Streptococcus pyogenes M1 GAS

The group A streptococci (GAS, Streptococcus pyogenes) are gram-positive, nonmotile, nonsporeforming coccus that occur in chains or in pairs of cells. Individual cells are round-to-ovoid cocci, 0.6-1.0 micrometer in diameter. They are catalase-negative aerotolerant anaerobe (facultative anaerobe) which require enriched medium containing blood in order to grow. Their capsule is composed of hyaluronic acid. GAS are important human pathogens which can cause a variety of diseases, ranging from mild infections to very severe invasive diseases. The M protein is a highly polymorphic cell-surface molecule that is antiphagocytic and forms the basis of a scheme commonly used to classify GAS strains. Serotype M3 strains cause a higher rate of lethal infections than strains of other M types. In addition, serotype M3 and other GAS strains can undergo rapid shifts in disease frequency and display epidemic behaviour. Strict human pathogen responsible for a wide variety of diseases, including pharyngitis, scarlet fever, impetigo, septicemia, toxic shock syndrome, flesh-eating disease, rheumatic fever and acute glomerulonephritis. MGAS5005 was isolated in 1996 from the cerebrospinal fluid of an infected patient in Ontario, Canada, and has been used extensively in studies of GAS pathogenesis. (EBI Integr8)