Characteristics of clinical Shiga toxin-producing Escherichia coli isolated from British Columbia

Biomed Res Int. 2013:2013:878956. doi: 10.1155/2013/878956. Epub 2013 Oct 2.

Abstract

Shiga toxin-producing Escherichia coli (STEC) are significant public health threats. Although STEC O157 are recognized foodborne pathogens, non-O157 STEC are also important causes of human disease. We characterized 10 O157:H7 and 15 non-O157 clinical STEC derived from British Columbia (BC). Eae, hlyA, and stx were more frequently observed in STEC O157, and 80 and 100% of isolates possessed stx₁ and stx₂, respectively. In contrast, stx₁ and stx₂ occurred in 80 and 40% of non-O157 STEC, respectively. Comparative genomic fingerprinting (CGF) revealed three distinct clusters (C). STEC O157 was identified as lineage I (LI; LSPA-6 111111) and clustered as a single group (C1). The cdi gene previously observed only in LII was seen in two LI O157 isolates. CGF C2 strains consisted of diverse non-O157 STEC while C3 included only O103:H25, O118, and O165 serogroup isolates. With the exception of O121 and O165 isolates which were similar in virulence gene complement to STEC O157, C1 O157 STEC produced more Stx2 than non-O157 STEC. Antimicrobial resistance (AMR) screening revealed resistance or reduced sensitivity in all strains, with higher levels occurring in non-O157 STEC. One STEC O157 isolate possessed a mobile bla(CMY-2) gene transferrable across genre via conjugation.

MeSH terms

  • Adhesins, Bacterial / genetics
  • British Columbia
  • DNA Fingerprinting
  • DNA, Bacterial / genetics
  • DNA, Bacterial / isolation & purification
  • Drug Resistance, Bacterial / genetics
  • Escherichia coli Infections / microbiology
  • Escherichia coli O157 / genetics
  • Escherichia coli O157 / isolation & purification
  • Escherichia coli O157 / pathogenicity
  • Escherichia coli Proteins / genetics
  • Genes, Bacterial
  • Hemolysin Proteins / genetics
  • Humans
  • Serotyping
  • Shiga Toxin 1 / genetics
  • Shiga Toxin 2 / genetics
  • Shiga-Toxigenic Escherichia coli / genetics
  • Shiga-Toxigenic Escherichia coli / isolation & purification*
  • Shiga-Toxigenic Escherichia coli / pathogenicity
  • Virulence / genetics

Substances

  • Adhesins, Bacterial
  • DNA, Bacterial
  • Escherichia coli Proteins
  • Hemolysin Proteins
  • Hlya protein, E coli
  • Shiga Toxin 1
  • Shiga Toxin 2
  • eaeA protein, E coli