title: Molecular epidemiology and mechanisms of carbapenem resistance in Pseudomonas aeruginosa isolates from Chinese hospitals.
abstract: We investigated the molecular epidemiology and carbapenem resistance mechanisms of 258 non-duplicate carbapenem-resistant clinical isolates of Pseudomonas aeruginosa collected from 2006 to 2007 at 28 hospitals in China. Up to 88% of the carbapenem-resistant isolates were multidrug-resistant. Pulsed-field gel electrophoresis (PFGE) revealed that levels of intrahospital and interhospital dissemination of clones were low. To assess the mechanisms leading to resistance, all 258 carbapenem-resistant isolates were analysed for expression of the chromosomal beta-lactamase (AmpC), the porin important for entry of carbapenems (OprD) and an efflux system (MexAB-OprM) known to extrude some beta-lactams. Carbapenem resistance was driven mainly by mutational inactivation of OprD, accompanied or not by hyperexpression of AmpC or MexAB-OprM. Metallo-beta-lactamase genes were detected in 22 carbapenem-resistant isolates in China, belonging to eight pulsotypes. The bla(OXA-50) gene was detected among all of the carbapenem-resistant isolates, whereas the bla(GES-5) gene was detected in only one carbapenem-resistant isolate.
authors.affiliation: Respiratory Department, The 1st Affiliated Hospital, Medical School, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Jian-ying
authors.initials: JY
authors.lastname: Zhou
authors.forename: Ting-ting
authors.initials: TT
authors.lastname: Qu
authors.forename: Ping
authors.initials: P
authors.lastname: Shen
authors.forename: Ze-qing
authors.initials: ZQ
authors.lastname: Wei
authors.forename: Yun-song
authors.initials: YS
authors.lastname: Yu
authors.forename: Lan-juan
authors.initials: LJ
authors.lastname: Li
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D015780:Carbapenems / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006761:Hospitals; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D018272:Porins / Q000235:genetics; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; D018272:Porins; C077157:OprD protein, Pseudomonas aeruginosa; D001618:beta-Lactamases