title: Multidrug efflux in intrinsic resistance to trimethoprim and sulfamethoxazole in Pseudomonas aeruginosa.
abstract: Pseudomonas aeruginosa possesses at least two multiple drug efflux systems which are defined by the outer membrane proteins OprM and OprJ. We have found that mutants overexpressing OprM were two- and eightfold more resistant than their wild-type parent to sulfamethoxazole (SMX) and trimethoprim (TMP), respectively. For OprJ-overproducing strains, MICs of TMP increased fourfold but those of SMX were unchanged. Strains overexpressing OprM, but not those overexpressing OprJ, became hypersusceptible to TMP and SMX when oprM was inactivated. The wild-type antibiotic profile could be restored in an oprM mutant by transcomplementation with the cloned oprM gene. These results demonstrate that the mexABoprM multidrug efflux system is mainly responsible for the intrinsic resistance of P. aeruginosa to TMP and SMX.
authors.affiliation: Department of Genetics and Microbiology, Centre Médical Universitaire, Geneva, Switzerland. kohler@cmu.unige.ch
authors.forename: T
authors.initials: T
authors.lastname: Köhler
authors.forename: M
authors.initials: M
authors.lastname: Kok
authors.forename: M
authors.initials: M
authors.lastname: Michea-Hamzehpour
authors.forename: P
authors.initials: P
authors.lastname: Plesiat
authors.forename: N
authors.initials: N
authors.lastname: Gotoh
authors.forename: T
authors.initials: T
authors.lastname: Nishino
authors.forename: L K
authors.initials: LK
authors.lastname: Curty
authors.forename: J C
authors.initials: JC
authors.lastname: Pechere
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D003001:Cloning, Molecular; D018432:Drug Resistance, Multiple; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D013762:Tetrahydrofolate Dehydrogenase