Experimental Escherichia coli O157:H7 carriage in calves
Experimental Escherichia coli O157:H7 carriage in calves
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DOI：
10.1128/aem.63.1.27-32.1997
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发表时间：
1997-01-01
影响因子：
4.4
通讯作者：
Doyle, MP
中科院分区：
文献类型：
--
作者：
Brown, CA;Harmon, BG;Doyle, MP
9头断奶小牛（6 - 8周龄）经口胃插管给予10（10）CFU的肠出血性大肠杆菌O 157：H7的5种菌株混合物。在3头小牛出现最初的短暂发热和5头小牛出现短暂的轻度腹泻后，小牛在整个13- 27天的研究期间临床正常。在接种后的前2周内，所有犊牛粪便中的大肠杆菌O 157：H7均显著下降，此后，出现了小种群脱落。大肠杆菌O 157：H7在犊牛体内持续存在，在犊牛粪便和瘤胃内容物中间歇性检出。大肠杆菌O 157：H7感染率为1 ~ 2 log（10）/g。coliO 157：H7，禁食对大肠埃希菌粪便排泄的影响。大肠杆菌O 157：H7在排出较大群体的小牛中是可变的，在尸检时，未从消化道外的部位分离出大肠杆菌O 157：H7。E.大肠杆菌O 157：H7在所有犊牛的前胃或结肠中均分离到，大肠杆菌O 157：H7在胃肠道内容物中的表达高于相应的粘膜切片，且无组织学或免疫组化证据。coli O 157：H7粘附于粘膜。大肠杆菌O 157：H7在断奶小牛中不致病，虽然它似乎不会在粘膜表面长时间定殖，但大肠杆菌O 157：H7作为粪便脱落的来源存在于瘤胃和结肠的内容物中。
Nine weaned calves (6 to 8 weeks of age) were given 10(10) CFU of a five-strain mixture of enterohemorrhagic Escherichia coli O157:H7 by oral-gastric intubation, After an initial brief period of pyrexia in three calves and transient mild diarrhea in five calves, calves were clinically normal throughout the 13- to 27-day study, The population of E. coli O157:H7 in the feces decreased dramatically in all calves during the first 2 weeks after inoculation, Thereafter, small populations off. coli O157:H7 persisted in all calves, where they were detected intermittently in the feces and rumen contents, While withholding food increased fecal shedding of E. coli O157:H7 by 1 to 2 log(10)/g in three of four calves previously shedding small populations of E. coli O157:H7, the effect of fasting on fecal shedding of E. coli O157:H7 was variable in calves shedding larger populations, At necropsy, E, coli O157:H7 was not isolated from sites outside the alimentary tract. E. coli O157:H7 was isolated from the forestomach or colon of all calves at necropsy, Greater numbers of E. coli O157:H7 were present in the gastrointestinal contents than in the corresponding mucosal sections, and there was no histologic or immunohistochemical evidence off. coli O157:H7 adhering to the mucosa, In conclusion, under these experimental conditions, E. coli O157:H7 is not pathogenic in weaned calves, and while it does ndt appear to colonize mucosal surfaces for extended periods, E coli O157:H7 persists in the contents of the rumen and colon as a source for fecal shedding.