Stoffregen William C, Pohlenz Joachim F L, Dean-Nystrom Evelyn A
Pre-Harvest Food Safety Research Unit, National Animal Disease Center, US Department of Agriculture, Agricultural Research Service, PO Box 70, Ames, IA 50010, USA.
J Vet Diagn Invest. 2004 Jan;16(1):79-83. doi: 10.1177/104063870401600114.
Fifteen weaned calves (age 89-141 days) were treated with dexamethasone (0.25 mg/kg, IV) for 3 days before, the day of, and the day after inoculation with 10 colony-forming units of either Escherichia coli O157:H7 (strain 86-24, which produces Shiga toxin 2 and intimin; n = 13) or nonpathogenic E. coli (strain 123, which does not produce Shiga toxin or intimin; n = 2). All calves were necropsied 4 days after inoculation. Histologic lesions of attaching and effacing bacteria were observed in the large intestine (12/13) and in the gallbladder mucosa (5/13) of calves inoculated with E. coli 86-24. Cholecystitis was present in 12 of 13 calves that received E. coli 86-24. Inoculum bacteria were recovered from the distal colons or feces (13/13) and gallbladders (3/4) of calves inoculated with 86-24.
15头断奶犊牛（年龄89 - 141天）在接种10个菌落形成单位的大肠杆菌O157:H7（86 - 24株，产生志贺毒素2和紧密黏附素；n = 13）或非致病性大肠杆菌（123株，不产生志贺毒素或紧密黏附素；n = 2）之前3天、接种当天及接种后一天，静脉注射地塞米松（0.25 mg/kg），共3天。所有犊牛在接种后4天进行剖检。接种86 - 24株大肠杆菌的犊牛，在大肠（12/13）和胆囊黏膜（5/13）观察到紧密黏附细菌的组织学损伤。13头接种86 - 24株大肠杆菌的犊牛中有12头出现胆囊炎。接种86 - 24株大肠杆菌的犊牛，在远端结肠或粪便（13/13）以及胆囊（3/4）中分离到接种菌。
