多耐药鲍氏不动杆菌菌株亲缘性分析

Phylogenetic Analysis of Multi-drug Resistant Strains of Acinetobacter baumannii

目的了解医院感染多耐药鲍氏不动杆菌(MDR-ABA)的耐药基因及亲缘性。方法采用PCR对20株MDR-ABA进行β-内酰胺酶基因、氨基糖苷类耐药基因、转座子遗传标记、整合子遗传标记共36种耐药基因的检测,并以耐药基因作为分子标志作聚类分析;同时用脉冲场凝胶电泳(PFGE)进行分子同源性检测以作参照。结果 20株MDR-ABA中,TEM、ADC、OXA-23群阳性率分别为100%、75%、50%,而其他β-内酰胺酶相关基因均为阴性;aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6′)-Ⅰb、ant(3″)-Ⅰ阳性率分别为10%、15%、30%、25%;转座子遗传标记tnpU检出率为55%、整合子遗传标记qacE△1-sul1阳性15株(75%),并对检测结果作样本聚类分析,聚类分析提示20株MDR-ABA可分为A、B两群,均存在克隆传播现象;而PFGE法通过图形条带分析所得结果与聚类分析结果具有一定差异。结论 MDR-ABA耐药基因检出率较高,并可导致医院内克隆传播感染,聚类分析比PFGE更能反映菌株遗传信息,是分析同源性更科学方法。

OBJECTIVE To investigate the resistance gene and phylogenetic analysis in multi-drug resistant strains of Acinetobacter baumannii.METHODS The 36 kinds of drug resistance genes from 20 strains of MDR-ABA,including β-lactamase gene,aminoglycoside drug resistance gene,transposon genetic mark,and integron genetic markers were detected by applying polymerase chain reaction（PCR）.The cluster analysis was conducted using drug resistance genes as molecule markers,and the molecular homology was analyzed by by pulsed field gel electrophoresis（PFGE） as a reference.RESULTS The positive rates of TEM,ADC,OXA-23 group gene were 100%,75% and 50%,respectively,and the other β-lactamase genes were all negative.The positive rates of aac（3）-Ⅰ,aac（3）-Ⅱ,aac（6′）-Ⅰb,and ant（3″）-Ⅰ were 10%,15%,30%,and 25%,respectively.The detected rate of transposon genetic mark tnpU was 55%;and 15（75%） strains with integron genetic markers qacE△1-sul1.The 20 samples could be separated to A and B two groups,and clone transmission was shown through the sample clustering analysis.There were differences of the results between clustering analysis and PFGE.CONCLUSIONS The MDR-ABA can induce clone transmission infection in hospital and there is very high detection rate of drug resistance gene in MDR-ABA.The clustering analysis can obtain more genetic information,and is more scientific in analyzing the molecular homology than PFGE.