大肠埃希菌尿液分离株可移动遗传元件研究

目的调查大肠埃希菌尿液分离株中质粒、转座子和整合子等可移动遗传元件的存在情况。方法收集宁波市第一医院2008年10月～2009年3月患者尿液标本中分离的大肠埃希菌共28株,采用聚合酶链反应(PCR)及序列分析的方法分析10种可移动遗传元件:traA、trbC、tnpA、tnpU、tnp513、tnsA、merA、intⅠ1、intⅠ2、intⅠ3。结果28株大肠埃希菌共检出3种基因:traA、trbC、intⅠ1,其余7种基因未检出;各种基因阳性率以traA最高25株(89.3%),intⅠ1次之19株(67.9%),trbC8株(28.6%);所有28株(100.0%)至少检出1种基因,各菌株基因阳性数1～3种,5株ECO同时检出3种基因,13株同时检出2种基因,10株仅检出1种基因。结论同时检测10种可移动遗传元件是国内首次报道,traA和intⅠ1基因阳性率较高,而trbC基因阳性率较低;可移动遗传元件介导各种耐药基因使受体菌表现为多药耐药,检出trbC基因为国内首次报道。

Mobile Genetic Elements in Multi-drug Resistant Strains of Escherichia coli Isolated from Urine

OBJECTIVE To investigate the distribution of mobile genetic elements:plasmids,transposons,and integrons in multi-drug resistant strains of Escherichia coli isolated from urine.METHODS From Oct 2008 to Mar 2009,28 multi-drug resistant strains of E.coli isolated from urine were collected from Ningbo No.1 Hospital,China.Then,10 kinds of mobile genetic elements(traA,trbC,tnpA,mpU,tnp513,tnsA,merA,int I 1,int I 2,and int I 3)were analyzed by PCR and verified by DNA sequencing.RESULTS In 28 strains of E.coli,25 strains(89.3%),19 strains(67.9%)and 7 strains(25.0%)were detected to carry traA,int I 1 and trbC,respectively.However,the other 7 kinds of genes couldn't be detected out.Furthermore,all 28 strains(100.0%)were detected to carry at least 1 kind of gene.In addition,5 strains were detected to carry 3 kinds of genes,13 strains were detected to carry 2 kinds of genes,and 10 strains were detected to carry 1 kind of gene.CONCLUSIONS It's the first report to detect 10 kinds of mobile genetic elements in China.The positive rate of traA and int I 1 carryed on 28 multi-drug resistant strains of E coli are much higher than that of trbC.And acquired resistance genes induced by mobile genetic elements cause the recipient strains to express multi-drug resistance.Moreover,it's the first report that trbC is detected in China.