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Prevalence and Growth of E. coli O157:H7 in the Bovine Gall Bladder


The objectives of this study were to determine the prevalence of E. coli O157:H7 in gall bladders
from naturally-infected animals and to evaluate the growth and survival of E. coli in bovine bile.

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Findings: The results from this study show that serotype O157:H7 strains can grow in bile from cattle and
that 3% of gall bladders tested harbored this pathogen. However, a prevalence of approximately
3% does not indicate that the gall bladders of all cattle harboring this pathogen are colonized.
<P> The growth of the E. coli O157:H7 strains in 16% bile salts were unexpected and contribute to the
ability of this pathogen to compete in the intestinal tract and persist in the environment and
throughout the food production chain. The results from this study clearly demonstrate that this
pathogen is bile tolerant and can reside and replicate in the gall bladder of infected cattle. What
remains unanswered is whether this site is persistently colonized or it transiently occupied. The
bile tolerance noted in this study certainly provides a competitive advantage to the organism once
it gains access to the bile duct and gall bladder.

Kaspar, Charles
University of Wisconsin - Madison
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