树鼩源大肠埃希氏菌耐药性分析与毒力因子鉴定

Analysis of Drug Resistance and Virulence Factors of Escherichia coli in Tree Shrews

为了解树鼩源大肠埃希氏菌遗传进化同源性、对药物的敏感性以及所携带的毒力因子种类等,对广西南宁某大学人工驯化养殖的10只树鼩肠道内容物进行大肠埃希氏菌的分离纯化、生化分析及药敏试验等,并应用PCR技术对菌株进行16S rRNA同源性分析、毒力基因及耐药基因的检测。10份树鼩肠道内容物经分离纯化共分离出9株大肠埃希氏菌。同源性分析表明分离株与鸡源、猪源、人源大肠埃希氏菌之间的亲缘性较近,存在跨种间传播风险。药敏试验表明,分离株对苯唑西林耐药率为88.8%,对氨苄西林耐药率77.8%,对四环素、多西环素耐药率均为44.4%,对头孢哌酮、头孢他啶、卡那霉素、庆大霉素等表现为高度或中度敏感。共扩增出4种耐药基因,分别为四环素类耐药基因tetA、tetB,检出率均为100%,β-内酰胺类耐药基因TEM检出率为100%,CTX-M检出率为44.4%。毒力因子仅检测出eaeA基因,检出率为100%。表明分离株与其他动物源性大肠埃希氏菌亲缘性较近,具有一定耐药性,并携带毒力基因,存在一定的致病风险。

In order to further understand the genetic evolution and pathogenicity of E.coli from tree shrews,including its homology,drug sensitivity and the type of virulence factors it carries,the contents of intestinal tract of tree shrews were isolated and purified for E.coli,the biochemical analysis and drug sensitivity test were conducted,and PCR technology was used to perform 16S rRNA homology analysis,virulence gene and drug resistance gene detection.Nine strains of E.coli were isolated from 10 intestinal contents of tree shrew.Homology analysis showed that the isolates were closely related to E.coli from chicken,pig and human,and there was a risk of cross species transmission.The drug sensitivity test showed that the drug resistance rate of the isolated strains was 88.8%to OXA,77.8%to AMP,44.4%to TET and DOX,and they were highly or moderately sensitive to CFP,CAZ,KAN and GEN.A total of four drug resistance genes were amplified,including tetracycline resistance genes tetA and tetB,with a detection rate of 100%,the detection rate ofβ-lactam resistance gene TEM was 100%,and CTX-M detection rate is 44.4%.The virulence factor only detected the eaeA gene,and the detection rate was 100%.The above results indicated that the isolates are closely related to other animal-derived E.coli,and have certain drug resistance,and carry virulence genes,there is a certain risk of disease.