Siderophore Receptor and Porin-Based Vaccine For Pre-Harvest Control of Escherichia coli 0157:H7 in Feedlot Cattle

Abstract

Escherichia coli O157:H7, which is harbored in the intestines of cattle, is a major food borne pathogen that causes hemorrhagic enteritis and hemolytic uremic syndrome in humans. Recent data indicate that pre-harvest prevalence in groups of cattle is associated with the subsequent post-harvest contamination of carcasses. Because of this, efforts to reduce carriage of this organism in harvest-ready cattle will likely reduce the number of carcasses that are contaminated with E. coli O157:H7. A novel vaccine that contains siderophore receptors and porin proteins (SRP) was designed to block the passage of iron into the bacterial cell, essentially eliminating its nutrients and reducing further colonization of this pathogenic microorganism. Previous studies have shown that this vaccine significantly reduced fecal shedding and promoted an immune response in 4 month-old mixed breed calves that were orally inoculated with naladixic acid resistant strains of E. coli O157:H7. Further evaluation of the efficacy of this vaccine in feedlot cattle is necessary. Therefore, the purpose of this study was to examine the efficacy of the SRP vaccine on the prevalence and shedding of E. coli O157:H7 in feedlot cattle.