The potential risk associated with foodborne pathogens in a watershed: Escherichia coli O157:H7 in dairy cattle

We carried out an investigation to determine the occurrence of Escherichia coli O157:H7 in dairy herds in the Delaware County watershed and to identify the factors that play a role in the likelihood of presence of this organism among animals on these farms. The pathogen poses risk of environmental degradation and health to the inhabitants. A total of 2162 fecal samples were collected per rectum from a representative sample of cattle on 27 dairy farms. The samples were investigated for the presence of E. coli O157:H by initially enriching using a bacteriological media and detection of the pathogen using real-time polymerase chain reaction technique. Escherichia coli O157:H7 was detected in 74% of the herds in the target population and in 3.7% of samples collected. An additional 54 animals were identified that were infected with O157 non-H7 strains of E. coli among 15 farms. Several putative risk factors were associated with the detection of the pathogen on the enrolled farms included age, housing calves indoors, group housing for calves, housing calves in the calf barn, presence of dogs on the farm, and housing post-weaned calves in a cow barn or heifer barn versus a greenhouse. In conclusion, E. coli O157:H7 was present on the dairy farms of Delaware County and may pose a threat to the people that live and work there. The risk associated with the detection of this pathogen could be reduced by adjusting management factors that were identified in this study.