TABLE 2.
Antimicrobial susceptibililies of efflux pump mutant strains
| Strain | Mex efflux (outer membrane protein) expressed | MIC (μg/ml)a
|
|||
|---|---|---|---|---|---|
| TRI | TC | CIP | ERY | ||
| PAO1 | MexAB (OprM) MexXiYib | >128c | 16 | 0.064 | 512 |
| PAO238 | MexXiYi | 20 | 0.75 | 0.006 | 32 |
| PAO238-1 | MexJK MexXiYi | 128 | 1 | 0.004 | 16 |
| PAO298 | MexXiYi | 20 | NDd | 0.004 | 32 |
| PAO314 | MexXiYi | 20 | 0.75 | 0.006 | 32 |
| PAO238-1(pVLT35) | MexJK MexXiYi | >128 | 0.75 | 0.004 | 16 |
| PAO238-1(pPS1180) | MexJK MexXiYi (OprM) | >128 | 16 | 0.047 | 256 |
| PAO314(pVLT35) | MexXiYi | 32 | 0.38 | 0.006 | 16 |
| PAO314(pPS1180) | MexXiYi (OprM) | 32 | 10 | 0.016 | 128 |
| PAO327(pVLT35) | MexJK | 128 | 0.19 | 0.004 | 8 |
| PAO327(pPS1180) | MexJK (OprM) | 128 | 1.0 | 0.008 | 64 |
| PAO325/pVLT35 | None | 16 | 0.19 | 0.004 | 16 |
| PAO325(pPS1180) | (OprM) | 16 | 0.25 | 0.006 | 16 |
| PAO238-1(pUCP20T) | MexJK MexXiYi | >128 | 0.75 | 0.004 | 16 |
| PAO238-1(pPS1153) | MexJK MexXiYi | 20 | 0.75 | 0.006 | 16 |
| PAO318 | MexJK MexXiYi | >128 | 0.75 | 0.006 | 16 |
| PAO318(pUCP20T) | MexJK MexXiYi | >128 | 0.5 | 0.004 | 16 |
| PAO318(pPS1153) | MexJK MexXiYi | 20 | 0.5 | 0.004 | 16 |
a
Abbreviations: CIP, ciprofloxacin; ERY, erythromycin; TC, tetracycline; TRI, triclosan. All mutants were additionally tested for their susceptibilities to acriflavine, dichlorophene, carbenicillin, fusidic acid, gentamicin, hexachlorophene, and trimethoprim, most of which are substrates of other efflux systems but not MexJK.
b
MexXiYi, induced MexXY.
c
At concentrations of >128 μg/ml, triclosan is insoluble in aqueous solutions.
d
ND, not done.