Influence of toxic enophyte-infected tall fescue on the prevalence of E. coli 0157:H7 from ruminants, a review

Abstract

Ruminants consuming toxic endophyte-infected (E+) tall fescue are exposed to ergot alkaloids that usually result in a malady of problems identified as fescue toxicosis. Grazing studies investigating the effects of E+ tall fescue on the prevalence of E. coli O157:H7 from naturally-infected cattle have not been consistent. Further, in vitro studies with selected ergot alkaloids did not affect growth of E. coli O157:H7. Dietary stressors usually associated with E+ tall fescue consumption did result in increased faecal shedding of E. coli O157:H7 from sheep experimentally-inoculated. Animal species, animal model (naturally vs experimentally-infected), environmental conditions, type of diet, and length of exposure to E+ tall fescue may influence the association between grazing E+ tall fescue and E. coli O157:H7 shedding. A better understanding of how E+ tall fescue influences shedding of E. coli O157:H7 from ruminants will aid in the development of management strategies for onfarm pathogen control. Keywords: cattle, E. coli O157:H7, sheep, tall fescue