新疆部分地区牛羊源产志贺毒素大肠埃希菌菌株检测与分析

产志贺毒素大肠埃希菌（Shiga toxin-producing Escherichia coli，STEC）是一类携带了前噬菌体编码的一种或两种志贺毒素基因的新发高致病性食源性病原菌，已成为威胁人类健康的重要公共卫生问题。为了解新疆部分地区牛、羊源各个环节产志贺毒素大肠埃希菌的感染情况及其遗传多样性，以及分离株对17种常见抗生素的敏感性，笔者采用PCR方法对STEC分离株进行了4种毒力基因（stx1、stx2、eae、hlyA）的检测和ERIC-PCR基因分型研究。结果表明：从屠宰场、养殖场和市场共431份样品中分离出产志贺毒素的大肠埃希菌64株，其中，编码stx1+stx2的STEC有31株（48.4%），只编码stx1的STEC有29株（45.3%），只编码stx2的STEC有4株（6.3%），4种毒力基因同时存在的有1株。药物敏感性检测发现STEC菌株对麦迪霉素（61%）、头孢噻吩（4.7%）、头孢西丁（4.7%）、氨苄西林（3.1%）、哌拉西林（1.6%）、妥布霉素（1.6%）、头孢唑啉（1.6%）等7种抗生素存在耐药。ERIC-PCR检测结果呈多态性分布，分为A（36株）和B（28株）两个簇。STEC菌株在新疆部分地区牛、羊源各个环节被检出，其中一些菌株可能会增加对食物的污染，从而引起人发病。

Detection and Analysis of Shiga Toxin-producing Escherichia coli Isolates from Cattle and Sheep Sources in Some Regions of Xinjiang,China

Shiga toxin-producing Escherichia coli(STEC) is a new class of highly pathogenic food-borne pathogens carrying a prephage encoding one or two Shiga toxin genes. It has become an important public health issue that threatens human health. The present work aimed to characterize STEC strains isolated from cattle and sheep at various stages, in parts of Xinjiang, in terms of the presence of prevalence, genetic diversity, and antimicrobial susceptibility to 17 common antibiotics. Through amplification of four virulence genes (stx1, stx2, eae, hlyA)by PCR and ERIC-PCR genotyping to detection STEC isolates. In the present study, a total of 64 STEC strains were isolated from 431 samples from slaughterhouses, farms and markets. Of these, 31 (48.4%) of the isolates harbored stx1 + stx2, and only 29 (45.3%) of the isolates possessed stx1, only 4 (6.3%) of the isolates harbored stx2, and 1 isolates harbored all the 4 virulence genes. Drug sensitivity tests found that STEC strains displayed 7 antimicrobial resistance to midecamycin(61%), cephalothin(4.7%), cefoxitin(4.7%), ampicillin(3.1%), piperacillin(1.6%), tobramycin(1.6%), cefazolin(1.6%). The ERIC-PCR results showed a polymorphic distribution, which was divided into two clusters of A (36 strains) and B (28 strains). STEC strains isolated from cattle and sheep at various stages, in parts of Xinjiang, some of which might have the potential to cause food contamination and human diseases.