Virulence and Antimicrobial Characteristics of Escherichia Coli Isolated from Diseased Chickens in China and Algeria

Junwei Wang,Lounis Mohamed,Zhigang Cui,Juan Wang,Shigan Yan,Hefei Xu,Zhina Qu,Ge Zhao,Jianmei Zhao,Wenyan Gai,Yubin Gao,Ming Zou

doi:10.24297/jaa.v10i0.8425

Abstract

To reveal and compare the prevalence of pathotypes and virulence genes, as well as antimicrobial resistance and genotyping of poultry E. coli isolates from China and Algeria. Pathotype and seven virulence genes were tested by PCR, susceptibility to antimicrobials was evaluated using broth microdilution method, and genotyping was analyzed by PFGE. Six isolates were identified as pathogenic E. coli. Virulence gene testing showed that the frequency of ompT, iss, fimC, iroN, hlyF and iutA was high in the isolates from Shandong, Shanxi, Jiangsu and Xinjiang province, while stx2 was detected in only two isolates from Shandong, and stx2, iss, fimC, hlyF and iutA could not be detected in Tibet isolates. Importantly, nearly all isolates from Algeria carried seven virulence genes. Drug resistance testing of 141 strains showed that 98.2% (109/111) of the isolates from China and all isolates (30/30) from Algeria resist to more than three classes of antimicrobials. The PFGE genotyping of 157 isolates yielded 134 types, demonstrated a high level of genetic diversity among these isolates. Thus, the poultry E. coli from both China and Algeria exhibited either high frequencies of antimicrobial resistance or high rates of virulence genes carrying.

Highlights

Escherichia coli (E. coli) is a member of the normal flora in human and warm-blooded animal intestinal tracts
In order to study the prevalence of pathogenic E. coli, we categorized the E. coli isolates into different pathothypes according to the PCR results for pathogenic marker genes: eae, stx, est, elt, ipaH, and aggR
Six (2.42%, 6/248) isolates were identified as pathogenic E. coli which carried est and/or elt gene, and all these pathogenic strains were classified as enterotoxigenic E. coli (ETEC)

Summary

Introduction

Escherichia coli (E. coli) is a member of the normal flora in human and warm-blooded animal intestinal tracts. Some E. coli strains are usually pathogenic and have virulence properties that may cause animal diarrhea, hemorrhagic colitis and hemolytic uremic syndrome [1]. Five kinds of E. coli pathotype are widely recognized that may cause colibacillosis both in human and animals according to their specific virulence gene, pathogenic mechanism and genetic features: enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC) and enteroaggregative E. coli (EAEC) [2]. The pathogenic E. coli generally possesses rich virulence genes that displayed during disease happening. Many clinical isolated E. coli strains from diseased or dead chickens may carried abundant virulence genes but cannot attribute to any pathotype

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