Abstract
Escherichia coli O157:H7 fecal shedding in feedlot cattle is common and is a public health concern due to the risk of foodborne transmission that can result in severe, or even fatal, disease in people. Despite a large body of research, few practical and cost-effective farm-level interventions have been identified. In this study, a randomized controlled trial was conducted to assess the effect of reducing the level of water in automatically refilling water-troughs on fecal shedding of E. coli O157:H7 in feedlot cattle. Pens in a feedlot in the Texas Panhandle were randomly allocated as control (total number: 17) or intervention (total number: 18) pens. Fecal samples (2,759 in total) were collected both at baseline and three weeks after the intervention, and tested for the presence of E. coli O157:H7 using immunomagnetic bead separation and selective culture. There was a strong statistical association between sampling date and the likelihood of a fecal sample testing positive for E. coli O157:H7. Pen was also a strong predictor of fecal prevalence. Despite accounting for this high level of clustering, a statistically significant association between reduced water levels in the trough and increased prevalence of E. coli O157:H7 in the feces was observed (Odds Ratio = 1.6; 95% Confidence Interval: 1.2–2.0; Likelihood Ratio Test: p = 0.02). This is the first time that such an association has been reported, and suggests that increasing water-trough levels may be effective in reducing shedding of E. coli O157:H7 in cattle feces, although further work would be needed to test this hypothesis. Controlling E. coli O157:H7 fecal shedding at the pre-harvest level may lead to a reduced burden of human foodborne illness attributed to this pathogen in beef.
Highlights
Escherichia coli O157:H7 is the predominant serotype representing the Shiga-toxin producing E. coli group associated with human disease
There was no statistical association between whether E. coli O157:H7 was identified in a pen and either mean weight of animals, number of animals in the pen, or days in feeding (p>0.5; Mann-Whitney U test for continuous variables)
Diagnostic plots provided no evidence suggesting a non-linear relationship. This intervention trial provided evidence that decreasing the level of water in troughs in feedlot pens that are already contaminated with E. coli O157:H7 may modestly increase the Escherichia coli O157:H7 in cattle fecal pats and water trough levels on feedlots proportion of fecal pats that are positive for E. coli O157:H7
Summary
Escherichia coli O157:H7 is the predominant serotype representing the Shiga-toxin producing E. coli group associated with human disease. It was first identified as a pathogen in 1982 during an outbreak investigation of hemorrhagic colitis [1]. The total annual economic burden of illness due to E. coli O157:H7 resulting from medical expenses and loss of life and productivity is estimated to be $405 million [6]. The beef industry suffers economic losses directly from recalls of E. coli O157:H7-contaminated raw non-intact beef (and its components) and indirectly from subsequent decline in consumer demand for beef in the market. It has been reported that beef recalls by the Food Safety Inspection Services caused a decline in beef demand [8]. Consumer buying practices are greatly influenced by perception of the food safety of any given product [9, 10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
