南京市部分地区医院感染鲍曼不动杆菌的耐药基因和分子流行病学研究

目的了解南京市部分地区医院鲍曼不动杆菌的耐药性及基因分型,探讨不同抗菌药物耐药菌株的分子流行病学特征。方法收集南京市部分地区三级甲等医院2015年5月至2016年5月临床分离的75株鲍曼不动杆菌,通过微生物鉴定系统进行鉴定,采用KB法测定菌株的耐药性,通过脉冲场凝胶电泳判断菌株的基因分型,PCR法测定菌株中的耐药基因,并进行流行病学研究。结果 75株鲍曼不动杆菌在检测的16种抗菌药物中,除替加环素、多黏菌素外,对其他抗菌药物的耐药率均较高,其中对头孢吡肟、头孢他啶、头孢噻肟、头孢泊肟、环丙沙星、四环素的耐性率均达到90%以上;菌株主要分为5型,其中A型和B型所占比例分别为42.67%、37.33%;菌株中基因OXA-23、OXA-24、TEM、SHV、CTX-M、IMP-1、IMP-2、VIM-2的阳性携带率分别为81.33%、9.33%、66.67%、10.67%、42.67%、26.67%、16.00%、21.33%。结论南京部分地区医院鲍曼不动杆菌以A、B型株最为流行,且多为多重耐药菌;菌株中携带的主要耐药基因为OXA-23和TEM,可能是导致该菌对碳青霉烯抗菌药物和β-内酰胺类抗菌药物耐药性高的主要机制。

Study on drug resistance genes and molecular epidemiology of Acinetobacter baumanii in some areas of Nanjing City

Objective To investigate the drug resistance genes of Acinetobacter baumanii in some areas of Nanjing City,and to explore the molecular epidemiology characteristics of different antibiotic resistant strains.Methods A total of 75 strains of Acinetobacter baumanii were isolated from three hospitals of Nanjing city from May 2015 to May 2016 and the strains were identified by microbial identification system.Drug resistances of the strains were determined by KB method.The genotypes of strains were analyzed by pulsed field gel electrophoresis,and PCR was used to amplify the resistance genes.The molecular epidemiology of Acinetobacter baumanii was studied.Results Seventy five strains of Acinetobacter baumanii all had high drug resistance to antibiotics except tigecycline and colistin.The rates of resistance to cefepime,ceftazidime,cefotaxime,ciprofloxacin,cefotaxime,tetracycline were all higher than 90％.The strains were mainly divided into 5 types,and the proportion of A type and B type accounted for 42.67％ and 37.33 ％.The positive rates of genes OXA-23,OXA-24,TEM,SHV,CTX-M,IMP-1,IMP-2 and VIM-2 were 81.33 ％,9.33％,66.67％,10.67％,42.67％,26.67％,16.00％ and 21.33％ respectively.Conclusion A type and B type of the Acinetobacter baumanii are the most popular in hospitals of Nanjing,and the strains are multiple drug resistance.The expression of main resistance genes OXA-23 and TEM strains may be the main mechanism for the higher resistance of the bacteria to antibiotics and β-amide antibiotics.