Extended-spectrum β-Lactamases and Drug Resistance Against Pseudomonas aeruginosa

OBJECTIVE To understand the extended-spectrum β-lactamases(ESBLs) and in vitro antibacterial activity of commonly used antimicrobial agents against Pseudomonas aeruginosa.METHODS All strains were isolated and identified by routine procedure and VITEK-2 automatic bacterial identification instrument.Minimum inhibitory concentration(MIC) detection used agar plate dilution method following the standand of CLSI.PCR was used to amplify the ESBLs genes.Data were analyzed by SPSS.RESULTS Seventy-seven strains of P.aeruginosa were isolated from clinical infectious specimen.The MIC90 of piperacillin/tazobactam was up to 256 μg/ml and cefoperazone/sulbactam and imipenem were 128μg/ml and 32μg/ml,respectively.MIC90 of meropenem and pazufloxacin were both up to 16μg/ml.Among 77 P.aeruginosa strains,21 strains were positive of ESBLs gene with PCR detection,the ratio was 27.3%.But there were not significant differences in MIC of all antibacterial agents between the producing ESBLs strains or not.CONCLUSION The drug resistance of P.aeruginosa isolated from our hospital is very serious.But ESBLs are not the major mechanism of drug resistance.Clinical micrabiological laboratory should strengthen the drug resistant phenotype detection against P.aeruginosa in order to select clinical antimicrobial agents rationally.