【作者】 周华； 潘韵峰； 周志慧； 俞云松； 陈亚岗； 李兰娟；

【Author】 Yun-Feng Pan , Yun-song Yu , Zhihui Zhou, Hua Zhou , Yan-gang Chen , Lan-juan Li. First hospital of Hangzhou; First Affiliated Hospital, College of Medicine, Zhejiang University

【机构】 First Affiliated Hospital,College of Medicine,Zhejiang University； First hospital of Hangzhou；

【摘要】 目的调查国内6个省市25家医院临床分离鲍曼不动杆菌介导高水平氨基糖苷类抗生素耐药的16S rRNA甲基化酶基因armA、rmtA、rmtB的分布情况。方法收集2004年12月-2005年12月国内6省市8家省级医院、浙江省11个地区17家医院临床分离的700株鲍曼不动杆菌;采用琼脂稀释法测定其对5种抗菌药物的MIC 值;PCR筛选三种甲基化酶基因armA、rmtA、rmtB,克隆测序明确基因型;脉冲场凝胶电泳(PFGE)分析菌株的同源性;接合试验、质粒抽提,以及Southern杂交确定armA基因定位。结果对妥布霉素、阿米卡星、庆大霉素、异帕米星、奈替米星耐药率分别为67．7％、70．9％、75．7％、63．5％、71．5％;对5种氨基糖苷类抗生素全部耐药菌株377株,其中334株检出armA基因;未发现rmtA、rmtB基因阳性菌株。armA基因阳性菌株PFOE分型以A、B、C 3型为主。碱裂解法反复抽提未得到质粒,多次接合试验未成功;Soutbern杂交显示armA基因分别位于克隆A、B、C菌株染色体ApaI酶切脉冲场凝胶电泳约220kb、300kb、220kb大小的脉冲场凝胶电泳片断上。结论 16S rRNA甲基化酶基因armA在鲍曼不动杆菌中广泛存在。armA基因定位于鲍曼不动杆菌的染色体上。更多还原

【Abstract】 Objective To investigate the prevalence of 16S rRNA methylases gene in Acinetobacter baumannii isolates from 25 Chinese hospitals. Methods A total of 700 Acinetobacter baumannii isolates were collected from 2004.12 to 2005.12 of 25 hospitals in China. Agar dilution was used to determinate the MIC of these strains to 5 aminoglycosides antibiotics. Three 16S rRNA methylase genes, armA, rmtA and rmtB, were detected by PCR-based assays. PCR products were purified, cloned and sequenced. The homology of armA-positive was analyzed by pulse-field gel electrophoresis (PFGE). Plasmid was extracted, conjugation and southern blot were performed. Results The resistance rates to tobramycin, amikacin, gentamicin, isepamicin, netilmicin were 67.7%, 70.9%, 75.7%, 63.5%, and 71.5%, respectively. Overall, 334 armA-positive isolates were identified. No rmtA, rmtB gene was detected. PFGE analysis indicate that 334 armA-positive isolates, were classified into 3 clone mainly.Clone A、B and C had widely spread in all of these provinces. No plasmid was extracted and conjugation was not successful, despite multiple attempts. Southern blot confirmed that the armA gene was located on the chromosome ApaI digested DNA patterns of these strains. Conclusions Nosocomial spread of armA-producing Acinetobacter baumannii is quite severe in China. ArmA gene was located on the chromosome of these strains.更多还原