Streptococcus pyogenes (Group A)

Streptococcus pyogenes (Group A) is a topic covered in the Johns Hopkins ABX Guide.

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MICROBIOLOGY

  • Group A Streptococcus (GAS), beta-hemolytic--grows on blood agar. See Streptococcal species or S. pneumoniae modules for other streptococci.
    • Streptococcus pyogenes, Lancefield group A.
    • Gram-positive cocci in chains [Fig 1].
  • Ecologic niches are pharynx, genital mucosa and skin; colonization rates:
    • Adults 2-3%
    • School children 15-20%
  • Virulence depends on proteins that represent toxins, mimic host macromolecules and after immune responses.
    • M protein gene (emm) ~100 serotypes
      • May be used to track outbreaks, public health tracking of invasive infections
      • Certain types (emm1, emm3, emm4, emm6, emm12, emm18, emm89) associated with most cases of invasive infections.

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Last updated: August 9, 2019