Wang Hui, Guo Ping, Sun Hongli, Wang He, Yang Qiwen, Chen Minjun, Xu Yingchun, Zhu Yuanjue
Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan, Wangfujing, Beijing 100730, China.
Antimicrob Agents Chemother. 2007 Nov;51(11):4022-8. doi: 10.1128/AAC.01259-06. Epub 2007 Sep 10.
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.
不动杆菌属对碳青霉烯类抗生素耐药在中国是一个新出现的问题。我们调查了1999年至2005年期间从中国11家教学医院收集的221株非重复的耐亚胺培南不动杆菌属临床分离株的分子流行病学及碳青霉烯酶基因情况。通过脉冲场凝胶电泳（PFGE）进行基因分型发现了15种PFGE图谱。其中，一种（克隆P）在北京的四家医院被鉴定出来，另一种（克隆A）在四个地理位置分散的城市被发现。大多数耐亚胺培南分离株对所有β-内酰胺类抗生素均表现出高水平耐药，仅对黏菌素敏感。97.7%的分离株中发现了bla(OXA-23) 样基因。对60株代表性分离株进行测序证实存在bla(OXA-23) 碳青霉烯酶基因。对bla(OXA-23) 基因背景的分析显示在bla(OXA-23) 上游存在ISAba1。通过扩增RNA基因限制性分析鉴定出的187株鲍曼不动杆菌分离株均携带bla(OXA-51) 样的苯唑西林酶基因，而其他菌种的分离株中不存在该基因。测序表明18株代表性分离株存在bla(OXA-66)。一个克隆（克隆T）的7株分离株携带质粒介导的bla(OXA-58) 碳青霉烯酶基因，而另一个克隆（克隆L）的1株分离株携带bla(OXA-
