TABLE 2.
MICs for CAZ, CAZ-AVI, and MER for PAO1 isogenic mutants expressing multiple combinations of most relevant β-lactam resistance mechanisms
| Strain | Phenotypea | Reference | MIC (μg/ml) |
||
|---|---|---|---|---|---|
| CAZ | CAZ-AVI | MER | |||
| PAO1 | Wild-type strain | 1 | 1 | 0.5 | |
| PAO ΔdacB | PAO1 PBP4 mutant (↑ampC [ca. 50-fold]) | 15 | 32 | 2 | 0.5 |
| PAO ΔdacC | PAO1 PBP5 mutant | 16 | 1 | 1 | 0.5 |
| PAO ΔdacB ΔdacC | PAO1 PBP4-PBP5 mutant (↑ampC [ca. 500-fold]) | 16 | 64 | 2 | 0.5 |
| PAO ΔdacB ΔpbpG ΔdacC | PAO1 PBP4-PBP5-PBP7 mutant (↑ampC [ca. 1,200-fold]) | 16 | 64 | 2 | 0.5 |
| PAO ΔampD | PAO1 AmpD mutant (↑ampC [ca. 50-fold]) | 17 | 16 | 2 | 1 |
| PAOΔDΔDh2ΔDh3 | PAO1 AmpD-AmpDh2-AmpDh3 mutant (↑ampC [ca. 1,000-fold]) | 17 | 64 | 4 | 1 |
| PAOD1 | OprD− spontaneous PAO1 mutant (W65X) | 12 | 1 | 1 | 2 |
| PAOD1 ΔampD | PAOD1 (OprD−) AmpD mutant (↑ampC [ca. 50-fold]) | 12 | 16 | 2 | 8 |
| PAOΔdB ΔampD | PAO1 PBP4 AmpD mutant (↑ampC [ca. 1,800-fold]) | 15 | 64 | 4 | 1 |
| PAOD1 ΔdacB | PAOD1 (OprD−) PBP4 mutant (↑ampC [ca. 50-fold]) | 12 | 32 | 2 | 2 |
| PAOΔMxR | PAO1 MexR mutant (↑mexB [ca. 10-fold]) | 18 | 4 | 4 | 2 |
| PAODΔMxR | PAOD1 (OprD−) MexR mutant (↑mexB [ca. 10-fold]) | 2 | 4 | 4 | 8 |
| PAOΔDΔMxR | PAO1 AmpD-MexR mutant (↑ampC [ca. 50-fold] + ↑mexB [ca. 10-fold]) | 2 | 32 | 4 | 4 |
| PAOΔNB | PAO1 NfxB mutant (↑mexD [ca. 150-fold]) | 19 | 1 | 1 | 0.25 |
| PAOΔMxZ | PAO1 MexZ mutant (↑mexY [ca. 15-fold]) | 20 | 1 | 1 | 0.5 |
| PAODΔMxZ | PAOD1 (OprD−) MexZ mutant (↑mexY [ca. 15-fold]) | This work | 1 | 1 | 2 |
a
Expression levels and oprD amino acid changes are in reference to PAO1.