自贡地区艾伯特埃希菌的筛查及菌株特征分析

Prevalence and characteristics of Escherichia albertii in Zigong, China

目的 了解自贡地区人群、动物源性食品、家禽及鸟类携带艾伯特埃希菌情况及菌株特征.方法 采集市售牛肉、羊肉、猪肉、鸡肉、鸭肉、鸭肠及鸡肠,不同鸟类粪便及腹泻患者和密切接触人群粪便,经EC肉汤增菌后,PCR检测eae基因,阳性增菌液接种麦康凯琼脂,挑取不发酵乳糖、eae阳性菌落进一步通过16S rDNA测序及多位点序列分型分析（MLST）,确定为艾伯特埃希菌,并对菌株进行eae、cdtB多态性分析及脉冲场凝胶电泳（PFGE）分型分析.结果 本研究共鉴定51株艾伯特埃希菌（19株来源于鸭肠及其内容物、18株来源于鸡肠及其内容物、3株来源于腹泻患者粪便、3株来源于密切接触人群粪便、1株来源于白鹭粪便、3株来源于鸡肉、2株来源于鸭肉、1株来源于猪肉、1株来源于羊肉）.eae分为6种亚型,分别为sigma、rho、iota2、epsilon3,nu及N5,而51株艾伯特埃希菌均具有Ⅱ/Ⅲ/ⅤcdtB亚型,其中3株菌同时具有Ⅰ/ⅣcdtB亚型.51株分离株共分为40种PFGE带型,呈多态性分布.结论 首次在中国腹泻患者、密切接触人群、野生白鹭、家禽和动物源性食品中证实了艾伯特埃希菌的存在,对进一步深入开展艾伯特埃希菌病原学、流行病学研究具有重要实际意义.

Objective To study the prevalence and characteristics of a new pathogen Escherichia albertii in human , animal - derived food , poultry and birds in Zigong city , Sichuan province . Methods Samples of beef, mutton, pork, chicken, duck, chicken intestine, duck intestine and birds′droppings were collected from markets and stool samples of diarrheal patients and their close contacts were collected from hospitals. The samples were enriched with EC broth and tested for the presence of eae gene by PCR. Each eae-positive enrichment culture was streaked on MacConkey agar. The eae-positive non-lactose fermenting strains were identified as Escherichia albertii by 16S rDNA sequencing and housekeeping genes analysis. Those strains were further analyzed by intimin and cdtB subtyping and pulsed-field gel electrophoresis （ PFGE） . Results Fifty-one strains were identified as Escherichia albertii, including 19 from duck intes-tines, 18 from chicken intestines, 3 from diarrheal patients, 3 from close contacts, 1 from egret excrement, 3 from chicken meat, 2 from duck meat, 1 from pork and 1 from mutton. Six intimin subtypes （ sigma, rho, iota2, epsilon3, nu and N5） were harbored by those strains. All 51 strains carried the Ⅱ/Ⅲ/Ⅴ subtype group of cdtB and among them, 3 strains possessed another copy of Ⅰ/Ⅳ subtype group. Results of PFGEshowed high genetic diversity with 40 different band patterns. Conclusion It is the first time that Escherich-ia albertii was identified in diarrheal patients, close contacts, egret, poultry and animal-derived food in Chi-na. It is practically important for understanding the etiology and epidemiology of Escherichia albertii in China.