Characterization of some Actinomyces-like isolates from human clinical specimens: reclassification of Actinomyces suis (Soltys and Spratling) as Actinobaculum suis comb. nov. and description of Actinobaculum schaalii sp. nov

Int J Syst Bacteriol. 1997 Jul;47(3):899-903. doi: 10.1099/00207713-47-3-899.


Five strains of a hitherto unknown Actinomyces-like bacterium were isolated from human clinical sources, including blood cultures. Biochemical and chemotaxonomic characterization indicated that the strains were distinct from previously described Actinomyces and Arcanobacterium species. A comparative 16S rRNA gene sequence analysis demonstrated that the undescribed strains constitute a new subline within the Actinomyces-Arcanobacterium species complex. The closest known relative of the isolates was found to be Actinomyces suis, although a 16S rRNA sequence divergence value of approximately 6% clearly demonstrated that the unknown bacterium represents a distinct species. Based on the results of the present and earlier phylogenetic investigations, it is proposed that Actinomyces suis should be reclassified in a new genus, the genus Actinobaculum, as Actinobaculum suis comb. nov. In addition, a new species, Actinobaculum schaalii, is proposed for the Actinomyces-like bacterium from human sources. The type strain of Actinobaculum schaalii is CCUG 27420.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinomyces / chemistry
  • Actinomyces / classification*
  • Actinomyces / metabolism
  • Actinomycosis / microbiology*
  • Bacterial Proteins / analysis
  • Blood / microbiology
  • Humans
  • Molecular Sequence Data
  • Phylogeny


  • Bacterial Proteins

Associated data

  • GENBANK/Y12329