Animal Health Laboratories, Department of Agriculture and Food Western Australia, South Perth, Western Australia 6151, Australia.
J Clin Microbiol. 2010 Mar;48(3):877-82. doi: 10.1128/JCM.01355-09. Epub 2010 Jan 13.
The Gram-negative anaerobe Dichelobacter nodosus is the primary etiologic agent of ovine footrot. Few studies of the genetic diversity and epidemiology of D. nodosus have been done, despite the economic cost and welfare implications of the disease. This study examined a large collection of Australian isolates; 735 isolates from footrot-infected sheep from 247 farms in Western Australia (WA) were tested by pulsed-field gel electrophoresis (PFGE), and a subset of 616 isolates was tested by infrequent restriction site PCR (IRS-PCR). The genetic diversity of WA isolates was compared to that of 61 isolates from three other Australian states. WA isolates were genetically diverse, with 181 molecular types resolved by PFGE, resulting in a simple diversity ratio (SDR) of 1:4 and a Simpson's index of discrimination value (D) of 0.98. IRS-PCR resolved 77 molecular types (SDR = 1:8 and D = 0.95). The isolates were grouped into 67 clonal groups by PFGE (SDR = 1:11, D = 0.90) and 36 clonal groups by IRS-PCR (SDR = 1:17, D = 0.87). Despite the high genetic diversity, three common clonal groups predominated in WA and were found in other Australian states. On some farms, molecular type was stable over a number of years, whereas on other farms genetically diverse isolates occurred within a flock of sheep or within a hoof. This study provides a large database from which to appropriately interpret molecular types found in epidemiological investigations and to identify common and unknown types that may compromise footrot eradication or control programs.
革兰氏阴性厌氧菌坏死梭杆菌是绵羊腐蹄病的主要病原体。尽管该疾病对经济成本和福利有影响，但对坏死梭杆菌的遗传多样性和流行病学的研究很少。本研究检查了大量澳大利亚分离株；通过脉冲场凝胶电泳（PFGE）测试了来自西澳大利亚州（WA）247 个农场的 735 株来自腐蹄病感染绵羊的分离株，并且通过不频繁的限制性位点 PCR（IRS-PCR）测试了 616 株分离株的亚组。WA 分离株的遗传多样性与来自澳大利亚其他三个州的 61 株分离株进行了比较。WA 分离株具有遗传多样性，通过 PFGE 解析了 181 种分子型，导致简单多样性比（SDR）为 1:4，辛普森鉴别指数值（D）为 0.98。IRS-PCR 解析了 77 种分子型（SDR = 1:8 和 D = 0.95）。通过 PFGE 将分离株分为 67 个克隆群（SDR = 1:11，D = 0.90），通过 IRS-PCR 将分离株分为 36 个克隆群（SDR = 1:17，D = 0.87）。尽管遗传多样性很高，但 WA 中存在三个主要的常见克隆群，并且在其他澳大利亚州也发现了这些克隆群。在一些农场中，分子型多年来保持稳定，而在其他农场中，羊群或蹄部中存在遗传上不同的分离株。本研究提供了一个大型数据库，可从中适当解释流行病学研究中发现的分子型，并识别可能破坏腐蹄病根除或控制计划的常见和未知类型。
