title: Characterization and Recognition of Brachyspira hampsonii sp. nov., a Novel Intestinal Spirochete That Is Pathogenic to Pigs.
abstract: Swine dysentery (SD) is a mucohemorrhagic colitis of swine classically caused by infection with the intestinal spirochete Brachyspira hyodysenteriae Since around 2007, cases of SD have occurred in North America associated with a different strongly beta-hemolytic spirochete that has been molecularly and phenotypically characterized and provisionally named "Brachyspira hampsonii." Despite increasing international interest, B. hampsonii is currently not recognized as a valid species. To support its recognition, we sequenced the genomes of strains NSH-16T, NSH-24, and P280/1, representing B. hampsonii genetic groups I, II, and III, respectively, and compared them with genomes of other valid Brachyspira species. The draft genome of strain NSH-16Thas a DNA G+C content of 27.4% and an approximate size of 3.2 Mb. Genomic indices, including digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), and average amino acid identity (AAI), clearly differentiated B. hampsonii from other recognized Brachyspira species. Although discriminated genotypically, the three genetic groups are phenotypically similar. By electron microscopy, cells of different strains of B. hampsonii measure 5 to 10 μm by 0.28 to 0.34 μm, with one or two flat curves, and have 10 to 14 periplasmic flagella inserted at each cell end. Using a comprehensive evaluation of genotypic (gene comparisons and multilocus sequence typing and analysis), genomic (dDDH, ANI, and AAI) and phenotypic (hemolysis, biochemical profiles, protein spectra, antibiogram, and pathogenicity) properties, we classify Brachyspira hampsonii sp. nov. as a unique species with genetically diverse yet phenotypically similar genomovars (I, II, and III). We designate the type strain NSH-16 (= ATCC BAA-2463 = NCTC 13792).
authors.affiliation: Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Nandita S
authors.initials: NS
authors.lastname: Mirajkar
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Nyree D
authors.initials: ND
authors.lastname: Phillips
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Tom
authors.initials: T
authors.lastname: La
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Hampson
authors.affiliation: Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA gebha001@umn.edu.|Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, USA.
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Gebhart
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D017400:Brachyspira / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure; D003092:Colitis / Q000382:microbiology / Q000662:veterinary*; D004403:Dysentery / Q000382:microbiology / Q000662:veterinary*; D016680:Genome, Bacterial / Q000235:genetics*; D008854:Microscopy, Electron; D058885:Multilocus Sequence Typing; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S