Introduction
Streptococcus intermedius is a beta-hemolytic, non-motile, catalase-negative, gram-positive member of the Streptococcus anginosus group (SAG), along with S. anginosus and S. constellatus [1,2]. This group is part of the normal human microbiota in the respiratory, gastrointestinal, and genitourinary tracts [1]. They can cause purulent infections and abscesses in the heart, brain, liver, lungs, spleen, peritoneum, and appendix [1,3]. S. intermedius is the most pathogenic of the group, having significantly longer hospital stays compared to S. anginosus and significantly higher mortality rates than S. constellatus [1, 4]. Its high-grade pathogenicity allows it to cause an abscess in multiple sites, particularly the brain and liver due to its apparent tropism to these sites [5,6]. A 2020 study that collected data on patients with culture-positive SAG from the bacterial laboratory database of the Affiliated Hospital of Jining Medical University Hospital and Jining No. 1 People’s Hospital showed that the three different organisms in this group were predominantly found in different age groups and different locations [7]. S. interermedius was mostly found in patients aged 65 years old and above and was more likely to produce cranial infections [7]. It is more commonly seen in males, with a male: female ratio of about 2:1, and the highest number of reported cases are in the United States [1]. S. constelatus was mostly found in patients aged 35-54 years old and was more likely to produce chest infections, and S. anginosus was mostly found in patients aged 18-34 years old and was more likely to produce perianal abscesses [7].