Streptococcus pyogenes ( Group A Streptococcus )

Group A streptococcus (GAS) is synonymous with Streptococcus pyogenes, the only species within this group of β-hemolytic streptococci. GAS is one of the leading pathogenic bacteria that infects children and adolescents, and is associated with a wide spectrum of infections and disease states. Worldwide, there are estimated to be >600 million cases of GAS pharyngitis (“strep throat”) and >100 million cases of GAS pyoderma annually. Although uniformly susceptible to penicillin and still exquisitely susceptible to many other antimicrobial agents, GAS infections continue to present formidable clinical and public health challenges. The vast majority of GAS infections are of short duration and are relatively benign; however, invasive disease can be fulminant and life-threatening. In addition, GAS differs from other pyogenic bacteria in their potential to produce delayed, nonsuppurative sequelae (e.g., poststreptococcal acute glomerulonephritis (PSAGN) and acute rheumatic fever (ARF)) following uncomplicated infections. The importance of GAS infections in the United States was re inforced at the close of the 20th century by a resurgence of ARF as well as by the appearance of severe invasive GAS infections (e.g., streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis) with high morbidity and mortality. On the global scale, GAS is an important cause of morbidity and mortality primarily in developing countries, with >500,000 deaths annually.