/ampGSO represent PAO1ΔDDh2Dh3 and PAO1ΔG, respectively, that were complemented with S. oneidensis genes in trans.
b
AMP, ampicillin; CTX, cefotaxime; IMP, imipenem.
c
Nanomoles of nitrocefin hydrolyzed per minute per milligram of protein. Induction was carried out with ampicillin for 2 h.
d
—, not tested.