宁波地区鲍曼不动杆菌16S rRNA甲基化酶基因研究

Study on 16S rRNA methylase genes among acinetobacter baumannii in Ningbo

目的:调查宁波地区3家综合性医院临床分离鲍曼不动杆菌中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:收集宁波市李惠利医院、宁波市第一人民医院、宁波市第二人民医院氨基糖苷类抗生素高水平耐药鲍曼不动杆菌20株。琼脂稀释法测定5种氨基糖苷类抗菌药物的MIC值;PCR检测ar-mA、rmtA、rmtB 3种16S rRNA甲基化酶基因,克隆测序明确基因型;脉冲场凝胶电泳(PFGE)分析菌株同源性。结果:对5种氨基糖苷类抗生素全部耐药的20株菌株中,17株检出armA基因;未发现rmtA、rmtB基因阳性菌株。armA基因阳性菌株PFGE分型以A型为主。结论:宁波地区鲍曼不动杆菌检测出16S rRNA甲基化酶基因armA,菌株以克隆播散形式流行。

Objective：To investigate the prevalence of 16S rRNA methylases genes in Acinetobacter baumannii isolates isolated from 3 comprehensive hospitals in Ningbo.Methods：A total of 20 strains of five aminoglycosides high-level resistant Acinetobacter baumannii were collected from 3 hospitals of Ningbo.The minimum inhibitory concentrations（MIC） of these strains were examined by agar dilution method.Three 16S rRNA methylase genes,armA,rmtA and rmtB,were detected by PCR-based assays.PCR products were purified and sequenced.The homology of armA-positive strains were analyzed by pulse-field gel electrophoresis（PFGE）.Results：Seventeen armA-positive isolates were identified from 20 Acinetobacter baumannii isolates which are high-level resistance to five aminoglycosides.No rmtA,rmtB gene was detected.PFGE analysis indicated that 17 armA-positive isolates were classified into clone A and B,Clone A had spread widely.Conclusion：ArmA-producing Acinetobacter baumannii isolates are detected in Ningbo.The clone transmission has spreaded severely.