Resistance of the carbapenems and homology analysis of Pseudomonas aeruginosa in 28 hospitals in China / 中华检验医学杂志

ABSTRACT

Objective To investigate the resistance of carbapenems,the production of metallobeta-lactamases(MBLs)and homology analysis of Psendomonas aeruginosa in China.Methods A total of 654 Pseudomonas aeruginosa isolates were collected from 28 hospitals in 16 difierent regions during the period from July 2006 to July 2007 as part of the Nosocomial Pathogen Resistance Surveillance(NPRS).MICs of imipenem and meropenem were determined by agar dilutiom PFGE was used to analyze the molecular epidemiology of carbapenem-resistant strains.MBLs were detected by Etest and PCR among carbapenem-non-sensitive strains.The transcription levels of MBLs were determined by real-time reverse transcriptase(RT)-PCR.Results Of the 645 Pseudomonas aeruginosa strains,245(37.5%)were resistant to imipenem and 183(28.0%)were resistant to meropenem.A total of 275 carbapenemnonsusceptible strains and 259 carbapenem-resistant strains were chosen for further study. Among the carbapenem-nonsusecptible strains,8.73%(24/275)of the strains carrried MBLs genes hy PCR,but only 6.55%(18/275)of the strains were detected as MBls-producers bv MBL Etest. The MBLs relative expression levels of the 6 MBL genotype-positive but phenotype-negative strains were significantly lower than those of the other 18 MBL genotype-and phenotype-positive strains(P＜0.05).The 259 carbapenemresistant Pseudomonas aeruginosa strains were divided into 89 clones by PFGE.The 24 MBL genotypepositive strains collected from 6 cities were divided into 9 clones by PFGE.Conclusions The carbapenems resistance of Pseudomonas aeruginosa is severe in China.Clonal dissemination of Pseudomonas aeruginosa has not been detected throughout China.MBLs are not the major carbapenems resistance mechanism in Pseudomonas aeruginosa.