Evaluation of animal genetic and physiological factors that affect the prevalence of Escherichia coli O157 in cattle

PLoS One. 2013;8(2):e55728. doi: 10.1371/journal.pone.0055728. Epub 2013 Feb 6.

Abstract

Controlling the prevalence of Escherichia coli O157 in cattle at the pre-harvest level is critical to reduce outbreaks of this pathogen in humans. Multilayers of factors including the environmental and bacterial factors modulate the colonization and persistence of E. coli O157 in cattle that serve as a reservoir of this pathogen. Here, we report animal factors contributing to the prevalence of E. coli O157 in cattle. We observe the lowest number of E. coli O157 in Brahman breed when compared with other crosses in an Angus-Brahman multibreed herd, and bulls excrete more E. coli O157 than steers in the pens where cattle were housed together. The presence of super-shedders, cattle excreting >10(5) CFU/rectal anal swab, increases the concentration of E. coli O157 in the pens; thereby super-shedders enhance transmission of this pathogen among cattle. Molecular subtyping analysis reveal only one subtype of E. coli O157 in the multibreed herd, indicating the variance in the levels of E. coli O157 in cattle is influenced by animal factors. Furthermore, strain tracking after relocation of the cattle to a commercial feedlot reveals farm-to-farm transmission of E. coli O157, likely via super-shedders. Our results reveal high risk factors in the prevalence of E. coli O157 in cattle whereby animal genetic and physiological factors influence whether this pathogen can persist in cattle at high concentration, providing insights to intervene this pathogen at the pre-harvest level.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Shedding / physiology*
  • Cattle / genetics*
  • Cattle Diseases / epidemiology*
  • Cattle Diseases / microbiology
  • Cattle Diseases / transmission
  • Colony Count, Microbial
  • DNA, Bacterial / genetics
  • Escherichia coli Infections / epidemiology*
  • Escherichia coli Infections / microbiology
  • Escherichia coli Infections / veterinary
  • Escherichia coli O157 / physiology*
  • Female
  • Male
  • Polymerase Chain Reaction
  • Prevalence

Substances

  • DNA, Bacterial

Grants and funding

This work was supported by the Institute of Food and Agricultural Sciences, and Emerging Pathogens Institute at University of Florida, grants to KCJ. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.