多重耐药鲍曼不动杆菌耐药性与整合子关系研究

Relationship between resistance and integron of multidrug-resistant Acinetobacter baumannii

目的了解多重耐药鲍曼不动杆菌整合子的表达及耐药基因的携带情况。方法收集2012年8—10月某院临床分离的51株多重耐药鲍曼不动杆菌,对其进行药敏试验;采用聚合酶链反应(PCR)检测Ⅰ、Ⅱ、Ⅲ类整合酶基因及整合子可变区基因盒,应用限制性片段长度多态性(RFLP)分析和测序结果进行同源性分析。结果多重耐药鲍曼不动杆菌整合酶基因阳性率为78.43%(40/51),均为Ⅰ类整合子,未检出Ⅱ、Ⅲ类整合子。Ⅰ类整合子阳性菌中,39株(97.50%)扩增出可变区,检出5种耐药基因盒组合形式,分别为aacA4(14株)、aacA4+catB8(22株)、arr-3+aacA4(1株)、dfrA15(1株)和arr-3(1株)。结论该院临床分离的多重耐药鲍曼不动杆菌的耐药性可能与Ⅰ类整合子表达有关。Ⅰ类整合子主要携带aacA4、aacA4+catB8、arr-3+aacA4、dfrA15和arr-3基因盒。

Objective To investigate the expression and resistant gene of integron in multidrug-resistant Acinetobacter baumannii （MDR-Ab）.Methods 51 strains of MDR-Ab isolated from a hospital in August-October 2012 were collected, antimicrobial susceptibility testing was performed.Class Ⅰ（Int Ⅰ）,Ⅱ （Int Ⅱ）and Ⅲ （Int Ⅲ）of integrase genes and inte-gron variable region gene cassettes were detected by polymerase chain reaction （PCR）,and the homology of integron varia-ble region was analyzed by detection results of restriction fragment length polymorphism （RFLP）and DNA sequencing. Results Positive rate of integrase gene in MDR-Ab was 78.43%（40/51）.All genes belonged to Int Ⅰ,while IntⅡand IntⅢ were not found.Variable region cassettes were detected in 97.50% （n=39）of Int I,there were 5 types of integron gene cassettes：aacA4 in 14 strains,aacA4＋catB8 in 22 strains,arr-3 ＋aacA4 in 1 strain,dfrA15 in 1 strain and arr-3 in 1 strain.Conclusion MDR-Ab isolated from this hospital may be related with Int I expression.Int I carried gene cassettes as follows：aacA4,aacA4＋catB8,arr-3＋aacA4,dfrA15 and arr-3.