Tamminen Lena-Mari, Dicksved Johan, Eriksson Erik, Keeling Linda J, Emanuelson Ulf
Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Infect Ecol Epidemiol. 2024 Oct 8;14(1):2406852. doi: 10.1080/20008686.2024.2406852. eCollection 2024.
Cattle colonised by the zoonotic pathogen verotoxin-producing Escherichia coli of serotype O157 (VTEC O157) can shed high levels of the pathogen in their faeces. A suggested key for controlling VTEC O157 is preventing colonisation of individuals. In this study the role of individual super-shedders and factors related to susceptibility and environmental exposure in the transmission of VTEC O157 among dairy calves are explored. The association between sex, age, pen hygiene, pen type and stocking density and colonisation of individual calves, established by recto-anal mucosal swabs, on farms where pathogenic VTEC O157 had been confirmed was investigated. In a follow-up sampling, the consistency of previously identified risk factors and the role of shedding pen mates was assessed by studying the risk of new/re-colonisation. The results suggest an important role of stocking density that decreases with age, possibly due to increased resistance to colonisation following exposure. However, previous colonisation did not influence the risk of being colonised in the second sampling. Super-shedders (shedding >103 colony forming units/g faeces) significantly increased the risk of colonisation in peers (OR = 10, CI 4.2-52). In addition, environmental factors associated with survival of the bacteria, affected risk. The results confirm the suggested importance of super-shedders but also emphasises the importance of considering the combined exposure from peers and the environment.
被血清型为O157的产志贺毒素大肠杆菌（VTEC O157）这种人畜共患病原体定植的牛，会在粪便中排出大量该病原体。控制VTEC O157的一个关键建议是防止个体被定植。在本研究中，探讨了个体超级排菌者以及与易感性和环境暴露相关的因素在VTEC O157在奶牛犊牛间传播中的作用。在已确认存在致病性VTEC O157的农场中，通过直肠肛门黏膜拭子确定个体犊牛的性别、年龄、栏舍卫生、栏舍类型和饲养密度与定植之间的关联。在后续采样中，通过研究新定植/再定植的风险，评估先前确定的风险因素的一致性以及排菌同伴的作用。结果表明饲养密度起着重要作用，且随着年龄增长而降低，这可能是由于暴露后对定植的抵抗力增强。然而，先前的定植并未影响第二次采样时被定植的风险。超级排菌者（粪便中排菌>103菌落形成单位/克）显著增加了同伴被定植的风险（比值比=10，置信区间4.2 - 52）。此外，与细菌存活相关的环境因素也影响风险。结果证实了超级排菌者的重要性，但也强调了考虑来自同伴和环境的综合暴露的重要性。
