Frontiers in Veterinary Science (May 2021)

First Isolation and Molecular Characterization of blaCTX-M-121-Producing Escherichia coli O157:H7 From Cattle in Xinjiang, China

  • Zhanqiang Su,
  • Panpan Tong,
  • Ling Zhang,
  • Mengmeng Zhang,
  • Dong Wang,
  • Kaiqi Ma,
  • Yi Zhang,
  • Yingyu Liu,
  • Lining Xia,
  • Jinxin Xie

DOI
https://doi.org/10.3389/fvets.2021.574801
Journal volume & issue
Vol. 8

Abstract

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The bovine Escherichia coli O157:H7 is a major foodborne pathogen causing severe bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome in humans. Cattle are recognized major reservoir and source of E. coli O157:H7. We investigated the antibiotic resistance, molecular profiles, and intrinsic relationship between 21 isolates of E. coli O157:H7 from cattle farms and slaughtering houses in Xinjiang. Using pulsed-field gel electrophoresis (PFGE) molecular typing, two types of PFGE were revealed through cluster analysis, including clusters I and II, with 66 and 100% similarity of PFGE spectra between 21 isolates. We also detected that 18 isolates (86%) carried at least one virulence gene, 16 isolates (76%) carried the eae gene, and 7 (33%) carried the stx1 + stx2 + eae + hly + tccp genes. Eighteen isolates were susceptible to antibiotics. Three isolates were resistant to antibiotics, and two were multidrug resistant. One of the two multidrug-resistant isolates detectably carried the blaCTX−M−121 gene. This is the first finding of the blaCTX−M−121 gene detected in E. coli O157:H7 isolated from cattle in Xinjiang. The blaCTX−M−121 gene is transferable between the bacterial strains via plasmid transmission. The results indicated that E. coli O157:H7 may have undergone clonal propagation in cattle population and cross-regional transmission in Xinjiang, China.

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