Lammers G A C, McCONNEL C S, Jordan D, Ayton M S, Morris S, Patterson E I, Ward M P, Heller J
School of Animal and Veterinary Science,Charles Sturt University,Australia.
Department of Clinical Sciences,Colorado State University,USA.
Epidemiol Infect. 2015 Nov;143(15):3244-55. doi: 10.1017/S0950268815000588. Epub 2015 Mar 31.
This study aims to describe in detail the temporal dynamics of E. coli O157 shedding and risk factors for shedding in a grass-fed beef herd. During a 9-month period, 23 beef cows were sampled twice a week (58 sampling points) and E. coli O157 was enumerated from faecal samples. Isolates were screened by PCR for presence of rfbE, stx 1 and stx 2 . The prevalence per sampling day ranged from 0% to 57%. This study demonstrates that many members of the herd were concurrently shedding E. coli O157. Occurrence of rainfall (P < 0·01), feeding silage (P < 0·01) and lactating (P < 0·01) were found to be predictors of shedding. Moving cattle to a new paddock had a negative effect on shedding. This approach, based on short-interval sampling, confirms the known variability of shedding within a herd and highlights that high shedding events are rare.
本研究旨在详细描述草饲牛群中大肠杆菌O157排泄的时间动态以及排泄的风险因素。在9个月的时间里，每周对23头肉牛进行两次采样（共58个采样点），并对粪便样本中的大肠杆菌O157进行计数。通过聚合酶链反应（PCR）筛选分离株中rfbE、stx 1和stx 2的存在情况。每个采样日的患病率在0%至57%之间。本研究表明，牛群中的许多成员同时排泄大肠杆菌O157。发现降雨（P < 0·01）、饲喂青贮饲料（P < 0·01）和泌乳（P < 0·01）是排泄的预测因素。将牛转移到新的围场对排泄有负面影响。这种基于短间隔采样的方法证实了牛群中已知的排泄变异性，并突出表明高排泄事件很少见。
