title: Fecal shedding of Brachyspira spp. on a farrow-to-finish swine farm with a clinical history of "Brachyspira hampsonii"-associated colitis.
abstract: BACKGROUND
  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".
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Patterson
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Rubin
authors.forename: Champika
authors.initials: C
authors.lastname: Fernando
authors.forename: Matheus O
authors.initials: MO
authors.lastname: Costa
authors.forename: John C S
authors.initials: JC
authors.lastname: Harding
authors.forename: Janet E
authors.initials: JE
authors.lastname: Hill
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D057138:Bacterial Shedding; D001483:Base Sequence; D017400:Brachyspira / Q000235:genetics / Q000502:physiology*; D003092:Colitis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D003430:Cross-Sectional Studies; D005243:Feces / Q000382:microbiology; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012525:Saskatchewan / Q000453:epidemiology; D013552:Swine / Q000382:microbiology; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology*