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

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

JOURNAL=Frontiers in Veterinary Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2021.574801

DOI=10.3389/fvets.2021.574801

ISSN=2297-1769

ABSTRACT=<p>The bovine <italic>Escherichia coli</italic> 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 <italic>E. coli</italic> O157:H7. We investigated the antibiotic resistance, molecular profiles, and intrinsic relationship between 21 isolates of <italic>E. coli</italic> 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 <italic>eae</italic> gene, and 7 (33%) carried the <italic>stx1</italic> + <italic>stx2</italic> + <italic>eae</italic> + <italic>hly</italic> + <italic>tccp</italic> 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 <italic>bla</italic><sub>CTX−M−121</sub> gene. This is the first finding of the <italic>bla</italic><sub>CTX−M−121</sub> gene detected in <italic>E. coli</italic> O157:H7 isolated from cattle in Xinjiang. The <italic>bla</italic><sub>CTX−M−121</sub> gene is transferable between the bacterial strains via plasmid transmission. The results indicated that <italic>E. coli</italic> O157:H7 may have undergone clonal propagation in cattle population and cross-regional transmission in Xinjiang, China.</p>