Affiliation:
1. Veterinary Medical Research Institute, Iowa State University,1 and
2. Enteric Diseases and Food Safety Research Unit, National Animal Disease Center, UDSA Agricultural Research Service,2 Ames, Iowa 50011
Abstract
ABSTRACT
Shiga toxin-producing
Escherichia coli
(STEC) is an important cause of food-borne illness in humans. Ruminants appear to be more frequently colonized by STEC than are other animals, but the reason(s) for this is unknown. We compared the frequency, magnitude, duration, and transmissibility of colonization of sheep by
E. coli
O157:H7 to that by other pathotypes of
E. coli
. Young adult sheep were simultaneously inoculated with a cocktail consisting of two strains of
E. coli
O157:H7, two strains of enterotoxigenic
E. coli
(ETEC), and one strain of enteropathogenic
E. coli
. Both STEC strains and ETEC 2041 were given at either 10
7
or 10
10
CFU/strain/animal. The other strains were given only at 10
10
CFU/strain. We found no consistent differences among pathotypes in the frequency, magnitude, and transmissibility of colonization. However, the STEC strains tended to persist to 2 weeks and 2 months postinoculation more frequently than did the other pathotypes. The tendency for persistence of the STEC strains was apparent following an inoculation dose of either 10
7
or 10
10
CFU. One of the ETEC strains also persisted when inoculated at 10
10
CFU. However, in contrast to the STEC strains, it did not persist when inoculated at 10
7
CFU. These results support the hypothesis that STEC is better adapted to persist in the alimentary tracts of sheep than are other pathotypes of
E. coli
.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
68 articles.
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