title: Intestinal spirochaetes (genus Brachyspira) colonise wild birds in the southern Atlantic region and Antarctica.
abstract: BACKGROUND
  The genus Brachyspira contains well-known enteric pathogens of veterinary significance, suggested agents of colonic disease in humans, and one potentially zoonotic agent. There are recent studies showing that Brachyspira are more widespread in the wildlife community than previously thought. There are no records of this genus in wildlife from the southern Atlantic region and Antarctica. Our aim was therefore, to determine whether intestinal spirochaetes of genus Brachyspira colonise marine and coastal birds in this region.
  
  
  METHODS
  Faecal samples were collected from marine and coastal birds in the southern Atlantic region, including sub-Antarctic islands and Antarctica, in 2002, 2009, and 2012, with the aim to isolate and characterise zoonotic agents. In total, 205 samples from 11 bird species were selectively cultured for intestinal spirochaetes of genus Brachyspira. To identify isolates to species level, they were subjected to phenotyping, species-specific polymerase chain reactions, sequencing of partial 16S rRNA, NADH oxidase (nox), and tlyA genes, and phylogenetic analysis. Antimicrobial susceptibility tests were performed.
  
  
  RESULTS
  Fourteen unique strains were obtained from 10 birds of three species: four snowy sheathbills (Chionis albus), three kelp geese (Chloephaga hybrida subsp. malvinarum), and three brown skua (Stercorarius antarcticus subsp. lonnbergi) sampled on the Falkland Islands, Tierra del Fuego in Argentina, South Georgia, South Shetland Islands, and the Antarctic Peninsula. Five Brachyspira strains were closely related to potentially enteropathogenic Brachyspira sp. of chickens: B. intermedia (n=2, from snowy sheathbills), and B. alvinipulli (n=3, from a kelp goose and two snowy sheathbills). Three strains from kelp geese were most similar to the presumed non-pathogenic species 'B. pulli' and B. murdochii, whereas the remaining six strains could not be attributed to currently known species. No isolates related to human strains were found. None of the tested strains showed decreased susceptibility to tiamulin, valnemulin, doxycycline, tylvalosin, lincomycin, or tylosin.
  
  
  CONCLUSIONS
  This is the first report of intestinal spirochaetes from this region. Despite limitations of current diagnostic methods, our results, together with earlier studies, show that Brachyspira spp., including potentially pathogenic strains, occur globally among free-living avian hosts, and that this genus encompasses a higher degree of biodiversity than previously recognised.
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, Uppsala, Sweden; desiree.jansson@sva.se.
authors.forename: Désirée S
authors.initials: DS
authors.lastname: Jansson
authors.affiliation: Department of Animal Breeding and Genetics, Global Bioinformatics Centre, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
authors.forename: Memoona
authors.initials: M
authors.lastname: Mushtaq
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Karl-Erik
authors.initials: KE
authors.lastname: Johansson
authors.affiliation: Department of Infectious Diseases, Kalmar County Hospital, Kalmar, Sweden.|Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Bonnedahl
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Waldenström
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: Dan I
authors.initials: DI
authors.lastname: Andersson
authors.affiliation: Division of CBRN Defence and Security, FOI - Swedish Defence Research Agency, Umeå, Sweden.
authors.forename: Tina
authors.initials: T
authors.lastname: Broman
authors.affiliation: Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Berg
authors.affiliation: Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Olsen
keywords: Antarctica; Brachyspira; antimicrobial susceptibility; brown skua; intestinal spirochaete; kelp goose; phylogeny; snowy sheathbill; southern Atlantic region; sub-Antarctic islands