title: Molecular epidemiology of clinical isolates of carbapenem-resistant Acinetobacter spp. from Chinese hospitals.
abstract: Carbapenem resistance in Acinetobacter spp. is an emerging problem in China. We investigated the molecular epidemiology and carbapenemase genes of 221 nonrepetitive imipenem-resistant clinical isolates of Acinetobacter spp. collected from 1999 to 2005 at 11 teaching hospitals in China. Genotyping by pulsed-field gel electrophoresis (PFGE) found 15 PFGE patterns. Of these, one (clone P) was identified at four hospitals in Beijing and another (clone A) at four geographically disparate cities. Most imipenem-resistant isolates exhibited high-level resistance to all beta-lactams and were only susceptible to colistin. bla(OXA-23)-like genes were found in 97.7% of isolates. Sequencing performed on 60 representative isolates confirmed the presence of the bla(OXA-23) carbapenemase gene. Analysis of the genetic context of bla(OXA-23) showed the presence of ISAba1 upstream of bla(OXA-23). All of the 187 A. baumannii isolates identified by amplified RNA gene restriction analysis carried a bla(OXA-51)-like oxacillinase gene, while this gene was absent from isolates of other species. Sequencing indicated the presence of bla(OXA-66) for 18 representative isolates. Seven isolates of one clone (clone T) carried the plasmid-mediated bla(OXA-58) carbapenemase gene, while one isolate of another clone (clone L) carried the bla(OXA-72) carbapenemase gene. Only 1 isolate of clone Q carried the bla(IMP-8) metallo-beta-lactamase gene, located in a class 1 integron. Of 221 isolates, 77.8% carried bla(PER-1)-like genes. Eleven different structures of class 1 integrons were detected, and most integrons carried genes mediating resistance to aminoglycosides, rifampin, and chloramphenicol. These findings indicated clonal spread of imipenem-resistant Acinetobacter spp. and wide dissemination of the OXA-23 carbapenemase in China.
authors.affiliation: Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan, Wangfujing, Beijing 100730, China. wh_bj@tom.com
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Guo
authors.forename: Hongli
authors.initials: H
authors.lastname: Sun
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.forename: Qiwen
authors.initials: Q
authors.lastname: Yang
authors.forename: Minjun
authors.initials: M
authors.lastname: Chen
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Xu
authors.forename: Yuanjue
authors.initials: Y
authors.lastname: Zhu
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D000617:Aminoglycosides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000494:pharmacology; D015139:Blotting, Southern; D015780:Carbapenems / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D002701:Chloramphenicol / Q000494:pharmacology; D003091:Colistin / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006761:Hospitals; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D032023:Integrons / Q000235:genetics; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D012293:Rifampin / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics / Q000494:pharmacology; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D047090:beta-Lactams; D002701:Chloramphenicol; D015378:Imipenem; D001618:beta-Lactamases; C063912:carbapenemase; D012293:Rifampin; D003091:Colistin