The contribution of group A streptococcal virulence determinants to the pathogenesis of sepsis

Streptococcus pyogenes (group A streptococcus, GAS) is responsible for a wide range of pathologies ranging from mild pharyngitis and impetigo to severe invasive soft tissue infections. Despite the continuing susceptibility of the bacterium to β-lactam antibiotics there has been an unexplained resurgence in the prevalence of invasive GAS infection over the past 30 years. Of particular importance was the emergence of a GAS-associated sepsis syndrome that is analogous to the systemic toxicosis associated with TSST-1 producing strains of Staphylococcus aureus. Despite being recognized for over 20 years, the etiology of GAS associated sepsis and the streptococcal toxic shock syndrome remains poorly understood. Here we review the virulence factors that contribute to the etiology of GAS associated sepsis with a particular focus on coagulation system interactions and the role of the superantigens in the development of streptococcal toxic shock syndrome.