Submitted to: International Symposium and Workshop on Shiga Toxin ... Escherichia coli
Publication Type: Abstract Only
Publication Acceptance Date: 11/2/2000
Publication Date: N/A
Technical Abstract: Cattle are important reservoirs of enterohemorrhagic Escherichia coli (EHEC) O157:H7 that cause disease in humans. Both dairy and beef cattle are asymptomatically and sporadically infected with EHEC. Our long-term goal is to develop an effective vaccine to prevent cattle from becoming infected and transmitting EHEC O157:H7 to humans. We are using passive immunization of neonatal piglets (as a surrogate model) to determine if maternal antibodies against an EHEC O157 adhesin (intiminO157) inhibit EHEC colonization. Pregnant gilts with anti-intimin titers < 100 were vaccinated twice with purified intiminO157 before farrowing. Colostral anti-intimin titers of vaccinated and non-vaccinated sows were >/= 10,000 and < 100, respectively. Neonatal piglets were allowed to suckle up to 8 h before they were inoculated with 10**6 CFU of a Shiga toxin-negative (for humane reasons) strain of EHEC O157:H7. All pigs remained clinically healthy. At necropsy (3 or 4 d pi), intestinal samples were collected for histology and bacteriological counts. All 6 piglets nursing the non-vaccinated sow had attaching and effacing (A/E) O157**+ bacteria in the large intestine and >/= 10**6 CFU of inoculum bacteria/g of cecal tissue. In contrast, only 1 of 5 piglets suckling the vaccinated sow had A/E bacteria (few A/E bacteria in the cecum that were detected only by immunohistochemical staining) and all had < 10**4 CFU/g. We conclude that intiminO157 may be a good candidate for an EHEC O157:H7 anti-transmission vaccine.