亚胺培南耐药鲍曼不动杆菌碳青霉烯酶和16SrRNA甲基化酶研究  

Study on carbapenemase and 16S rRNA methylase of imipenem-resistant Acinetobacter baumannii

作　　者：周华[1] 杜小幸[2] 杨青[3] 周建英[1] 俞云松[2] 李兰娟[2] 

机构地区：[1]浙江大学医学院附属第一医院呼吸科,杭州310006 [2]传染病诊治国家重点实验室 [3]浙江大学医学院附属第一医院检验科,杭州310006

出　　处：《中华流行病学杂志》2009年第3期269-272,共4页Chinese Journal of Epidemiology

基　　金：国家自然科学基金资助项目（30770116）

摘　　要：目的研究中国部分地区临床分离亚胺培南耐药鲍曼不动杆菌的碳青霉烯酶基因型及16SrRNA甲基化酶基因。方法收集6省市25家医院2004年12月至2005年12月临床分离的342株亚胺培南耐药鲍曼不动杆菌；采用琼脂稀释法和E—test法测定菌株对14种抗菌药物的最低抑菌浓度（MIC）；脉冲场凝胶电泳（PFGE）分析亚胺培南耐药菌株同源性；PCR及克隆测序分析碳青霉烯酶基因和16SrRNA甲基化酶基因型。结果342株亚胺培南耐药鲍曼不动杆菌对氨苄西林／舒巴坦、头孢哌酮／舒巴坦两个含舒巴坦制剂耐药率分别为68．0％、54．2％，对多粘菌素E耐药率最低为10．8％，对米诺环素耐药率75．9％，对妥布霉素耐药率87．4％，对其他抗菌药物的耐药率均在90％以上；342株亚胺培南耐药鲍曼不动杆菌PFGE分型中303株菌株属于6个广泛流行的克隆株；342株亚胺培南耐药鲍曼不动杆菌中322株携带OXA-23基因，全部携带OXA-66基因，314株菌株OXA-23基因上游检测到插入序列ISAbal，13株OXA-66基因上游检测到ISAbal；287株对阿米卡星、庆大霉素、妥布霉素、异帕米星、奈替米星全部耐药的菌株中有221株携带armA型16SrRNA甲基化酶基因。结论OXA-23组D类β-内酰胺酶基因是最主要的碳青霉烯酶基因型，插入序列ISAbal在介导鲍曼不动杆菌对亚胺培南耐药中起重要作用；16SrRNA甲基化酶基因armA基因在中国亚胺培南耐药鲍曼不动杆菌中分布广泛；克隆播散是亚胺培南耐药鲍曼不动杆菌最主要的传播方式.Objective To investigate the prevalence of 16S rRNA methylases gene in imipenem-resistant Acinetobacter baumannii isolates from China. Methods A total of 342 imipenem- resistant A.baumannii isolates were collected between December 2004 and December 2005, from 25 hospitals of China. Agar dilution was used to determinate the minimal inhibitory concentration （MIC） of these isolates. The homology of these isolates was analyzed by pulse-field gel electrophoresis （PFGE）. Several 16S rRNA methylase genes and carbapenemase genes were detected by PCR-based assays and PCR products were sequenced. Results The rates of resistance to ampicillin-sulbactam, cefoperazone-sulbactam, tobramycin, and minocycline were 68.0%, 54.2%, 87.4%, and 75.9%, respectively. The rate of resistance to polymyxin E was 10.8%, the lowest among the tested agents. The rates of resistance to all other tested antimicrobial agents were more than 90%. The A.baumannii isolates belonged to 29 distinct clones. Among them, 6 clones were dominant, consisting of 303 isolates in total. All isolates contained the blaOXA-51-like gene （blaOXA-66） and 322 isolates contained the blaOXA-23-like gene. PCR with the 1SAbal-OXA-23-like primers generated a PCR product in 314 isolates, and PCR with the ISAbal-OXA-51-like primers generated a PCR product in 13 strains. 221 armA-positive isolates were identified. Conclusion Most of the imipenem-resistant A.baumannii contained blaOXA-23, with ISAbal upstream of the gene. 16S rRNA methylase gene armA was widely distributed in these isolates. The results suggested that the spread of clones played an important role in the outbreak of imipenem-resistant A. baumannii in China.

关 键 词：鲍曼不动杆菌 脉冲场凝胶电泳 碳青霉烯酶 16S rRNA甲基化酶 

分 类 号：R446.5[医药卫生—诊断学]