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

Project code: OZ0712
Project title: Escherichia coli O157 interventions and control
Start date (dd/mm/yy): 01/04/2003
End date (dd/mm/yy): 30/09/2006
£503,523
Total cost:
Affiliation: SAC
Sub-contractor(s): University of Edinburgh
Abstract of research
BioSS
Verocytotoxin producing Escherichia coli (VTEC) serotype O157:H7 is a significant
infectious intestinal disease pathogen that can cause a severe and potentially fatal illness
in humans. The main reservoir of E. coli O157 is the gastrointestinal tract of cattle, and
the overall size of this animal reservoir is a major determinant of the threat that the
organism poses to public health.
Our group have made significant advances in understanding the persistence of the
organism in the bovine host and identified the terminal rectum as the primary site for
colonisation associated with persistent and high level excretion of the organism. The
primary objective of study OZ0712 is to understand this colonisation of the terminal
rectum and to examine treatments or interventions to reduce or prevent carriage at the
site. Practical control strategies may be developed from the understanding of the
bacterial-host interactions that allow E. coli O157:H7 to persist on the rectal mucosa or
from the development of methods that treat or prevent colonisation. Opportunity will also
be taken to validate simple screening tests that could be used in the field or abattoir to
identify colonised animals.
Review summary
This project aimed to acquire knowledge of how E. coli O157:H7 persists in the GI tract
of cattle, and to use this information to develop practical methods for detection and
control.
The research team have significantly contributed to our understanding of the persistence
of E. coli O157:H7 in the bovine host, and in identifying the terminal rectum as the
primary site for colonisation. A simple dip stick method was also developed for detection
of high level faecal carriage of this organism. Direct application of chlorhexidine to the
terminal rectal mucosa was found to be the most effective treatment investigated. This
treatment was able to reduce or completely eliminate E. coli O157:H7 and has the
potential to be an important control option. The development of this practical intervention
is being taken forward in project OZ0714 (To develop a cost effective and practical
method to reduce E. coli O157 infection in cattle prior to slaughter).
94