Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
BMC Vet Res. 2013 Jul 11;9:137. doi: 10.1186/1746-6148-9-137.
Brachyspira associated diarrhea is a re-emerging concern for Canadian swine producers. To identify critical control points for reducing the impact of Brachyspira on production, improved diagnostic tools and a better understanding of the on-farm epidemiology of these pathogens are required. A cross-sectional study was conducted for the detection of Brachyspira on a commercial, two-site, farrow-to-finish pork production unit in Saskatchewan, Canada with a clinical history of mucohaemorrhagic colitis associated with "B. hampsonii".
Rectal swabs from pigs at all production stages were collected over 13 weeks (n=866). Two swabs were collected per pig for culture and Gram stain, and for PCR. Ninety-one culture positive samples were detected, with the highest prevalence of Brachyspira shedding in grower pigs (21%). No Brachyspira were detected in pre-weaned piglets. PCR and Gram stain of rectal swabs detected fewer positive samples than culture. The most prevalent species detected was B. murdochii; other species detected included B. pilosicoli, B. innocens, and "Brachyspira hampsonii". Phylogenetic analysis revealed that several of the isolates, including some strongly beta-haemolytic isolates, might represent novel taxa.
Our results indicate that apparently healthy pigs can be colonized with diverse Brachyspira species, including some potential pathogens, and that frequency of shedding peaks in the grower stage. Difference in the detection rates of Brachyspira amongst culture, Gram stain or PCR on rectal swabs have implications for choice of detection methods and surveillance approaches that may be most effective in Brachyspira control strategies.
布拉迪斯拉维亚相关腹泻是加拿大养猪生产者重新关注的问题。为了确定减少布拉迪斯拉维亚对生产影响的关键控制点，需要改进诊断工具并更好地了解这些病原体在农场的流行病学。在加拿大萨斯喀彻温省的一个商业、两阶段、从分娩到育肥的猪肉生产单位进行了一项横断面研究，该单位有临床病史为与“B. hampsonii”相关的黏液血性结肠炎的布拉迪斯拉维亚感染。
在 13 周的时间内，从所有生产阶段的猪中采集直肠拭子（n=866）。每头猪采集两个拭子进行培养和革兰氏染色以及 PCR。检测到 91 个培养阳性样本，生长猪的布拉迪斯拉维亚脱落率最高（21%）。未检测到断奶前仔猪的布拉迪斯拉维亚。PCR 和直肠拭子的革兰氏染色检测到的阳性样本比培养少。检测到的最常见物种是 B. murdochii；其他检测到的物种包括 B. pilosicoli、B. innocens 和“Brachyspira hampsonii”。系统发育分析表明，包括一些强β溶血分离株在内的几个分离株可能代表新的分类群。
我们的结果表明，看似健康的猪可能会定植多种布拉迪斯拉维亚物种，包括一些潜在的病原体，并且在生长阶段脱落的频率最高。直肠拭子培养、革兰氏染色或 PCR 检测布拉迪斯拉维亚的检出率差异可能对检测方法和监测方法的选择有影响，这些方法可能在布拉迪斯拉维亚控制策略中最有效。
