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Title: PATHOGENESIS OF O157:H7 ESCHERICHIA COLI IN NEONATAL CALVES

Author
item Nystrom, Evelyn
item Bosworth, Brad
item Moon, Harley

Submitted to: Rushmore Conference on Mechanisms in Pathogenesis of Enteric Diseases
Publication Type: Abstract Only
Publication Acceptance Date: 9/28/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Cattle have been implicated as an important reservoir of Shiga-like toxin-producing Escherichia coli (SLTEC) O157:H7 that cause hemorrhagic colitis and hemorrhagic uremic syndrome in humans. Naturally- or experimentally-infected cattle can shed low levels of E. coli O157:H7 long-term, but little is known about the pathogenesis of E. coli O157:H7 infection in cattle. E. coli O157:H7 induce characteristic attaching and effacing (AE) mucosal lesions in ceca and colons of 1-day-old gnotobiotic piglets and this model is used to study the pathogenesis of SLTEC infections. AE lesions have not been detected in adult cattle or 3- to 14-wk-old calves infected with E. coli O157:H7. Our objective was to determine if E. coli O157:H7 induce AE lesions in neonatal calves. Colostrum-deprived calves (less than 12-hr-old) were bottle-fed with antibiotic-free milk replacer containing 10**10 CFU of O157:H7 (SLT-I+, SLT-II+) or nonpathogenic E. coli, necropsied 18 h postinfection and examined histologically. Bacterial attachment, effacement of microvillous borders and destruction of mucosal epithelium were observed in the intestines of calves inoculated with E. coli O157:H7. No lesions were observed in calves inoculated with nonpathogenic E. coli. The distribution of intestinal lesions in these calves resembled that in gnotobiotic pigs. Neonatal calves are apparently more susceptible to AE lesions induced by E. coli O157:H7 than are older calves or adult cattle and provide a model for studying the pathogenesis of E. coli O157:H7 infections in cattle.