title: Phylogenetic characterization of 'Candidatus Helicobacter bovis', a new gastric helicobacter in cattle.
abstract: Recently helicobacter-like organisms have been reported in the pyloric part of the abomasum of calves and adult cattle. Cultivation of these spiral bacteria has not been successful to date. In the present study, comparative 16S rDNA sequence analysis was used to determine the taxonomic position of these bacteria. Seven abomasal biopsies of adult cattle were sampled from different Belgian and Dutch farms. In all samples the presence of helicobacter-like organisms was demonstrated by biochemical, immunohistochemical and electron microscopical data. Bacterial 16S rDNA was amplified by PCR and sequences were determined either by direct or indirect sequence analysis. Pairwise comparisons revealed all sequences to be more than 99% homologous. Phylogenetic analysis placed the organism, corresponding to the reference sequence R2XA, within the genus Helicobacter. A diagnostic PCR assay was designed, differentiating all of the bovine 16S rDNA sequences from Helicobacter and Wolinella species. The low similarity level towards Helicobacter bilis (92.8%), its closest validly named neighbour, indicates that this novel taxon is indeed a novel Helicobacter species. An in situ hybridization procedure associated the bovine sequences to the helicobacter-like organisms in the abomasum. The name 'Candidatus Helicobacter bovis' is proposed for this new abomasal helicobacter from cattle.
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium. dominic.degroote@rug.ac.be
authors.forename: D
authors.initials: D
authors.lastname: De Groote
authors.forename: L J
authors.initials: LJ
authors.lastname: van Doorn
authors.forename: R
authors.initials: R
authors.lastname: Ducatelle
authors.forename: A
authors.initials: A
authors.lastname: Verschuuren
authors.forename: K
authors.initials: K
authors.lastname: Tilmant
authors.forename: W G
authors.initials: WG
authors.lastname: Quint
authors.forename: F
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: P
authors.initials: P
authors.lastname: Vandamme
mesh_terms: D000018:Abomasum / Q000382:microbiology*; D000818:Animals; D002417:Cattle / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D016998:Helicobacter / Q000145:classification* / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D017403:In Situ Hybridization; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014510:Urease / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D014510:Urease