Reclassification of Arachnia propionica as Propionibacterium propionicus comb. nov.

Abstract
The phylogenetic position of Arachnia propionica was determined by using reverse transcriptase sequencing of long regions of 16S ribosomal ribonucleic acid. Arachnia propionica formed a distinct group with Propionibacterium freudenreichii and Propionibacterium acnes but was unrelated to members of the genus Actinomyces. The retention of Arachnia as a separate genus is unjustified. On the basis of the present analysis and previous chemotaxonomic evidence, we propose that Arachnia propionica be reclassified in the genus Propionibacterium as Propionibacterium propionicus (Buchanan and Pine) comb. nov.