TABLE 1.
Susceptibilities of PAO1 and its β-lactamase- and/or efflux system-deficient mutants to various β-lactams
| Group and antimicrobial agent | MIC (μg/ml)a
|
|||
|---|---|---|---|---|
| PAO1 | KG2239 | KG2504 | KG2507 | |
| Group I | ||||
| Carbenicillin | 25 | 0.39 | 25 | 0.10 |
| Piperacillin | 1.56 | 0.20 | 1.56 | 0.05 |
| Cefoperazone | 3.13 | 0.39 | 1.56 | 0.10 |
| Aztreonam | 3.13 | 0.10 | 1.56 | 0.05 |
| Cefsulodin | 0.78 | 0.20 | 0.78 | 0.20 |
| Group II | ||||
| Amoxicillin | 3,200 | 1,600 | 6.25 | 0.10 |
| Cefmetazole | 1,600 | 1,600 | 100 | 0.20 |
| Flomoxef | 6,400 | 6,400 | 12.5 | 0.20 |
| Panipenem | 3.13 | 3.13 | 0.20 | 0.10 |
| Imipenem | 0.78 | 0.78 | 0.20 | 0.20 |
| Group III | ||||
| Cefpodoxime | 400 | 400 | 100 | 0.20 |
| Cefuroxime | 800 | 400 | 400 | 0.78 |
| Ceftriaxone | 6.25 | 12.5 | 3.13 | 0.20 |
| Moxalactam | 6.25 | 3.13 | 6.25 | 0.39 |
| Meropenem | 0.39 | 0.20 | 0.20 | 0.012 |
| S-4661 | 0.20 | 0.39 | 0.10 | 0.025 |
a
PAO1 produced AmpC and MexAB-OprM, KG2239 produced AmpC but was MexAB-OprM deficient, KG2504 was AmpC deficient but produced MexAB-OprM, and KG2507 was AmpC and MexAB-OprM deficient.