Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, N-0033 Oslo, Norway.
Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway.
Vet Microbiol. 2014 Jun 4;170(3-4):375-82. doi: 10.1016/j.vetmic.2014.02.044. Epub 2014 Mar 12.
Dichelobacter nodosus is the main aetiological agent of ovine footrot and the bacterium has also been associated with interdigital dermatitis is cattle. The aim of this study was to investigate possible cross-infection of virulent D. nodosus between sheep and co-grazing cattle. Five farms, where sheep previously diagnosed with virulent D. nodosus were co-grazing with cattle for different periods of time, were included. The study sample consisted of 200 cows and 50 sheep. All cows were examined for the presence of interdigital dermatitis, and ten ewes, preferably with symptoms of footrot, had the footrot scores recorded. On each farm, the same ten ewes and ten cows were chosen for bacterial analyses. Swabs were analysed for D. nodosus by PCR and culturing. D. nodosus isolates were virulence-tested and assigned to serogroups by fimA variant determination. Biopsies were evaluated histopathologically and analysed by fluorescent in situ hybridization for D. nodosus, Treponema spp. and Fusobacterium necrophorum. D. nodosus defined as virulent by the gelatin gel test were isolated from 16 sheep from four farms and from five cows from two of the same farms. All five cows had interdigital dermatitis. Two of the cows stayed infected for at least eight months. By pulsed-field gel electrophoresis (PFGE), the isolates from the five cows were found to be genetically indistinguishable or closely related to isolates from sheep from the same farm. This indicates that cross-infection between sheep and cows have occurred.
化脓隐秘杆菌是绵羊腐蹄病的主要病原体，该细菌也与牛的趾间皮炎有关。本研究旨在调查毒力化脓隐秘杆菌是否可能在绵羊和共同放牧的牛之间发生交叉感染。共纳入了五个农场，这些农场的绵羊曾被诊断为感染了毒力化脓隐秘杆菌，并且与牛共同放牧了不同的时间。研究样本包括 200 头牛和 50 只绵羊。所有牛都检查了是否存在趾间皮炎，并且 10 只最好有腐蹄病症状的母羊记录了腐蹄病评分。在每个农场，都选择了相同的 10 只母羊和 10 头牛进行细菌分析。通过 PCR 和培养分析拭子中是否存在化脓隐秘杆菌。对化脓隐秘杆菌分离株进行毒力测试，并通过 fimA 变体确定将其分配到血清群。对活检进行组织病理学评估，并通过荧光原位杂交分析化脓隐秘杆菌、密螺旋体属和坏死梭杆菌。从四个农场的 16 只绵羊和两个相同农场的五只牛中分离出了通过明胶凝胶试验定义为毒力的化脓隐秘杆菌。所有五头牛都患有趾间皮炎。其中两头牛至少感染了八个月。通过脉冲场凝胶电泳 (PFGE)，发现来自五头牛的分离株在遗传上无法区分或与来自同一农场绵羊的分离株密切相关。这表明绵羊和牛之间发生了交叉感染。
