Escherichia Coli O157 Interventions and Control

The primary objective of the study is to understand colonisation of the terminal rectum and to examine treatments or interventions to reduce or prevent carriage at the site. Practical control strategies could be developed from the understanding of the interactions that allow E. coli O157 to persist on the rectal mucosa or from methods that treat or prevent colonisation. Opportunity will be taken to validate simple screening tests that could be used in the field or abattoir to identify persistent excretors.
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The first objective is to establish the best method for reproducible colonisation of the terminal rectum and to examine if persistent colonisation can be established by direct application of the organism to the site or is dependent upon colonisation of more proximal GIT sites.
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The second major objective for the proposal will be to utilise those animals that are colonised at the terminal rectum and to examine different interventions that eliminate carriage.
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The third objective is to develop a simple screening test that can be applied in the field for the detection of target organism carriage at the recto-anal site of colonisation.
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The specific experimental objectives proposed are:
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To examine the efficiency of oral, rectal and intraruminal challenge routes in establishing rectal colonisation, and to examine other possible sites of adherence within the bovine gastrointestinal tract,
<LI> To investigate specific treatment interventions for control of faecal excretion,
<LI> To develop simple tests to identify the persistent carrier status and to understand the dynamics of persistence at the major site.