streptococcus infantarius streptococcus infantarius streptococcus infantarius is a species of bacteria. streptococcus infantarius scientific classification domain: bacteria phylum: bacillota class: bacilli order: lactobacillales family: streptococcaceae genus: streptococcus species: s. infantarius binomial name streptococcus infantariusschlegel et al. 2000 subspecies streptococcus infantarius subsp. coli schlegel et al. 2000 streptococcus infantarius subsp. infantarius natural genetic transformation s. infantarius is competent for natural genetic transformation. competence can be induced in cultures at high cell density, and is transient.