Streptococcus Anginosus Group (SAG)


  • Streptococcus anginosus group was formerly called the Strep milleri group


  • Members of Viridans Group Strep (VGS) (see Viridans Group Streptococci, [[Viridans Group Streptococci]]): these typically are Vancomycin-sensitive
    • Strep anginosus Group
      • Strep anginosus
      • Strep constellatus
      • Strep intermedius
    • Strep mitis Group (see Streptococcus Mitis Group, [[Streptococcus Mitis Group]])
      • Strep mitis
      • Strep gordonii
      • Strep oralis
      • Strep sanguis
      • Strep parasanguis
    • Strep salivarius Group (see Streptococcus Salivarius Group, [[Streptococcus Salivarius Group]])
      • Strep salivarius
      • Strep thermophilus
      • Strep vestibularis
    • Strep bovis Group (see Streptococcus Bovis Group, [[Streptococcus Bovis Group]])
      • Strep bovis
      • Strep equinus
      • Strep alactolyticus
    • Strep mutans Group (see Streptococcus Mutans Group, [[Streptococcus Mutans Group]])
      • Strep mutans
      • Strep rattus
      • Strep cricetus
      • Strep downei
      • Strep sobrinus
      • Strep macacae


  • Organisms
    • Strep anginosus: isolated from larger range of sites
    • Strep constellatus: isolated from larger range of sites
    • Strep intermedius: tropism for brain and liver
  • Commensal Organisms
    • Oropharynx
    • Gastrointestinal Tract
    • Vaginal Flora
    • Skin


  • PCR-Based Methods: usually necessary to idnetify organism
    • Difficult to diagnose based on phenotypic characteristics

Clinical Manifestations

General Comments

  • May Manfest Extension Across Tissue Planes: including interlobar fissure, diaphragm, and chest wall
    • This is a unique characteristic

Cardiovascular Manifestations

  • Endocarditis (see xxxx, [[Endocarditis]]): less commonly associated than other viridans group strep species
    • Strep intermedius rarely causes endocarditis

Gastrointestinal Manifestations

Neurologic Manifestations

Pulmonary Manifestations


  • Streptococcus anginosus infections: crossing tissue planes. Chest. 2014 Oct;146(4):e121-5. doi: 10.1378/chest.13-2791 [MEDLINE]