新疆牛、羊和骆驼源产志贺毒素大肠埃希菌的系统进化分群、血清群与毒力基因及耐药性分析

Phylogenetic Clustering,Serotype,Virulence Genes and Drug Resistance Analysis of Shiga Toxin-producing Escherichia coli from Cattle,Sheep and Camel in Xinjiang

旨在了解新疆牛、羊和骆驼源产志贺毒素大肠埃希菌(Shiga toxin-producing Escherichia coli,STEC)的系统进化分群、血清群、毒力基因、耐药性及其遗传多样性,本研究采用PCR方法对牛、羊和骆驼源STEC进行了系统发育分群、血清群和毒力基因stx 1、stx 2(包括亚型)、eaeA、hlyA检测,通过K-B纸片法对分离株进行药物敏感性检测,并对其进行ERIC-PCR基因分型。结果表明:94株非O157 STEC以B1群为主,含9个血清群,包括O146(n=14)、O22(n=7)、O3(n=4)、O168(n=4)、O8(n=3)、O167(n=2)、O88(n=1)、O112ab(n=1)和O147(n=1)。毒力基因检测显示,46.8%(44/94)仅携带stx 1,6.4%(6/94)仅携带stx 2,46.8%(44/94)同时携带stx 1+stx 2。羊源STEC以携带stx 1+hlyA为主(68.0%);牛源STEC以携带stx 1+stx 2+hlyA为主(57.9%);骆驼源STEC以携带stx 1+hlyA为主(25.0%)。stx 1a主要分布于牛源STEC,stx 1c主要分布于羊源STEC。14株(14.9%)为耐药菌,对头孢他啶、四环素、头孢噻肟、氨苄西林和氨曲南的耐药率为3.2%~5.3%,对复方新诺明、头孢吡肟、哌拉西林-他唑巴坦、氨苄西林-舒巴坦、阿莫西林-克拉维酸和多黏菌素B的耐药率为1.1%~2.1%。ERIC-PCR结果显示牛、羊和骆驼源STEC亲缘关系较近。牛、羊和骆驼携带多种已知血清群STEC,贮存丰富的毒力基因,存在感染人类的风险,应在屠宰加工过程中予以预防和控制。

This study was conducted to examine the distribution of phylogenetic clustering,serotype,virulence genes,drug resistance and genetic diversity of Shiga toxin-producing Escherichia coli(STEC)from cattle,sheep and camel in Xinjiang.Phylogenetic clustering,serotype and virulence genes stx 1,stx 2(including subtypes),eaeA and hlyA of STEC isolates were tested by PCR method from cattle,sheep and camel,drug sensitivity of isolates was determined by using a Kirby-Bauer disk diffusion method and genotypical analysis was performed by enterobacterial repetitive intergenic consensus(ERIC)polymerase chain reaction(PCR).The results showed that 94 of non-O157 STEC isolates which were mainly B1 group and contained 9 serum groups,including O146(n=14),O22(n=7),O3(n=4),O168(n=4),O8(n=3),O167(n=2),O88(n=1),O112ab(n=1)and O147(n=1).The virulence gene test of showed that 46.8%(44/94)carried stx 1 only,6.4%(6/94)for stx 2 only,and 46.8%(44/94)carried both stx 1 and stx 2.STEC isolated from sheep and camel mainly carried stx 1+hlyA(68.0%and 25.0%,respectively),while STEC isolated from cattle mainly carried stx 1+stx 2+hlyA(57.9%).stx 1a was mainly distributed in bovine STEC and stx 1c was mainly distributed in STEC of sheep.Fourteen strains(14.9%)were drug-resistant,and the drug resistance rates of STEC isolates to ceftazidime,tetracycline,cefotaxime,ampicillin and amtronam ranged from 3.2%to 5.3%,to cotrimoxazole,cefepime,piperacillin-tazobactam,ampicillin-sulbactam,amoxicillin-clavulanate and polymyxin B ranged from 1.1%to 2.1%.ERIC-PCR results showed that STEC from cattle,sheep and camel were closely related.Cattle,sheep and camels carry a variety of known serotypes of STEC and store abundant virulence genes,which may potentially infect human beings.Therefore,it is necessary to prevent and control the contamination of meat during slaughtering and processing.