医院感染鲍曼不动杆菌中Ⅰ类整合子的分布及其同源性研究

Distribution of integon 1 in Acinetobacter baumannii strains from nosocomial infections and their homology

目的:研究临床分离医院感染鲍曼不动杆菌中Ⅰ类整合子的分布及其各菌株间的同源性。方法:以特异性引物分别扩增Ⅰ类整合酶基因和Ⅰ类整合子全基因组,以确定其在鲍曼不动杆菌中的分布,对整合子基因盒进行克隆测序,了解其携带的耐药信息;应用RAPD技术对其进行基因分型,绘制亲缘关系树状图,分析菌株间的同源性。结果:19株医院感染鲍曼不动杆菌中16株携带Ⅰ类整合酶基因,8株携带Ⅰ类整合子基因盒。RAPD技术将其分为4个基因型,其中主要为B型14株,占73.7%,其次为A型3株,C型和D型各1株。C型与B型亲缘关系最近,两者有66%的同源性。结论:医院感染鲍曼不动杆菌中Ⅰ类整合酶的携带率高达84.2%,是鲍曼不动杆菌多药耐药迅速发生的一个重要原因;同源性分析确定我院急诊ICU和住院ICU之间存在多药耐药鲍曼不动杆菌的院内克隆传播。

Objective：To study the distribution of integon 1 in multidrug-resistant Acinetobacter baumannii strains from nosocomial infections and their homology.Methods： Use special primers to amplify class Ⅰ integrase and class Ⅰ integron respectively,than know their distribution during the strains.Randomly amplified polymorphic DNA（RAPD） was used to genotype the strains of Acinetobacter baumannii isolated from nosocomial infection.The homology of these strains were studied by mading dendrogram.Results： The positive of the genes of class Ⅰ integrase and class Ⅰ integron were 16 and 8 respectively in the 19 strains.The strains isolated from nosocomial infctions were classified into 4 genetypes based on RAPD electrophoresis pattern.It is mainly composed by type B,which accounted 73.7%.The second is type A with 3 strains.Type C and B showed the most close similarity levels of 66%.Conclusion： The occurrence rate of class Ⅰ integrase was quite high in the multidrug-resistant Acinetobacter baumannii strains.The positive rate of integron Ⅰ was only its half.There was an epidemic outbreak of multidrug-resistant Acinetobacter baumannii.in our hospital between F06 and D06 by RAPD analyses.