Comparative Pathogenicity of Wildlife and Bovine Escherichia coli O157:H7 Strains in Experimentally Inoculated Neonatal Jersey Calves.

ABSTRACT

Shiga toxin-producing Escherichia coli, like E. coli O157H7, are important human and animal pathogens. Naturally-acquired E. coli O157H7 infections occur in numerous species but, particularly, cattle have been identified as a significant reservoir for human cases. E. coli O157H7 are isolated from a number of domestic and wild animals, including rodents that share a living space with cattle. These Shiga toxin-producing E. coli O157H7 strains can be highly virulent in humans, but little is known about the sequelae of interspecies transfer. In a group of neonatal calves, we determined the differences in colonization patterns and lesions associated with infection using either a wildlife or bovine E. coli O157H7 strain. In calves challenged with the wildlife E. coli O157H7 strain, the large (descending) colon was solely colonized, which differed substantially from the calves inoculated with the bovine E. coli O157H7 strain, where the spiral colon was the principal target of infection. This study also demonstrated that while both interspecies- and intraspecies-derived E. coli O157H7 can infect young calves, the distribution and severity differs.