Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: May 23, 1996
Publication Date: N/A
Cattle are an important reservoir of enterohemorrhagic Escherichia coli O157:H7 that cause hemorrhagic colitis and hemorrhagic uremic syndrome in humans. Naturally- or experimentally-infected cattle can shed E. coli O157:H7 long term, but little is known about the pathogenesis of E. coli O157:H7 infections in cattle. No overt clinical signs and no adherent bacteria or intestinal lesions have been detected in adult cattle or more than 3-wk-old calves experimentally infected with E. coli O157:H7. However, E. coli O157:H7 induce attaching and effacing (AE) mucosal lesions in ceca and colons of 1-day-old gnotobiotic piglets. Our objective was to determine if E. coli O157:H7 produce AE lesions in neonatal calves and piglets. Colostrum-deprived calves (less than 12-h-old) and colostrum-deprived piglets (less than 8-h-old) were inoculated with 10**10 CFU of E. coli O157:H7 or nonpathogenic E. coli, necropsied 18 h postinfection, and examined histologically. Bacterial attachment and AE lesions were observed in the intestines of calves and piglets inoculated with E. coli O157:H7 but not in animals inoculated with nonpathogenic E. coli. Intestinal lesions were similarly distributed in neonatal calves and piglets. Both neonatal calves and neonatal piglets are susceptible to AE lesions induced by E. coli O157:H7 and both models will be useful for studying mechanisms of E. coli O157:H7 infections in cattle.