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Vaccination as an Intervention Strategy for the Reduction of Escherichia coli O157:H7


Significant progress has been made in reducing the incidence of E. coli O157:H7 in the harvest
sector. The development of multiple hurdle intervention systems and the implementation of
Hazard Analysis Critical Control Points (HACCP) based inspection systems have all contributed
to the reduction of this deadly pathogen. While that progress is encouraging, concerns have
arisen that with the highly prevalent nature of E. coli O157:H7 in the production sector,
measures should be investigated that attempt to prevent or minimize the risk that slaughter cattle
would carry foodborne pathogens into harvest facilities. As a result, researchers are focusing
efforts on intervention methods that can be applied to live animals to reduce or potentially
eliminate E. coli O157:H7 prior to cattle ever entering a slaughter facility. <P>
The objectives of this project were twofold: <br/>
1. Determine the baseline prevalence for the proportion of freshly weaned calves shedding
Escherichia coli O157:H7; and
2. Determine the effectiveness of an experimental vaccine as a pre-harvest intervention
strategy for reducing the proportion of calves shedding E. coli O157:H7 in the feces.

More information

Findings: The low prevalence of E. coli observed in this experiment limits the analysis and makes it
difficult to assess the effectiveness of the Escherichia coli vaccine. The researchers suggested
that future comparisons be conducted using animals inoculated with E. coli O157:H7 to prevent
the difficulties associated with low prevalence. The researchers did feel however, that the
baseline prevalence of 9.4 percent among the weaned calves was enough to perpetuate infection
and should be considered a problem worth addressing with intervention methods.

<P> For complete projects details, view the <a href="…; target="_blank">Project Summary. </a>

Paterson, John; Smith, Gary; Belk, Keith
Colorado State University
Montana State University
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