Epidemiological survey on Escherichia coli O157 in Chongqing and Three-Gorge Reservoir Areas of China

  • Haoju Wang
  • Xuhu Mao
  • Honglei Ding
  • Quanming Zou
  • Xiao Peng
Original Article

DOI: 10.1007/s11259-008-9048-8

Cite this article as:
Wang, H., Mao, X., Ding, H. et al. Vet Res Commun (2008) 32: 449. doi:10.1007/s11259-008-9048-8

Abstract

Prevalence, presence of virulence and adherence associated genes, genetic diversity, biochemical characteristics, and antibiotic susceptibility were determined for Escherichia coli O157 isolated over 4 months in Chongqing city and Three-Gorge Reservoir Areas. 11 isolates of E. coli O157 were isolated from 1504 samples and 7 of them are O157:H7 and 4 are O157:H? All O157:H7 isolates had eaeA, ehxA, EspA and Tccp genes, but did not have stx1 and stx2. All O157:H? isolates did not have stx1, stx2, eaeA, ehxA, EspA and Tccp genes except for the isolate obtained from Yunyang county which had stx1. When eaeA and ehxA presented in isolates were digested by restriction enzymes, the numbers and the sizes of the segments were the same as the control E. coli O157 strains. This suggests that eaeA and ehxA exhibit poor polymorphism. Most E. coli O157 isolates showed identical biochemical activities to the standard strains for sorbitol and rhamnose, and all E. coli O157:H7 obtained from feces at the same dairy cattle farm had similar biochemical characteristics. Antibiotic susceptibility demonstrated resistance of the isolates to penicillin, ampicillin, bacitracin, cefuroxime, erythromycin, gentamycin and tetracycline, indicating the isolates obtained in this study had a multi-drug resistance.

Keywords

Escherichia coli O157 Genetic analysis Phenotypic characteristics Polymorphism Three-Gorge Reservoir Area 

Abbreviations

eaeA

attaching-and-effacing gene A subunit

EHEC

enterohaemorrhagic Escherichia coli

ehxA

enterohemolysin gene A subunit

EspA

E. coli secreted protein A subunit

HC

hemorrhagic colitis

HUS

hemolytic-uremic syndrome

mEC+n

modified E.coli broth supplemented containing 20 mgl–1 novobiocin

PCR-RFLP

polymerase chain reaction-restriction fragment length polymorphism

stx

Shiga toxin

STEC

Shiga toxin-producing Escherichia coli

Tccp

Tir to the actin-cytoskeleton

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Haoju Wang
    • 1
  • Xuhu Mao
    • 2
  • Honglei Ding
    • 1
  • Quanming Zou
    • 2
  • Xiao Peng
    • 3
  1. 1.Key Laboratory of Grazing and Domestic Grazing Animals of Chongqing, College of Animal Science and TechnologyUniversity of SouthwestChongqingChina
  2. 2.Chongqing Engineering Technology Research Center of Biopharmaceuticals & Institution of Clinical Microbiology and ImmunologyThird Military Medical UniversityChongqingChina
  3. 3.Chongqing Zhengda Limited CompanyChongqingChina