McGee P, Scott L, Sheridan J J, Earley B, Leonard N
Teagasc, The National Food Centre, Ashtown, Dublin, Ireland.
J Food Prot. 2004 Dec;67(12):2651-6. doi: 10.4315/0362-028x-67.12.2651.
Ruminant livestock, particularly cattle, is considered the primary reservoir of Escherichia coli O157:H7. This study examines the transmission of E. coli O157:H7 within groups of cattle during winter housing. Holstein Friesian steers were grouped in six pens of five animals. An animal inoculated with and proven to be shedding a marked strain of E. coli O157: H7 was introduced into each pen. Fecal (rectal swabs) and hide samples (900 cm2 from the right rump) were taken from the 36 animals throughout the study. Water, feed, and gate or partition samples from each pen were also examined. Within 24 h of introducing the inoculated animals into the pens, samples collected from the drinking water, pen barriers, and animal hides were positive for the pathogen. Within 48 h, the hides of 20 (66%) of 30 cohort animals from the six pens were contaminated with E. coli O157:H7. The first positive fecal samples from the noninoculated cohort animals were detected 3 days after the introduction of the inoculated steers. During the 23 days of the study, 15 of 30 cohort animals shed the marked E. coli O157:H7 strain in their feces on at least one occasion. Animal behavior in the pens was monitored during a 12-h period using closed circuit television cameras. The camera footage showed an average of 13 instances of animal grooming in each pen per hour. The study suggests that transmission of E. coli O157:H7 between animals may occur following ingestion of the pathogen at low levels and that animal hide may be an important source of transmission.
反刍家畜，尤其是牛，被认为是大肠杆菌O157:H7的主要宿主。本研究调查了冬季圈养期间牛群中大肠杆菌O157:H7的传播情况。将荷斯坦弗里生公牛犊分成六组，每组五头。将一头接种并经证实正在排出显著菌株的大肠杆菌O157:H7的牛引入每组。在整个研究过程中，从36头牛身上采集粪便（直肠拭子）和皮肤样本（右臀部900平方厘米）。还对每组的水、饲料以及门或隔板样本进行了检测。在将接种动物引入牛栏后的24小时内，从饮用水、牛栏围栏和动物皮肤上采集的样本中检测到该病原体呈阳性。48小时内，来自六个牛栏的30头同组动物中有20头（66%）的皮肤被大肠杆菌O157:H7污染。在引入接种公牛犊3天后，首次检测到未接种同组动物的粪便样本呈阳性。在为期23天的研究中，30头同组动物中有15头至少有一次粪便中排出显著的大肠杆菌O157:H7菌株。使用闭路电视摄像机在12小时内对牛栏内的动物行为进行了监测。摄像机记录显示，每个牛栏每小时平均有13次动物舔舐行为。该研究表明，动物之间大肠杆菌O157:H7的传播可能在摄入低水平病原体后发生，并且动物皮肤可能是一个重要的传播源。
