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Virulence genes in bla(CTX-M) Escherichia coli isolates from chickens and humans

Luke Randall1, Guanghui Wu, Neil Phillips

  • 1Veterinary Laboratories Agency (Weybridge), Department of Bacteriology, New Haw, Addlestone, Surrey KT15 3NB, United Kingdom. l.randall@vla.defra.gsi.gov.uk

Research in Veterinary Science
|July 15, 2011
PubMed

Insights

CTX-M Escherichia coli strains from chickens and humans share some virulence genes, but distinct sets are found in each host. Genes associated with chicken disease were also present in healthy birds, indicating complex transmission dynamics.

Area of Science:

  • Microbiology
  • Genetics
  • Veterinary Medicine

Background:

  • CTX-M producing Escherichia coli (E. coli) are significant pathogens in both human and animal health.
  • Understanding the distribution of virulence factors in E. coli is crucial for assessing disease potential and transmission.
  • Colibacillosis, caused by E. coli, is a common disease in poultry, while E. coli is a leading cause of human urinary tract infections.

Purpose of the Study:

  • To investigate the presence and distribution of virulence genes in CTX-M E. coli isolates from diseased chickens, healthy chickens, and human urinary tract infections.
  • To compare the genetic profiles of E. coli strains across different hosts and health statuses.

Main Methods:

  • Utilized microarray technology to screen for 56 different virulence genes in E. coli isolates.
  • Determined blaCTX-M sequence type and replicon type for strains from diseased poultry.
  • Compared gene presence/absence across isolates from diseased poultry, healthy poultry, and human UTIs.

Main Results:

  • Virulence genes found in diseased chickens, including astA and tsh, were also detected in healthy chicken isolates.
  • A significant proportion (6/10) of identified virulence genes were exclusive to human UTI isolates.
  • Distinct sets of virulence genes were identified as exclusive to either chicken or human E. coli isolates, such as ireA and lpfA in chickens, and ctdB and nfaE in humans.

Conclusions:

  • CTX-M E. coli strains from chickens generally differ from those causing human infections.
  • The presence of certain virulence genes in both diseased and healthy chickens suggests a complex reservoir and potential for adaptation.
  • Findings highlight host-specific adaptations in virulence gene profiles of CTX-M E. coli.

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