Streptococcus

Microbiology

• Catalase negative Gram-positive coccus in pairs or chains
• Two orthogonal classifications
  • Hemolytic properties on blood agar
    • Alpha: incomplete hemolysis (appears green)
    • Beta: complete hemolysis (appears clear)
    • Gamma: no hemolysis
  • Lancefield antigen group (A-H)

Species

• Streptococcus pneumoniae (alpha-hemolytic, usually in pairs)
• Viridans group streptococci
  • Streptococcus mitis group
    • Streptococcus mitis
    • Streptococcus oralis
    • Streptococcus peroris
    • Streptococcus infantis
    • Streptococcus parasanguinis
    • Streptococcus cristatus
    • Streptococcus gordonii
    • Streptococcus sanguinis
  • Streptococcus salivarius group
    • Streptococcus salivarius
    • Streptococcus vestibularis
    • Streptococcus thermophilus
  • Streptococcus mutans group
    • Streptococcus mutans
    • Streptococcus sobrinus
    • Streptococcus ratti
    • Streptococcus downei
  • Streptococcus anginosus group
    • Streptococcus anginosus
    • Streptococcus constellatus
    • Streptococcus intermedius
• Pyogenic group
  • Streptococcus pyogenes (beta-hemolytic, group A)
  • Streptococcus canis
  • Streptococcus urinalis
  • Streptococcus dysgalactiae (beta-hemolytic, group G)
    • Streptococcus dysgalactiae subspecies dysgalactiae
    • Streptococcus dysgalactiae subspecies equisimilis
  • Streptococcus agalactiae (beta-hemolytic, group B)
  • Streptococcus porcinus
  • Streptococcus parauberis
  • Streptococcus uberis
  • Streptococcus iniae
• Streptococcus bovis group (gamma-hemolytic, Group D)
  • Streptococcus bovis
  • Streptococcus infantarius
  • Streptococcus lutentiensis
  • Streptococcus equinus
  • Streptococcus alactolyticus
  • Streptococcus macedonicus
  • Streptococcus waius
  • Streptococcus pasteurianus
• Other streptococci
  • Streptococcus acidominimus
    • Streptococcus suis
    • Streptococcus ovis
    • Streptococcus equi
  • Nutritionally variant streptococci
    • Granulicatella adiacens
    • Granulicatella paraadiacens
    • Granulicatella elegans
    • Abiotrophia defectiva
  • Previously, Enterococcus spp.