streptococcus orisratti streptococcus orisratti streptococcus orisratti is a species of oral streptococcus bacteria first isolated from sprague–dawley rats, hence its name. its type strain is a63t (=atcc 700640t). streptococcus orisratti scientific classification domain: bacteria phylum: bacillota class: bacilli order: lactobacillales family: streptococcaceae genus: streptococcus species: s. orisratti binomial name streptococcus orisrattizhu et al. 2000