IE is most commonly caused by viridans group of streptococci (VGS) in the indian subcontinent. The taxonomy of VGS is evolving. The species that most commonly cause IE are S. sanguis, S. oralis (mitis), S. salivarius, S. mutans, and Gemella morbillorum (formerly called S. morbillorum). Members of the S. anginosus group (S. intermedius, anginosus, and constellatus) also have been referred to as the S milleri group, and this has caused some confusion. In contrast to other α-hemolytic streptococcal species, the S. anginosus group tends to form abscesses and to cause hematogenously disseminated infection (eg, myocardial and visceral abscesses, septic arthritis, and vertebral osteomyelitis). The recommendations are intended to assist clinicians in selecting appropriate antimicrobial therapy for patients with IE caused by VGS and S. gallolyticus (bovis, a nonenterococcal penicillin-susceptible group D Streptococcus) (Table 4). S. gallolyticus (bovis) expresses the group D antigen, but it can be distinguished from group D Enterococcus by appropriate biochemical tests. Patients with either S gallolyticus (bovis) bacteremia or IE should undergo a colonoscopy to determine whether malignancy or other mucosal lesions are present.

Antibiotic therapy for native valve IE due to VGS and group D streptococci, Streptococcus gallolyticus (Formerly Known as Streptococcus bovis), Abiotrophia defectiva, and Granulicatella Species