Oral and Poster Abstracts

Conclusion: The total contamination rate of salmonellae is variable
during seasonal changes. The grinded meats (8.6%) were more
contaminated as compared with absolute meats (6.2%). The S.
typhimurium was the most contaminator serotype of salmonellae in
ovine meatsThe presence of S. paratyphi B serotype in grinded meats
might be explained by spread of contaminations from human
vectors.
Key words: meat hygiene, microbiology, salmonella bacteria
321 Vaccination of Cattle with E. coli O157:H7 Type III Secretion
Proteins as a Pre-slaughter Intervention Method to Reduce E.
coli O157:H7 Prevalence
D. Rogan 1 , D. Smith 2 , R. Moxley 2 , A. Potter 3 , J. Yome 1
1
Bioniche Animal Health Canada, Research & Development,
Belleville, Ontario, Canada, Canada
2
University of Nebraska-Lincoln, Research & Development, Lincoln,
Nebraska, United States
3
Vaccine & Infectious Disease Organization, Director and CEO,
Saskatoon, SK, Canada
Enterohaemorrhagic Escherichia coli O157:H7 (EHEC) is an
important pathogen of humans, causing severe diarrhea and
hemolytic uremic syndrome (HUS). In North America, EHEC
serotype O157:H7 is most prevalent, causing 85-95% of HUS cases.
Cattle are an important resevoir of E. coli O157:H7 and as such, are
a major source of infection in humans, through direct contact or the
consumption of contaminated meat, water, or produce. E. coli
O157:H7 infection of cattle requires type III secreted proteins
(TTSP) which enable the bacteria to colonize the intestinal mucosa.
Bioniche Animal Health has developed an E. coli O157:H7 TTSP
vaccine that contains the TTSP proteins EspA, EspB and Tir. The
efficacy of this vaccine has been evaluated in cattle using natural
exposure and controlled challenge studies. To assess the effects of
vaccination on the shedding of E. coli O157:H7, calves were
vaccinated with three doses and challenged with E. coli O157:H7 14
days later. There was a 2.28 log 10 reduction in the magnitude of
shedding in vaccinated animals compared to controls. In another
study, with a three dose vaccination and natural exposure to E. coli
O157:H7, vaccinated animals were less likely to be colonized by the
bacteria in the mucosa of the terminal rectum at harvest (OR=0.014,
p