摘要

非典型肠致病性大肠杆菌（aEPEC）是一种新出现的病原体，已引起全球腹泻的爆发。本研究的目的是调查中华人民共和国市场零售食品中aEPEC的发生情况，并研究毒力基因，intimin基因（eae）亚型，多位点序列类型（STs）和抗菌药物敏感性的分离株。 2014年5月至2015年4月，从中国零售市场收集了1200份食品样本，在2.75％（1,200份中的33份）食品样本中检出了41种aEPEC菌株。通常在这些分离株中检测到毒力基因tir，katP，etpD，efa / lifA，ent，nleB和nleE。在分离株中检测到9个eae亚型，其中θ（23个分离株）和β1（6个分离株）最为普遍。通过多位点序列分型将41个分离物分成27个ST。 ST752和ST10是最普遍的。抗生素敏感性试验显示，链霉素（87.80％），头孢噻吩（73.16％），氨苄青霉素（51.22％），四环素（63.42％），甲氧苄氨嘧啶 - 磺胺甲基异恶唑（43.90％）和卡那霉素（43.90％）的分离株具有高抗性。 30株（73.17％）对至少3种抗生素有抗药性，20种（53.66％）对5种或更多抗生素有抗药性。我们的研究结果表明，市场上的零售食品是aEPEC的重要来源。零售食品中存在毒性和多药耐药的aEPEC对消费者构成潜在威胁。在中国强烈建议监测aEPEC污染和谨慎使用抗生素。

Atypical enteropathogenic Escherichia coli (aEPEC) is an emerging pathogen that has been implicated in outbreaks of diarrhea worldwide. The objective of this study was to investigate the occurrence of aEPEC in retail foods at markets in the People's Republic of China and to characterize the isolates for virulence genes, intimin gene ( eae) subtypes, multilocus sequence types (STs), and antimicrobial susceptibility. From May 2014 to April 2015, 1,200 food samples were collected from retail markets in China, and 41 aEPEC isolates were detected in 2.75% (33 of 1,200) of the food samples. The virulence genes tir, katP, etpD, efa/lifA, ent, nleB, and nleE were commonly detected in these isolates. Nine eae subtypes were detected in the isolates, among which θ (23 isolates) and β1 (6 isolates) were the most prevalent. The 41 isolates were divided into 27 STs by multilocus sequence typing. ST752 and ST10 were the most prevalent. Antibiotic susceptibility testing revealed high resistance among isolates to streptomycin (87.80%), cephalothin (73.16%), ampicillin (51.22%), tetracycline (63.42%), trimethoprim-sulfamethoxazole (43.90%), and kanamycin (43.90%). Thirty isolates (73.17%) were resistant to at least three antibiotics, and 20 (53.66 %) were resistant to five or more antibiotics. Our results suggest that retail foods in markets are important sources of aEPEC. The presence of virulent and multidrug-resistant aEPEC in retail foods poses a potential threat to consumers. Surveillance of aEPEC contamination and prudent use of antibiotics is strongly recommended in China.

https://www.ncbi.nlm.nih.gov/pubmed/30277802