TABLE 3.
Drug susceptibilities of the P. aeruginosa strains
| Strain | MIC (μg/ml)a
|
||||||||
|---|---|---|---|---|---|---|---|---|---|
| GENb | AMK | TOB | TIC | ATMc | CAZ | FEP | CIP | NOVc | |
| PAO1 and derivatives | |||||||||
| PAO1 | 1 (0.125) | 2 | 0.5 | 32 | 4 (0.12) | 1 | 2 | 0.25 | 512 (32) |
| MutGR1 | 2 | 8 | 1 | 32 | 4 | 1 | 8 | 0.5 | 512 |
| FE60(pAK1900) | 0.125 | 0.5 | 0.06 | ND | ND | ND | 2 | 0.25 | ND |
| FE60(pAGH97) | 1 | 4 | 0.5 | ND | ND | ND | 8 | 0.5 | ND |
| FE60(pAGH29) | 1 | 4 | 0.5 | ND | ND | ND | 8 | 0.5 | ND |
| FE60(pAGH1018) | 2 | 8 | 1 | ND | ND | ND | 16 | 1 | ND |
| Clinical strains | |||||||||
| 615S | 1 (0.125) | 2 | 0.25 | 1 | 0.12 (—)d | 1 | 2 | 4 | 64 (—) |
| 615R | 8 (0.125) | 16 | 2 | 2 | 0.25 (0.25) | 1 | 4 | 1 | 4 (4) |
| 3020S | 2 (0.125) | 2 | 0.5 | 16 | 2 (0.25) | 1 | 2 | 0.25 | 512 (8) |
| 3020R | 16 (0.25) | 32 | 4 | 2 | 0.25 (0.25) | 1 | 4 | 0.5 | 16 (16) |
| 2715 | 4 (0.125) | 8 | 2 | 2 | 0.5 (0.25) | 1 | 16 | 1 | 16 (8) |
| 2716 | 2 (0.125) | 8 | 1 | 2 | 0.25 (0.25) | 1 | 8 | 2 | 32 (32) |
| 2721 | 16 (0.125) | 32 | 4 | 2 | 0.25 (0.12) | 0.5 | 8 | 1 | 32 (32) |
| 2729 | 8 (0.25) | 16 | 2 | 0.5 | 0.25 (0.25) | 1 | 8 | 1 | 32 (32) |
| 2804 | 64 (0.5) | 128 | 64 | 0.5 | 0.25 (—) | 2 | 32 | 16 | 8 (—) |
| 2858 | 4 (0.125) | 8 | 1 | 2 | 0.25 (—) | 4 | 4 | 0.5 | 64 (—) |
| 2933 | 16 (—) | 32 | 4 | 0.5 | 0.25 (0.12) | 0.5 | 16 | 0.5 | 8 (4) |
| 2998 | 8 (0.125) | 16 | 4 | 0.5 | 0.12 (0.12) | 0.5 | 8 | 1 | 32 (32) |
| 3066 | 64 (0.125) | 128 | 16 | 2 | 0.25 (0.25) | >8 | 32 | 16 | 32 (32) |
Values in boldface type (or underlined) are at least fourfold higher (or fourfold lower) than those for wild-type strain PAO1. Abbreviations: GEN, gentamicin; AMK, amikacin; TOB, tobramycin; TIC, ticarcillin; ATM, aztreonam; CAZ, ceftazidime; FEP, cefepime; CIP, ciprofloxacin; NOV, novobiocin; ND, not determined.
Values in parentheses indicate MICs after the mexXY operon has been repressed in trans by plasmid pAZ17 (in isolates 3020S and 3020R, the inactivation of mexXY was achieved by the chromosomal integration of plasmid pUCΔY). Preliminary experiments showed that the addition of 50 μg/ml ticarcillin to selectively maintain pAZ17 in cultures did not influence MICs.
Values in parentheses indicate MICs after the mexB gene has been inactivated by the FRT cassette from plasmid pEXBR.
—, the inactivation of mexXY or mexB was unsuccessful in these strains.