Author
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NYSTROM, EVELYN |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 9/4/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Cattle are an important reservoir of Shiga-like toxin-producing Escherichia coli O157:H7 that cause hemorrhagic colitis and hemolytic uremic syndrome in humans. Naturally- or experimentally-infected cattle can shed low levels of E. coli O157:H7 for a long period, but little is known about the pathogenesis of E. coli O157:H7 infection in cattle. E. coli O157:H7 induced characteristic attaching and effacing (AE) mucosal lesions in ceca and colons of 1-day-old gnotobiotic piglets. AE lesions have not been detected in adult cattle or 3- to 14-week-old calves infected with E. coli O157:H7. The objective was to determine if E. coli O157:H7 induce AE lesions in neonatal calves. Colostrum-deprived calves (less than 12-h-old) were bottle-fed with antibiotic-free milk replacer containing either 10**10 CFU of O157:H7 (SLT-I+, SLT-II+) or nonpathogenic E. coli, necropsied 18-h or 3-d postinoculation and examined histologically. Calves inoculated with E. coli O157:H7 had diarrhea, colonic edema and A/E lesions in both the large and small intestines 18 h and 3 d postinoculation. No diarrhea, edema or A/E lesions were observed in calves inoculated with nonpathogenic E. coli. Colostrum-fed calves (30- to 36-h-old) also had diarrhea, edema and AE lesions after inoculation with E. coli O157:H7. Neonatal calves are susceptible to AE lesions induced by E. coli O157:H7 and provide a model for studying the pathogenesis of E. coli O157:H7 infections in cattle. |
