我院ICU环境多重耐药鲍曼不动杆菌基因多样性检测

Genotype polymorphism of Acinetobacter baumannii isolated from ICU environment

目的了解我院ICU环境中多重耐药鲍曼不动杆菌的主要流行菌株型,为医院感染病原菌的溯源提供数据支持。方法 2010年10月1日-2011年10月1日,每隔2周对外科监护室、神经内科监护室和呼吸科监护室病人周边环境连续采样分离鲍曼不动杆菌,采用V-teck对15种抗生素的药物敏感性进行检测,并采用脉冲场凝胶电泳对环境多重耐药菌分离株进行基因多态性分析;选取病人多重耐药鲍曼不动杆菌分离株4株作为基因型对照。结果监测期间共收集7 878份环境标本,分离鲍曼不动杆菌229株,其中多重耐药鲍曼不动杆菌分离率为1.13%(89/7 878),3个监护室多重耐药鲍曼不动杆菌污染程度差异无统计学意义(P>0.05);89株环境分离多重耐药鲍曼不动杆菌和4株患者鲍曼不动杆菌的基因图谱总体分散,当相似性系数为40%时,可分为A、B、C 3大聚类。89株环境菌株以A2亚类为主(占24.7%),其次为A1亚类和A8亚类(各占15.1%),时间和空间上未见集中趋势。在同一监护室和不同监护室间同源性>90%的病人和环境分离株,在时间和空间上没有流行病学关联。结论 3个监护室在1年的连续监测期间,多重耐药鲍曼不动杆菌基因型呈多样性,未发现耐药菌株的传播,所收集的多重耐药菌株在抗生素的选择压力下源自于环境菌群。

Objective To detect the genotypes of Acinetobater baumannii isolated from ICU environments, and provide basis for hospital infection investigation. Methods The environmental samples from surgical ICU, neurological ICU and respiratory ICU were collected every two weeks continually from October 2010 to October 2011 and Acinetobacter baumannii strains were isolated. The antibiotic susceptibility of 15 kinds antibiotics were detected by V- teck. The genotype polymorphism of multi-drug resistant Acinectobacter baumannii stains was examined by pulsed-field gel electrophoresis（PFGE）. Four strains from patients were selected as the genotype control. Results A total of 7 878 samples were collected. Among 229 Acinetobacter baumannii stains, the isolated rate of multi-drug resistant strains was 1.13%（89/7 878）. The distribution of multi-drug resistant Acinectobacter baumannii in three ICU had no significant difference（P 〉0.05）. There was no central tendency of the genotypes among the 89 multi-drug resistant isolates, of which three types（class A, B and C） were clustered at the similarity of 40%. The subtype A2 was the main type（24.7%）, followed by the subtype A1 and A8, which accounted for 15.1% and 15.1%, respectively. No central tendency was showed in time and space. The patients and the environmental isolates with the similarity of 90% in the same or different ICU showed no epidemiological association. Conclusion During the monitoring period, the genotypes polymorphism of antibiotic resistant Acinectobacter baumannii isolated from three ICU environment show no central tendency, which suggests that the isolates come from environmental flora under antibiotic pressure.