Cross-resistance between triclosan and antibiotics in Pseudomonas aeruginosa is mediated by multidrug efflux pumps: exposure of a susceptible mutant strain to triclosan selects nfxB mutants overexpressing MexCD-OprJ.
Triclosan is an antiseptic frequently added to items as diverse as soaps, lotions, toothpaste, and many commonly used household fabrics and plastics. Although wild-type Pseudomonas aeruginosa expresses the triclosan target enoyl-acyl carrier protein reductase, it is triclosan resistant due to expression of the MexAB-OprM efflux system. Exposure of a susceptible Delta(mexAB-oprM) strain to triclosan selected multidrug-resistant bacteria at high frequencies. These bacteria hyperexpressed the MexCD-OprJ efflux system due to mutations in its regulatory gene, nfxB. The MICs of several drugs for these mutants were increased up to 500-fold, including the MIC of ciprofloxacin, which was increased 94-fold. Whereas the MexEF-OprN efflux system also participated in triclosan efflux, this antimicrobial was not a substrate for MexXY-OprM.
Chuanchuen
R
R
Department of Microbiology, Colorado State University, Fort Collins, Colorado 80523-1677, USA.
Beinlich
K
K
Hoang
T T
TT
Becher
A
A
Karkhoff-Schweizer
R R
RR
Schweizer
H P
HP
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D019450:Genes, MDR / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000378:metabolism*; D014260:Triclosan / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D014260:Triclosan