Genetic & virulence profiling of ESBL-positive E. coli from nosocomial & veterinary sources

J M Tyrrell, M Wootton, M A Toleman, R A Howe, M Woodward, T R Walsh

Research output: Contribution to journalArticle (Academic Journal)

Abstract

CTX-M genes are the most prevalent ESBL globally, infiltrating nosocomial, community and environmental settings. Wild and domesticated animals may act as effective vectors for the dissemination of CTX-producing Enterobacteriaceae. This study aimed to contextualise blaCTX-M-14-positive, cephalosporin-resistant Enterobacteriaceae human infections and compared resistance and pathogenicity markers with veterinary isolates. Epidemiologically related human (n=18) and veterinary (n=4) blaCTX-M-14-positive E. coli were fully characterised. All were typed by XbaI pulsed field gel electrophoresis and ST. Chromosomal/plasmidic locations of blaCTX-M-14 were deduced by S1-nuclease digestion, and association with ISEcp1 was investigated by sequencing. Conjugation experiments assessed transmissibility of plasmids carrying blaCTX-M-14. Presence of virulence determinants was screened by PCR assay and pathogenicity potential was determined by in vitro Galleria mellonella infection models. 84% of clinical E. coli originated from community patients. blaCTX-M-14 was found ubiquitously downstream of ISEcp1 upon conjugative plasmids (25-150 kb). blaCTX-M-14 was also found upon the chromosome of eight E. coli isolates. CTX-M-14-producing E. coli were found at multiple hospital sites. Clonal commonality between patient, hospitals and livestock microbial populations was found. In vivo model survival rates from clinical isolates (30%) and veterinary isolates (0%) were significantly different (p<0.05). Co-transfer of blaCTX-M-14 and virulence determinants was demonstrated. There is evidence of clonal spread of blaCTX-M-14-positive E. coli involving community patients and farm livestock. blaCTX-M-14 positive human clinical isolates carry a lower intrinsic pathogenic potential than veterinary E. coli highlighting the need for greater veterinary practices in preventing dissemination of MDR E. coli among livestock.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalVeterinary Microbiology
Volume186
DOIs
Publication statusPublished - 15 Apr 2016

Bibliographical note

Copyright © 2016. Published by Elsevier B.V.

Keywords

  • Animals
  • Conjugation, Genetic
  • Cross Infection/microbiology
  • Drug Resistance, Bacterial/genetics
  • Escherichia coli/classification
  • Escherichia coli Infections/microbiology
  • Humans
  • Plasmids/genetics
  • Virulence/genetics

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