氨基糖苷类修饰酶基因aac(2')-Ib型在耐药鲍曼不动杆菌中流行

Spread of aminoglycoside modifying enzyme gene: aac(2')- Ib in drug-resistant A. baumannii

目的调查一组耐药鲍曼不动杆菌对氨基糖苷类的耐药机制。方法收集2013年1至3月江苏省淮安市第一人民医院住院患者标本中分离到的鲍曼不动杆菌共32株,用分子鉴定法确认为鲍曼不动杆菌,再用聚合酶链反应(PCR)方法分析9种氨基糖苷类修饰酶基因与7种16S r RNA甲基化酶基因。结果本组32株耐药鲍曼不动杆菌共检出5种氨基糖苷类修饰酶基因:aac(2')-Ib 32株(100.0%)、aac(3)-I 15株(46.9%)、aac(6')-Ib 19株(59.4%)、ant(3'')-I 20株(62.5%)、aph(3')-I 19株(59.4%),与1种16S r RNA甲基化酶基因arm A 25株(78.1%)。阳性基因共分为7种检测模式,其中以aac(2')-Ib+aac(3)-I+aac(6')-Ib+ant(3'')-I+aph(3')-I+arm A等6种基因均阳性的模式最高,为12株(37.5%)。结论产5种氨基糖苷类修饰酶基因(aac(2')-Ib、aac(3)-I、aac(6')-Ib、ant(3'')-I、aph(3')-I)与1种16S r RNA甲基化酶基因arm A是本组耐药鲍曼不动杆菌对氨基糖苷类耐药的重要原因。在鲍曼不动杆菌临床分离株检出aac(2')-Ib型氨基糖苷类修饰酶基因为国内首次报道。

Objective To investigate resistant mechanisms of a group of drug-resistant A.baumannii to aminoglycosides.Methods From January 2013 to March 2013,32 strains of drug-resistant Acinetobacter calcoaceticus-baumanii complex were collected from inpatients in Huan＇ an First Hospital,Jiangsu Province,in China.Then,strains were identified as A.baumannii by molecule identification,and 9 kinds of aminoglycoside-modifying enzyme （AME） genes and 7 kinds of 16S rRNA methylase genes were analyzed by PCR.Results In 32strains of A.baumannii,5 kinds of AME genes were positive：32 strains of aac（2＇）-Ⅰb （100.0%）,15 strains of aac（3）-Ⅰ （46.9%）,19 strains of aac（6＇）-Ⅰb （59.4%）,20 strains of ant（3＂）-Ⅰ（62.5%）,19 strains of aph（3＇）-Ⅰ（59.4%）,and a kind of 16S rRNA methylase gene was positive：25 strains ofarmA （78.1%）.And 7 kinds of positive modes were divided into these group ofA.baumannii,and the mode（aac（2＇）-Ⅰb ＋ aac（3）-Ⅰ ＋ aac（6＇）-Ⅰb ＋ ant（3＂）-Ⅰ ＋ aph（3＇）-Ⅰ＋ armA） was highest：37.5%.Conclusion Producing 5 kinds of AME genes and a kind of 16S rRNA methylase gene play a key role in resistance to aminoglycosides in this group ofA.baumannii.And it＇ s the first report that AME：aac（2＇）-Ⅰb was positive in this group ofA.baumannii.