猪源大肠埃希菌分离鉴定、耐药性、致病性研究及噬菌体分离

Isolation and identification of swine E.coli,drug resistance and pathogenicity,and phage isolation

大肠埃希菌是引起仔猪腹泻常见的细菌病原体。本实验以山东省聊城市产房腹泻仔猪为研究对象,采集腹泻仔猪粪便,通过对细菌分离、纯化,经16s rDNA基因扩增及全基因组测序,最后确诊为大肠埃希菌,该菌株全基因组序列的全长为4584108 bp;并对分离到的大肠埃希菌进行药敏试验、耐药及毒力基因检测、小鼠致病力试验及对应的噬菌体分离纯化。结果表明,该大肠埃希菌为O11血清型,主要耐药基因为blaSHV、blaTEM、aadA1、sul1、tetA;主要毒力基因为fyuA、ler;对阿奇霉素、丁胺卡那、新霉素敏感,对头孢氨苄、阿莫西林、四环素类抗生素严重耐药;对小鼠致病力强(109 CFU/mL);同时,分离纯化了5株对应的大肠埃希菌噬菌体,为大肠埃希菌的多重防控提供理论依据。

Escherichia coli is a common bacterial pathogen that causes piglet diarrhea.In this study,the feces of diarrheal piglets in the delivery room of Liaocheng City,Shandong Province were collected.Through the isolation and purification of bacteria,16s rDNA gene amplification and whole genome sequencing,Escherichia coli was finally diagnosed.The whole genome sequence length of this strain was 4 584 108 bp.Drug susceptibility test,drug resistance and virulence gene test,pathogenicity test of mice and corresponding phage isolation and purification were carried out on isolated Escherichia coli.The drug susceptibility test,virulence gene test,mouse pathogenicity test and phage isolation were carried out.The results showed that the E.coli was serotype O11 and the main resistance genes were blaSHV,blaTEM,aadA1,sul1 and tetA.The main virulence genes were fyuA and ler.It was sensitive to azithromycin,butamicana and neomycin,which was seriously resistant to cephalexin,amoxicillin and tetracycline antibiotics.It was highly pathogenic to mice(10~9 CFU/mL).At the same time,5 corresponding E.coli phages were isolated and purified,which provided theoretical basis for multiple prevention and control of E.coli.