title: SmeDEF multidrug efflux pump contributes to intrinsic multidrug resistance in Stenotrophomonas maltophilia.
abstract: Stenotrophomonas maltophilia is an emerging nosocomial pathogen that displays high-level intrinsic resistance to a variety of structurally unrelated antimicrobial agents. Efflux mechanisms are known to contribute to acquired multidrug resistance in this organism, and indeed, one such multidrug efflux system, SmeDEF, was recently identified. Still, the importance of SmeDEF to intrinsic antibiotic resistance in S. maltophilia had not yet been determined. Reverse transcription-PCR confirmed expression of the smeDEF genes in wild-type S. maltophilia, and deletion of smeE or smeF in wild-type strains rendered the mutants hypersusceptible to several antimicrobials, suggesting that SmeDEF contributes to intrinsic antimicrobial resistance in this organism. Expression of smeDEF was also enhanced in an in vitro-selected multidrug-resistant mutant, although deletion of smeF but not of smeE in these mutants compromised antimicrobial resistance. Apparently, hyperexpressed SmeF is capable of functioning with additional multidrug efflux components to promote multidrug resistance in S. maltophilia.
authors.affiliation: Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: X Z
authors.initials: XZ
authors.lastname: Li
authors.forename: K
authors.initials: K
authors.lastname: Poole
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004591:Electrophoresis, Polyacrylamide Gel; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D012329:RNA, Bacterial / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012997:Solvents; D020615:Stenotrophomonas maltophilia / Q000187:drug effects* / Q000235:genetics*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial; C417265:SmeD protein, Stenotrophomonas maltophilia; C417266:SmeE protein, Stenotrophomonas maltophilia; C417267:SmeF protein, Stenotrophomonas maltophilia; D012997:Solvents