TABLE 6.
Complementation of the AmpC hyperproduction phenotype of the PAO1 ampD triple mutant (PAΔDDh2Dh3) with plasmids harboring wild-type ampD (pUCPAD), ampDE (pUCPADE), ampDh2 (pUCPADh2), and ampDh3 (pUCPADh3)
| Strain | Ceftazidime MIC (μg/ml) | Avg β-lactamase sp acta ± SD
|
|
|---|---|---|---|
| Basal | Induced | ||
| PAO1 | 1 | 1 | 52 ± 13 |
| PAΔDDh2Dh3 | 48 | 976 ± 165 | 977 ± 114 |
| PAΔDDh2Dh3(pUCP24) | 48 | 932 ± 80 | 1,096 ± 94 |
| PAΔDDh2Dh3(pUCPAD) | 1 | 2.9 ± 0.6 | 37 ± 7 |
| PAΔDDh2Dh3(pUCPADE) | 0.75 | 1.6 ± 0.5 | 32 ± 8 |
| PAΔDDh2Dh3(pUCPADh2) | 1.5 | 2.4 ± 0.6 | 119 ± 23 |
| PAΔDDh2Dh3(pUCPADh3) | 1.5 | 2.1 ± 0.4 | 47 ± 11 |
a
Relative values of β-lactamase activity considering 1 the basal activity of reference strain PAO1 (19 nmol of nitrocefin hydrolyzed/min/mg of protein). For induction experiments, the strains were grown in the presence of 50 μg/ml cefoxitin for 3 h.