Factors associated with Shiga toxin-producing Escherichia coli shedding by dairy and beef cattle

Cristina Venegas-Vargas, Scott Henderson, Akanksha Khare, Rebekah E. Mosci, Jonathan D. Lehnert, Pallavi Singh, Lindsey M. Ouellette, Bo Norby, Julie A. Funk, Steven Rust, Paul C. Bartlett, Daniel Grooms, Shannon D. Manning

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen that can cause hemorrhagic colitis and hemolytic- uremic syndrome. Cattle are the primary reservoir for STEC, and food or water contaminated with cattle feces is the most common source of infections in humans. Consequently, we conducted a cross-sectional study of 1,096 cattle in six dairy herds (n ± 718 animals) and five beef herds (n ± 378 animals) in the summers of 2011 and 2012 to identify epidemiological factors associated with shedding. Fecal samples were obtained from each animal and cultured for STEC. Multivariate analyses were performed to identify risk factors associated with STEC positivity. The prevalence of STEC was higher in beef cattle (21%) than dairy cattle (13%) (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.25, 2.47), with considerable variation occurring across herds (range, 6% to 54%). Dairy cattle were significantly more likely to shed STEC when the average temperature was>28.9°C 1 to 5 days prior to sampling (OR, 2.5; 95% CI, 1.25, 4.91), during their first lactation (OR, 1.8; 95% CI, 1.1, 2.8), and when they were<30 days in milk (OR, 3.9; 95% CI, 2.1, 7.2). These data suggest that the stress or the negative energy balance associated with lactation may result in increased STEC shedding frequencies in Michigan during the warm summer months. Future prevention strategies aimed at reducing stress during lactation or isolating high-risk animals could be implemented to reduce herdlevel shedding levels and avoid transmission of STEC to susceptible animals and people.

Original languageEnglish (US)
Pages (from-to)5049-5056
Number of pages8
JournalApplied and environmental microbiology
Issue number16
StatePublished - 2016
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Ecology
  • Applied Microbiology and Biotechnology


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