肠出血性大肠埃希菌O157:H7的分布及特征

目的了解H市外环境(食品、生活污水及菜地土壤)中肠出血性大肠埃希菌O157∶H7的分布与特性。方法用免疫磁珠富集法进行O157:H7分离;按《全国食品污染物监测相关实验室手册》(细菌学部分)及相关国家标准鉴定分离菌株;标准血清分型;PCR法测定菌株SLT1,SLT2,ereA,hly毒素基因;纸片琼脂扩散(K-B)法测定菌株耐药性。结果自H市外环境标本(食品、生活污水、菜地土壤)检出O157:H7共15株,检出率1.42%～4.34%,鸡肉与生活污水检出率高;农贸市场食物中O157:H7的检出率(2.25%)高于超市(0.56%);它们中有93.33%(14/15)是携带SLT1、SLT2、eae、hly毒力基因的高致病菌株;食源性O157:H7耐药性严重,耐药菌株多,仅对哌拉西林、亚胺培南敏感。结论H市外环境有O157:H7分布,且检出的多是高致病性强毒菌株,应警惕其流行造成感染的潜在危险。

Objective To analyze Enterohemorrhagic E.coli O157：H7 distribution and characterization in external enviroment（foods, dirty water and soil） of the H city.Methods Collected E.coli O157：H7 by using immunomagnetic sand method .According to the interrelated laboratory manual of nationwie food contaminant monitoriny（ the part of bacteriology） and other correlative government standards, to isolate an identificate the pertinent bacteria in defferent samples, detected the positive specise PCR assay for detection of E.coli O157：H7 was developed with H , O, eae, hly, slt1 and slt2 genes.Applying scrip diffusion method（K-B） to determine the drug resistance of E.coli O157：H7.Results 15 strains of E.coli O157：H7 had been separated from external environment（foods, dirty water and soil）of the H city.The detection rate of E.coli O157：H7（1.42%～4.34%） was the highest in chickens and dirty water.The detection rate of E.coli O157：H7 （2.25%） in form product markets was higher than in supermarkets（0.50%）.The separated E.coli O157：H7 displayed proportional drug resistance with regar to frequently used antibiotics.Conclusion Above mentioned results may provide corresponing scientific evidences for working out strategy about community public heath, foodborne diseases precaution and control.