临床分离肠杆菌科细菌Ⅰ型整合子和ISCR1的检测

Detection of class Ⅰ integrons and ISCR1 in clinical enterobacteriaceae

目的了解临床分离的肠杆菌科细菌一类整合子和插入序列共同区(ISCR1)的分布,并分析其相关结构。方法收集2016年9月-2019年11月临床分离的肠杆菌科细菌289株。使用VITEK 2 Compact全自动微生物分析仪进行细菌鉴定。采用PCR法扩增Ⅰ类整合酶基因和ISCR1基因,并分别扩增整合子和ISCR1可变区结构。对阳性产物进行基因测序,测序结果在GenBank中进行核酸序列比对检索。结果 289株非重复多重耐药肠杆菌科细菌中有175株(60.55%)检测到Ⅰ类整合酶基因,其中130株具有Ⅰ类整合子可变区基因盒结构,并以dfrA17-aadA5、dfrA15-aadA2、aacA4-catB8-aadA1、aadB-aadA2结构为主;另有35株ISCR1阳性,但仅有5株存在ISCR1可变区基因盒,其结构为qnrA1+ampR、sapA-like-qnrB2等。另有3株菌株发现Ⅰ类整合子和ISCR1基因串联存在于同一菌株。结论 I类整合子及其相关基因盒在肠杆菌科细菌中广泛存在,并存在多种基因盒结构。

Objective To understand the distribution of integrons and insertion sequence common region(ISCR1) of clinically isolated enterobacteriaceae bacteria,and to analyze their related structures.Methods A total of 289 strains of enterobacteriaceae were collected from September 2016 to November 2019.VITEK 2 Compact automatic microbial analyzer was used for bacterial identification.The integrase I gene and ISCR1 gene were amplified by PCR,and the variable region structures of integron and ISCR1 were amplified respectively.Gene sequencing was carried out for the positive products,and the sequencing results were searched by nucleic acid sequence alignment in GenBank.Results Class Ⅰ integrase genes were detected in 175(60.55%) of 289 strains of non-repeat multidrug-resistant enterobacteriaceae,among which 130 strains had class Ⅰ integron variable region gene box structure,mainly composed of dfrA17-aadA5,dfrA15-aadA2,aacA4-catB8-aadAl,aadBaadA2.In addition,there were 35 ISCR1 positive strains,but only 5 strains had ISCR1 variable region gene boxes,whose structures were qnrA1+ampR,sapA-like-qnrB2.Another 3 strains found that class Ⅰ integrons and ISCR1 genes were in tandem in the same strain.Conclusion Class Ⅰ integrons and their related gene boxes are widely existed in enterobacteriaceae,and there are many kinds of gene box structures.