title: Wide distribution of CC92 carbapenem-resistant and OXA-23-producing Acinetobacter baumannii in multiple provinces of China.
abstract: Carbapenem-resistant Acinetobacter baumannii has spread rapidly across China and is currently reported to be a worldwide nosocomial menace. In light of its increasing clinical significance, this study aimed to investigate the molecular epidemiology of carbapenem-resistant and carbapenem-susceptible isolates obtained from multiple provinces of China. Antimicrobial susceptibility was determined by disk diffusion assay according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Multilocus sequence typing (MLST) was used to investigate the molecular epidemiology of the isolates. In addition, a minimum spanning tree algorithm was applied to cluster sequence types (STs) into clonal complexes (CCs) in order to analyse their evolutionary relatedness. Generally, the average rate of resistance to most antibiotics in carbapenem-resistant isolates was extremely high (>85%), except for minocycline (20.45%). Analysis of MLST data confirmed that the genetic background of carbapenem-resistant isolates was relatively simple, with ST92 being the most prevalent clone, occurring in every province, followed by ST138, ST75 and ST381. In contrast, carbapenem-susceptible isolates had a more diverse genetic background. Furthermore, the most widely distributed CC of carbapenem-resistant isolates was bla(OXA-23)-like-producing and predominantly CC92, which incorporate ST136 and its several single-locus variants. Interestingly, isolates belonging to CC92 possessed higher antibiotic resistance rates compared with other STs. Overall, these observations suggest a wide distribution of carbapenem-resistant and bla(OXA-23)-like-producing clone CC92, especially ST92, ST75 and ST138, as the principal reason for the rapidly increasing carbapenem resistance rate in China.
authors.affiliation: Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, No. 3 Qingchun East Road, Hangzhou, Zhejiang 310016, People's Republic of China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Ruan
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhou
authors.forename: Ying
authors.initials: Y
authors.lastname: Fu
authors.forename: Haiping
authors.initials: H
authors.lastname: Wang
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Wang
authors.forename: Yunsong
authors.initials: Y
authors.lastname: Yu
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification* / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015780:Carbapenems / Q000494:pharmacology; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D006761:Hospitals; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D015995:Prevalence; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; C466679:beta-lactamase OXA-23; D001618:beta-Lactamases
keywords: Carbapenem-resistant Acinetobacter baumannii; Clonal complex; MLST; OXA-23