朱鹮源大肠埃希氏菌分离鉴定及耐药性与致病性研究

Isolation,Identification,Drug Resistance and Pathogenicity of Escherichia coli from Crested Ibis

为分析陕西楼观台朱鹮源大肠埃希氏菌携带情况,无菌采集朱鹮咽拭子和肛拭子进行细菌分离鉴定,成功从肛拭子中分离到一株疑似大肠埃希氏菌菌株,对分离菌株进行生化试验、16S rRNA测序鉴定、药敏试验、耐药基因鉴定、毒力基因鉴定及小鼠致病性试验。经鉴定该菌株为大肠埃希氏菌,命名为XNZH1,该菌株对氧氟沙星、安普霉素、大观霉素、四环素和氟苯尼考耐药,携带耐药基因sul2和毒力基因etrA。小鼠致病性试验结果显示,经腹腔接种的6只小鼠均在接种后18 h内死亡,且从脑组织中分离到该菌,推测该菌可穿过血脑屏障。进化树分析表明,该菌株与分离株MH532531.1同源性高达98%。试验结果表明朱鹮源大肠埃希氏菌具有高度耐药性和致病性,结果可为朱鹮大肠埃希氏菌病的防控及合理用药提供依据。

In order to analyze the carriage of E.coli from crested ibis source in Louguantai,Shaanxi,this experiment aseptically collected pharyngeal swabs and anal swabs from crested ibis for bacterial isolation and identification,and successfully isolated a suspected Escherichia coli strain from the anal swab,and conducted biochemical tests,16S rRNA sequencing identification,drug sensitivity test,drug resistance gene identification,virulence gene identification and mouse pathogenicity test on the isolated strain.The strain was identified as E.coli,named XNZH1,which was resistant to ofloxacin,ampicillin,daikonomycin,tetracycline and florfenicol,and carried resistance gene sul2 and virulence gene etrA.The pathogenicity test in mice showed that all six mice inoculated intraperitoneally died within 18 h after inoculation,and the bacterium was isolated from brain tissue,which was presumed to be able to cross the blood-brain barrier.The phylogenetic tree analysis showed that the strain was highly homologous to the isolate MH532531.1,reaching 98%.The results of this experiment indicated that E.coli of crested ibis origin is highly resistant and pathogenic,and the results can provide a basis for the prevention and control of colibacillosis and rational drug use in crested ibis.