Review of the Food-borne Zoonoses Research ... - ARCHIVE: Defra

Although enhanced biosecurity measures on farms appear to reduce colonisation of
flocks, the proportion of Campylobacter positive flocks entering the processing plant
remains high. Therefore it is necessary to identify strategies for on-farm interventions in
order to reduce the total campylobacter load on farms and their ability to persist in the
bird until slaughter. To achieve this the reservoirs of campylobacters surviving or
recycling within or re-entering the farm are being investigated. The impact of both abiotic
and biotic environmental factors e.g bacteriophage, on campylobacter persistence in the
environment and their influence on colonisation and seasonality of campylobacter
carriage in broiler flocks is being studied to improve the understanding of the survival
mechanisms. In addition the ability to detect, identify and classify campylobacter strains
in poultry farm environments is being advanced. Scientists from a range of disciplines
including microbiology, with expertise in aerobiology, bacteriophage and biofilms in the
poultry environment, and poultry epidemiologists, specialising in veterinary, molecular
characterisation, modelling, and risk analysis are involved in this project. This team is
being aided by advice and collaboration with consultants of international standing from
Denmark, Sweden, Netherlands, USA and the UK. In-vivo chick modelling is being used
to investigate the susceptibility of broilers to colonisation by campylobacters in
environmental samples identified as potential reservoirs of infection. The studies are
benefiting from the probe approach developed for project OZ0608 to identify sources
associated with caecal campylobacter strains colonising the broiler flocks. Links
identified by SVR sequence are being explored further using MLST. On-going research
projects at both participating institutes are informing this project while close collaboration
with the poultry industry is ensuring rapid communication of research outputs and that
strategies recommended will be adopted.
OZ0613
The work undertaken by project OZ0613 is a comprehensive package of multidisciplinary
research aimed at supplying data on which to base practical policy decisions
on the control of Campylobacter in broiler production.
The laboratory and in-field validation work carried out in Objective 1 will provide
sensitivity and specificity data on the Campylobacter Survey methodology (Objective 2).
By determining these data suitable correction factors can be applied to the apparent
survey prevalence, via a modelling approach, to obtain an estimate of the true
prevalence.
The survey carried out in Objective 2 is the first survey on Campylobacter in broiler flocks
at slaughter to be carried out in the UK on a national-scale. The survey has been based
on the EU specifications and as such will meet the main requirements of the EU survey
when it becomes mandatory (which is likely to be January 2008). By commencing the
survey in January 2007 the VLA has been able to trial the EU methodology and identify a
number of issues which have been fed back to Defra. In addition to determining the
prevalence of Campylobacter in broiler flocks at slaughter, the research undertaken by
the VLA will provide a valuable data set for investigating risk factors associated with flock
prevalence. The survey also provides a valuable, epidemiologically robust, source of
samples which can be used for molecular epidemiological studies, particularly
comparison with human strains by MLST or other suitable methods, and for antimicrobial
resistance testing.
Objective 3 focuses on more detailed epidemiological investigations of the depopulation
process. This work is linked with an existing University of Bristol FSA project and will
provide substantial added value by virtue of provision of strains from Bristol studies of the
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