title: Nosocomial spread of carbapenem-resistant Acinetobacter baumannii (types ST75 and ST137) carrying blaOXA-23-like gene with an upstream ISAba1 in a Chinese hospital.
abstract: The most widespread type of carbapenemases among carbapenem-resistant Acinetobacter baumannii (CRAB) belongs to the oxacillinase (OXA) group. A total of 57 CRAB isolates and 20 non-CRAB isolates (i.e., A. baumannii susceptible to carbapenems) were studied to investigate the molecular epidemiology of CRAB isolates and to identify the OXAs responsible for resistance to imipenem. The ISAba1-blaOXA-23-like gene was detected in all 57 CRAB isolates but was detected in none of the non-CRAB isolates. Pulsed-field gel electrophoresis (PFGE) revealed that clones A and B were the dominant genotypes, and all blaOXA-23-like gene positive strains were classified as either clone A or B strains. ST75 and ST137 were the most prominent sequence types (STs). Finally, the A. baumannii isolates of clone A, C and F were all demonstrated to be genetically similar to the previously identified European clone II. In conclusion, ST75- and ST137-type CRAB isolates that produced the blaOXA-23-like gene with an upstream ISAba1 contributed to the nosocomial outbreaks studied in this work.
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Road, Yuzhong District, Chongqing 400016, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Dai
authors.forename: Shifeng
authors.initials: S
authors.lastname: Huang
authors.forename: Shan
authors.initials: S
authors.lastname: Sun
authors.forename: Ju
authors.initials: J
authors.lastname: Cao
authors.forename: Liping
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D000483:Alleles; D015780:Carbapenems; D002681:China; D003428:Cross Infection; D015870:Gene Expression; D006801:Humans; D058885:Multilocus Sequence Typing; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D015780:Carbapenems; C466679:beta-lactamase OXA-23; D001618:beta-Lactamases