Streptococcus intermedius is a commensal bacterium and a member of the Streptococcus anginosus group. The S. anginosus group, occasionally termed “Streptococcus milleri group” display hemolytic and serologic diversity, yet share core physiological traits. Despite being commensal organisms, members of the S. anginosus group display wide pathogenic potential. S. intermedius has been isolated from patients with periodontitis and fatal purulent infections, especially brain and liver abscesses.