INCIDENCE AND GRAVITY: Invasive Streptococcus pyogenes infections are a common reason for hospitalization. Serious forms may occur in patients with no known risk factor, including young patients. Inversely, erysipela is observed more readily in the elderly population with a more vulnerable venous system. Disease gravity is related to the high risk of recurrence. For cellulitis, predominantly a disease of young subjects with no past history, severity is related to local extension and development of shock syndrome. Besides the immediate life-threatening situation, functional prognosis may be compromised, depending on the localization of the infection.
Pathogenesis of group a streptococcal infections: Adherence and invasion properties of group A streptococci, particularly the capsule and protein M, as well as streptococcal toxins cause severe septic and toxinic syndromes. Strains most frequently associated with invasive infections are: biotype 1, serotype M1 and biotype 3, serotype M3.
Treatment: An antibiotic regimen by intravenous infusion of penicillin G is the gold standard treatment. Clindamycin should be added in case of septic shock. Extensive cellulitis or necrotizing fasciitis requires surgical debridement of the necrotic tissue and intensive care for the shock syndrome.