Invasive group A streptococcal diseases and pyrogenic exotoxins A and B: an update on pathogenesis and management

Since the mid-1980s, there have been increasing numbers of reports on the r esurgence of severe invasive group A streptococcal infections world-wide. D espite prompt therapy with penicillin and/or clindamycin, the mortality rat es of these infections, including streptococcal toxic shock-like syndrome, remain high. Among the many virulence factors pyrogenic exotoxins A (SPE-A) and B (SPE-B), associated with certain virulent serotypes including M1 and M3 strains, have been implicated in the pathogenesis of serious streptococ cal manifestations. The biological effects of SPE-A and SPE-B in vitro as w ell as in vivo are summarised and the implications for the pathogenesis and treatment of invasive group A streptococcal diseases are discussed. (C) 20 00 Lippincott Williams & Wilkins.