Invasive group A streptococcal infections

Beginning in the mid-1980s and continuing to the present, there has been an apparent increase in the number of severe group A streptococcal infections and their suppurative and nonsuppurative sequelae. The reasons for this epidemiologic change remain incompletely explained. At present, the data seem to suggest that this change is related to the reappearance in the population of not only "new" serotypes, but most likely virulent strains of these serotypes. This has been suggested by available epidemiologic surveys. The pathogenetic mechanism by which these virulent strains cause an increased severity of disease is also incompletely understood. It has been suggested that certain of the streptococcal pyrogenic exotoxins (pyrogenic exotoxin A or B) are associated with strains isolated from severe cases of systemic group A streptococcal infections, but the data conflict in many instances. Clinically, this is an extraordinarily virulent syndrome often leading to the death of the patient within a matter of hours or days. This is despite what would seem to be adequate and appropriate antimicrobial therapy with agents which are effective in vitro against the offending group A streptococcus. Therapy therefore is still based on appropriate antibiotic therapy and support of other systemic manifestations with appropriate medical therapy. At present, prevention of these suppurative and nonsuppurative sequelae is impractical simply because the initial streptococcal infection or colonization is rarely recognized. These events of the last half decade strongly support the need for additional understanding of the epidemiology, pathogenesis, treatment, and prevention of serious group A beta-hemolytic streptococcal infections.