Proposal of Histophilus somni gen. nov., sp nov for the three species incertae sedis 'Haemophilus somnus', 'Haemophilus agni' and 'Histophilus ovis'

Øystein Angen, Peter Ahrens, P. Kuhnert, H. Christensen, R. Mutters

    Research output: Contribution to journalJournal articleResearchpeer-review


    Earlier investigations have shown that 'Haemophilus somnus','Haemophilus agni' and' Histophilus ovis' represent the same species. In the present investigation, the taxonomic position of this species is explored further by sequencing the 16S rRNA and rpoB genes of strains that were investigated previously by DNA-DNA hybridization. These results clearly support the allocation of this species to a novel genus within the family Pasteurellaceae. The phenotypic separation of Histophilus somni gen. nov., sp. nov. from other members of the family can, for most strains, be based on capnophilia, yellowish pigmentation and indole production. However, due to phenotypic variation, the use of a species-specific PCR test based on the 16S rRNA gene is included in the species description. This is justified by the high sequence similarity of the 16S rRNA gene within the species and the fact that the highest sequence similarity to any other taxon within the family is 93.4%. The type strain, 8025(T) = ATCC 43625(T) CCUG 36157(T), was isolated in the USA from a bovine brain with lesions of thromboembolic meningoencephalitis.
    Original languageEnglish
    JournalInternational Journal of Systematic and Evolutionary Microbiology
    Issue number5
    Pages (from-to)1449-1456
    Publication statusPublished - 2003

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