porphyromonas somerae porphyromonas somerae porphyromonas somerae is a gram-negative and anaerobic bacterium from the genus of porphyromonas which has been isolated from a human leg ulcer in the united states. porphyromonas somerae scientific classification domain: bacteria phylum: bacteroidota class: bacteroidia order: bacteroidales family: porphyromonadaceae genus: porphyromonas species: p. somerae binomial name porphyromonas someraesummanen et al. 2006 type strain atcc baa-1230, ccug 51464, jcm 13867, wal 6690