peptostreptococcus stomatis peptostreptococcus stomatis peptostreptococcus stomatis is a bacterium from the family peptostreptococcaceae. peptostreptococcus stomatis scientific classification domain: bacteria phylum: bacillota class: clostridia order: eubacteriales family: peptostreptococcaceae genus: peptostreptococcus species: p. stomatis binomial name peptostreptococcus stomatisdownes and wade 2006