Streptococcus Pyogenes
TAXONOMY
Domain: Bacteria
Phylum: Bacillota (Firmicutes)
Class: Bacilli
Order: Lactobacillales
Family: Streptococcaceae
Species: Streptococcus pyogenes
MORPHOLOGY
Gram‑positive cocci in chains, catalase‑negative
Non‑motile, non‑spore‑forming; encapsulated with hyaluronic acid
β‑hemolytic on blood agar (complete red blood cell lysis)
Capable of biofilm formation, particularly in chronic or recurrent infections (well‑documented in GAS literature)
NOTABLE TRAITS
Facultative anaerobe (aerotolerant) thriving at ~35–37 °C; catalase‑negative
Virulence factors include M protein, streptolysins O & S, DNases, pyrogenic exotoxins (SpeA, SpeB), streptokinase, hyaluronidase
Usually penicillin‑sensitive; growing macrolide resistance via erm/mef genes (multiple surveillance studies ongoing)
Molecular mimicry by M protein contributes to immune evasion and post‑infectious sequelae
