The Influence and Therapeutic Use of Bacteriophage against Campylobacters Entering the Human Food Chain

The food-borne pathogens Campylobacter jejuni and Campylobacter coli are a major concern in the UK with estimates of more than 80 per cent of chickens harbouring these organisms. The aim of this project is to examine the population dynamics of naturally occurring bacteriophage and how these influence the numbers and strains/species of campylobacters colonising chickens and ultimately entering the human food chain. <P>
The research will provide a theoretical basis for use in phage intervention strategies both in campylobacter and in general. Further it will also assist our understanding of the limited strain types prevalent in human campylobacteriosis cases. <P> Previous work has shown that bacteriophage can be used to reduce campylobacters in the caeca of experimentally infected birds. In addition naturally phage-infected poultry have reduced Campylobacter numbers in their caeca compared to birds from which phage cannot be recovered. Since previous general mathematical predictions of phage activity have been shown not to be applicable to these experimental birds we propose to construct a kinetic model for campylobacter bacteriophage in vivo. This could provide a generalised basis to understand phage therapy targeted at a commensal organism rather than an overt pathogen and a rational basis for bacteriophage intervention aimed to reduce the numbers of campylobacters entering the human food chain. <P> In addition studies will be carried out in order to understand the epidemiology of phage with respect to observed molecular changes in the host and correlate these genotypes with broiler chicken isolates. We will investigate the mechanism of phage sensitivity/resistance associated with a specific chromosomal rearrangement in broiler chicken Campylobacter isolates that is independent of phage genetic material and governs their colonisation potential. <P>An investigation of the genotypes of strains isolated from patients with campylobacter enteritis will be carried out to determine if these changes are related to those associated with phage programmed changes. Bacteriophage intervention would constitute a minimally invasive natural procedure that could be applied to both intensively reared and organic/free range birds alike. <P> The data generated will be of use in risk models for human infection and that will be made available for that. (Joint with BB/C504543/1)