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Measures to significantly reduce the level of E. coli O157:H7 carriage in cattle will ensure microbiologically safer food. We will use several live, attenuated vaccine strains of Salmonella expressing important surface proteins of E. coli 0157:H7 to vaccinated calves. Vaccination of calves with Salmonella strains expressing surface proteins of E.coli O157:H7 will engender a mucosal immune response. By stimulating mucosal immunity, it is hoped that the E.coli 0157:H7 will not have an opportunity to colonize the lower bowel of the calves.
Escherichia coli 0157:H7 is an emerging zoonotic bacterial pathogen. This strain of E. coli causes enteric disease inhumans ranging from self-limiting,non-bloody diarrhea to severe hemorrhagic colitis. E. coli 0157:H7 can also cause devastating extraintestinal illness, most importantly hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP).E.coli O157:H7 remains by the far the most clinically important enterohemorrhagic E. coli (EHEC) serovar at the present time. E. coli O157:H7 is a food-bome pathogen. Beef and dairy cattle are thought to be the most importantanimal reservoir. The most extensive outbreaks of E. coli O157:H7 infection have involved ground beef where the destructionof large quantities of contaminated beef products was required. E. coli O 157 :H7 has become a significant human pathogen and has had a major economic impact on the beef industry.
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Calves will then be challenged with virulent E.coli 0157:H7 and the severity of diarrhea measured. The reduction or elimination ofE.coli O157:H7 from these vaccinated animals well be determined. Means to significantly reduce or eliminate E.coliO157:H7 from cattle will ensure a safer food supply.