title: Helicobacter equorum sp. nov., a urease-negative Helicobacter species isolated from horse faeces.
abstract: Gram-negative, curved, motile bacteria (strains EqF1T and EqF2) were isolated from faecal samples from two clinically healthy horses. Both strains possessed a single, monopolar, sheathed flagellum and were urease-negative. The novel strains grew at 37 degrees C under microaerobic conditions and were positive for oxidase, catalase and alkaline phosphatase activities. The isolates reduced nitrate to nitrite, but gamma-glutamyl transpeptidase activity was not detected. The novel isolates did not grow at 42 degrees C or on media containing 1 % glycine. They were resistant to cephalotin and nalidixic acid and susceptible to metronidazole. Analysis of the 16S and 23S rRNA gene sequences of the two novel strains identified them as representing a single species within the genus Helicobacter. In terms of 16S rRNA gene sequence similarity, Helicobacter pullorum and Helicobacter canadensis were the most closely related species (98 % similarity). 23S rRNA gene sequence analysis also classified strains EqF1T and EqF2 within the enterohepatic division of the genus Helicobacter, but only 94 % similarity was detected with H. pullorum and H. canadensis, which are helicobacters with unsheathed flagella. The most closely related species in terms of 23S rRNA gene sequence similarity was Helicobacter canis (95 %). Numerical analysis of whole-cell protein extracts by SDS-PAGE was performed and the novel isolates were clearly differentiated from H. pullorum, H. canadensis, H. canis and other species of the genus Helicobacter. This finding was also confirmed by sequence analysis of the hsp60 gene. On the basis of these genetic, biochemical and protein data, the isolates are classified as representing a novel species, for which the name Helicobacter equorum sp. nov. is proposed (type strain EqF1T=LMG 23362T=CCUG 52199T).
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Moyaert
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Decostere
authors.affiliation: Department of Biochemistry, Physiology and Microbiology, Faculty of Sciences, Ghent University, Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Vandamme
authors.affiliation: Department of Biochemistry, Physiology and Microbiology, Faculty of Sciences, Ghent University, Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Debruyne
authors.affiliation: CODA - CERVA - VAR, Groeselenberg 99, B-1180 Brussels, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Mast
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Baele
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Ceelen
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Ducatelle
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Haesebrouck
mesh_terms: D000332:Aerobiosis; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000032:analysis / Q000302:isolation & purification; D018834:Chaperonin 60 / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004798:Enzymes / Q000032:analysis; D005243:Feces / Q000382:microbiology*; D005407:Flagella / Q000502:physiology; D020459:Genes, rRNA / Q000235:genetics; D016998:Helicobacter / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification* / Q000502:physiology; D006736:Horses / Q000382:microbiology*; D008969:Molecular Sequence Data; D009068:Movement; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010802:Phylogeny; D020543:Proteome / Q000032:analysis / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D018834:Chaperonin 60; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D004798:Enzymes; D009566:Nitrates; D009573:Nitrites; D020543:Proteome; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S