耐碳青酶烯类鲍氏不动杆菌blaOXA基因型检测及同源性分析

blaOXA Genotype and Genetic Homology of Carbapenem-resistant Acinetobacter baumannii Isolates

目的了解碳青酶烯类耐药鲍氏不动杆菌的耐药性、blaOXA基因型及同源性。方法琼脂稀释法测定鲍氏不动杆菌对14种抗菌药物的最低抑菌浓度(MIC),PCR扩增ISAba1、blaOXA23和bla OXA-66/OXA-51基因,脉冲场凝胶电泳(PFGE)分析基因同源性。结果20株鲍氏不动杆菌对亚胺培南和美罗培南均耐药,其中19株为多药耐药株,1株ISAba1和blaOXA-23阳性,2株blaOXA-66阳性,16株ISAba1、blaOXA-23和blaOXA-66均阳性,1株以上3种基因全部阴性;PFGE分析结果显示,A型(12株)、B型(2株)、C型(2株)、D型(3株)、E型(1株)。结论医院感染的鲍氏不动杆菌对碳青酶烯类耐药可能与产OXA-23酶有关,并存在院内的克隆传播。

OBJECTIVE To investigate the resistance, typing of blaOXA and genetic homology of carbapenemresistant Acinetobacter baumannii. METHODS The minimum inhibitory concentrations （MIC）of fourteen antibiotics were determined by agar dilution method, and ISAbal, blaOXA23 and bla OXA-66/OXA-51 were assayed by PCR. The genetic homology of the isolates was determined by pulsed field gel electrophoresis（PFGE）. RESULTS Twenty strains were all resistant to IMP and MEM and 19 of them were multidrug-resistant strains. The number of positive strains to ISAbal ＋ blaOXA-23, blaOXA-66 and ISAbal＋ blaOXA-23 ＋ blaOXA-66 were 1, 2 and 16 respectively, 1 strain was negative to ISAbal ＋ blaOXA-23 q-blaOXA-66. Twenty strains were classified into Type A（12）, Type B（2）, Type C（2）, Type D（3） and Type E（1） based on PFGE pattern. CONCLUSIONS The resistant mechanism to carbapenem of A. baumanni is probably related to OXA-23 carbapenemase. The prevalence of carbapenem-resistant A. baumannii in our hospital is due to nosocomial infection of cloning strains.