streptococcus ratti streptococcus ratti streptococcus ratti is a species of streptococcus. streptococcus ratti can be viewed as a type of oral bacteria. it is a type of bacteria that may be found in healthy individuals. one example may be oral cavities. streptococcus ratti is also a component of dental biofilms. streptococcus ratti scientific classification domain: bacteria phylum: bacillota class: bacilli order: lactobacillales family: streptococcaceae genus: streptococcus species: s. ratti binomial name streptococcus ratticoykendall 1977