prevotella bryantii prevotella bryantii prevotella bryantii, previously known as bacteroides ruminicola ruminicola subsp. brevis biovar 3, is a species of bacterium. prevotella bryantii scientific classification domain: bacteria phylum: bacteroidota class: bacteroidia order: bacteroidales family: prevotellaceae genus: prevotella species: p. bryantii binomial name prevotella bryantiiavgustin et al. 1997 prevotella species are part of the human oral and vaginal microbiota. they play a role in the pathogenesis of periodontal disease, gingivitis, extraoral and some odontogenic infections, and strains are usually carried in families, in so-called intrafamilial carriage. it is also associated with carotid atherosclerosis.