Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Road, Yuzhong District, Chongqing 400016, PR China.
Infect Genet Evol. 2013 Mar;14:98-101. doi: 10.1016/j.meegid.2012.11.007. Epub 2012 Nov 28.
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.
最广泛的碳青霉烯酶类别的碳青霉烯耐药鲍曼不动杆菌（CRAB）属于β-内酰胺酶（OXA）组。共研究了 57 株 CRAB 分离株和 20 株非 CRAB 分离株（即对碳青霉烯类敏感的鲍曼不动杆菌），以调查 CRAB 分离株的分子流行病学，并确定对亚胺培南耐药的 OXA。在所有 57 株 CRAB 分离株中均检测到 ISAba1-blaOXA-23 样基因，但在非 CRAB 分离株中均未检测到。脉冲场凝胶电泳（PFGE）显示克隆 A 和 B 是主要的基因型，所有 blaOXA-23 样基因阳性株均被分类为克隆 A 或 B 株。ST75 和 ST137 是最突出的序列类型（STs）。最后，克隆 A、C 和 F 的鲍曼不动杆菌分离株均被证明与先前鉴定的欧洲克隆 II 在遗传上相似。总之，产生 blaOXA-23 样基因且上游有 ISAba1 的 ST75 和 ST137 型 CRAB 分离株导致了本研究中发生的医院感染暴发。
