A current study funded by an FDA grant traces the path of E. coli O157 and Salmonella on farms.
Fecal, feed and water samples will be taken from 24 dairies over a 2-year period. These samples will be cultured for both E. coli O157 and Salmonella species. The prevalence of pathogens in the feed and water will be compared to the prevalence of pathogens in the cattle feces to help answer questions about how cattle are exposed to infection.
The study encompasses the following goals:
- Determine if total dietary E. coli exposures are correlated with the prevalence of E. coli O157 and Salmonella sp. infection in exposed cattle.
- Determine the frequency of contamination of cattle foodstuffs and water sources with E. coli O157 and Salmonellasp..
- Determine the ability of cattle feeds and water sources to support the replication of the enteropathogenic bacteria E. coli O157 and Salmonella sp..
- Determine whether feed and water contamination frequency and the ability of feed and water sources to support the proliferation of E. coli O157 or Salmonella sp. are significantly associated with the prevalence of bovine infection with E. coli O157 or& Salmonella sp. in the herds consuming that feed and water.
Results as of June 30, 1999 (Preliminary):
- Total E. coli exposures in feed and water seem stable over time.
- E. coli O157 and Salmonella have been found in bunk feeds, water troughs, and component (purchased) feeds.
- We have successfully completed growth assays for generic E. coli and Salmonella typhimurium DT104 in total mixed rations from all farms, and none were found to support growth of these organisms.
- There seems to be a relatively high degree of natural variability among the herds in terms of bacterial counts and prevalences of E. coli O157 and Salmonella.