Contribution of integrons, and SmeABC and SmeDEF efflux pumps to multidrug resistance in clinical isolates of Stenotrophomonas maltophilia.
OBJECTIVE
The contribution of integrons and efflux pumps to multidrug resistance in Stenotrophomonas maltophilia was evaluated.


METHODS
Ninety-three S. maltophilia clinical isolates were studied. PCR and direct sequencing were used to detect the presence of integrons. Real-time PCR was performed to assess and quantify the expression of the Sme efflux pumps of S. maltophilia.


RESULTS
Class 1 integrons were detected in 22% of clinical isolates and carried cassettes conferring resistance mainly to aminoglycosides and trimethoprim. The small multidrug resistance gene, smr, was found on class 1 integrons in six isolates. Thirty-one percent of the isolates overexpressed the smeDEF gene, as compared with a control strain, and 59% overexpressed the smeABC gene. Extrusion of ciprofloxacin and meropenem was specific to the SmeABC and SmeDEF pumps, respectively.


CONCLUSIONS
SmeABC and SmeDEF efflux pumps play important roles in resistance of S. maltophilia to ciprofloxacin and meropenem.
Chang
Lin-Li
LL
Department of Microbiology, Kaohsiung Medical University, Kaohsiung, Taiwan. m725006@kmu.edu.tw
Chen
Hui-Feng
HF
Chang
Chung-Yu
CY
Lee
Tsong-Ming
TM
Wu
Wen-Jeng
WJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D006801:Humans; D007438:Introns / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D012329:RNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020615:Stenotrophomonas maltophilia / Q000187:drug effects / Q000235:genetics*
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial