Zhang Shuhong, Wu Qingping, Zhang Jumei, Zhu Xuemei
1 Guangdong Institute of Microbiology , Guangzhou, China .
2 State Key Laboratory of Applied Microbiology , Guangzhou, South China.
Foodborne Pathog Dis. 2016 Jan;13(1):49-55. doi: 10.1089/fpd.2015.2020. Epub 2015 Nov 17.
Enteropathogenic Escherichia coli (EPEC) is an important foodborne pathogen that potentially causes infant and adult diarrhea. The occurrence and characteristics of EPEC in retail ready-to-eat (RTE) foods have not been thoroughly investigated in China. This study aimed to investigate EPEC occurrence in retail RTE foods sold in the markets of China and to characterize the isolated EPEC by serotyping, virulence gene analyses, antibiotic susceptibility test, and molecular typing based on enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). From May 2012 to April 2013, 459 RTE food samples were collected from retail markets in 24 cities of China. E. coli in general, and EPEC specifically, were detected in 144 (31.4%) and 39 (8.5%) samples, respectively. Cold vegetable in sauce was the food type most frequently contaminated with EPEC (18.6%). Of 39 EPEC isolates, 38 were atypical EPEC (eae+) and 1 was typical EPEC (eae+bfpA+) by multiplex PCR assays. The virulence genes espA, espB, tir, and iha were detected in 12, 9, 2, and 1 of 39 isolates, respectively, while genes toxB, etpD, katP, and saa were not detected. O-antigen serotyping results showed that among 28 typeable isolates, the most common serotype was O119, followed by O26, O111, and O128. Many isolates were resistant to tetracycline (64.1%; 25/39), ampicillin (48.7%; 19/39), and trimethoprim/sulfamethoxazole (48.7%; 19/39). ERIC-PCR indicated high genetic diversity in EPEC strains, which classified 42 strains (39 isolates and 3 reference strains) into 32 different profiles with a discrimination index of 0.981. The findings of this study highlight the need for close surveillance of the RTE foods at the level of production, packaging, and storage to minimize risks of foodborne disease.
肠致病性大肠杆菌（EPEC）是一种重要的食源性病原体，可能导致婴幼儿和成人腹泻。在中国，即食（RTE）零售食品中EPEC的发生情况和特征尚未得到充分研究。本研究旨在调查中国市场上销售的零售即食食品中EPEC的发生情况，并通过血清分型、毒力基因分析、药敏试验以及基于肠杆菌重复基因间共识聚合酶链反应（ERIC-PCR）的分子分型对分离出的EPEC进行特征分析。2012年5月至2013年4月，从中国24个城市的零售市场采集了459份即食食品样本。总体大肠杆菌和特定的EPEC分别在144份（31.4%）和39份（8.5%）样本中被检测到。酱汁凉拌蔬菜是最常被EPEC污染的食品类型（18.6%）。通过多重PCR检测，39株EPEC分离株中，38株为非典型EPEC（eae+），1株为典型EPEC（eae+bfpA+）。在39株分离株中，分别有12株、9株、2株和1株检测到毒力基因espA、espB、tir和iha，而未检测到toxB、etpD、katP和saa基因。O抗原血清分型结果显示，在28株可分型分离株中，最常见的血清型是O119，其次是O26、O111和O128。许多分离株对四环素（64.1%；25/39）、氨苄青霉素（48.7%；19/39）和甲氧苄啶/磺胺甲恶唑（48.7%；19/39）耐药。ERIC-PCR表明EPEC菌株具有高度的遗传多样性，将42株菌株（39株分离株和3株参考菌株）分为32种不同的图谱，鉴别指数为0.981。本研究结果强调了在生产、包装和储存层面密切监测即食食品以降低食源性疾病风险的必要性。
