S Pyogenes Virulence Factors 1. Structural Components carbohydrate-based bacterial capsule composed of hyaluronic acid M protein inhibit opsonization poteichoic acid and protein F(Sfbl)allow attachment to various host cells 2. Toxins and Superantigens Streptolysin O is a exotoxin of beta hemolytic Group property Streptolysin S is a cardiotoxic exotoxin that is another beta hemolytic component EXotoxin A, B, and c are superantigens cause sTss and scarlet fever 3. Enzymes
S. Pyogenes Virulence Factors 1. Structural Components – carbohydrate-based bacterial capsule composed of hyaluronic acid – M protein inhibit opsonization – lipoteichoic acid and protein F (SfbI) allow attachment to various host cells 2. Toxins and Superantigens – Streptolysin O is a exotoxin of beta hemolytic Group property – Streptolysin S is a cardiotoxic exotoxin that is another betahemolytic component – Exotoxin A, B, and C are superantigens cause STSS and scarlet fever 3. Enzymes
S Pyogenes Virulence Factors Streptokinase digest fibrin and other proteins Hyaluronidase breaks down hyaluronic acid in connective tissue allowing spread Streptodornase are DNAses C5a Peptidase are used to minimize influx of neutrophils early in infection
S. Pyogenes Virulence Factors – Streptokinase digest fibrin and other proteins – Hyaluronidase breaks down hyaluronic acid in connective tissue allowing spread – Streptodornase are DNAses – C5a Peptidase are used to minimize influx of neutrophils early in infection
Streptococcus Pyogenes Pathogenesis Serious infection of Beta-hemolytic group A s pyogenes can results in bacteremia with sepsis, which is rapidly fatal Usually involve rapidly spreading infection along lymphatics with little focal suppuration From lymphatics infection can spread via blood stream
Streptococcus Pyogenes Pathogenesis • Serious infection of Beta-hemolytic group A S.pyogenes can results in bacteremia with sepsis, which is rapidly fatal • Usually involve rapidly spreading infection along lymphatics with little focal suppuration. • From lymphatics infection can spread via blood stream
S. Agalactiae ·Viru| ence factor Capsule 阝 hemolysin GBS: The CaMP test is an important test for identification. It is characterized by the presence of group B Lancefield antigen and by its ability to hydrolyze sodium hippurate It is also sensitive to bile, and will lyse in its presence Causes Septicemia in newborns
S. Agalactiae • Virulence factor – Capsule – ß-hemolysin • GBS: The CAMP test is an important test for identification. It is characterized by the presence of group B Lancefield antigen and by its ability to hydrolyze sodium hippurate. • It is also sensitive to bile, and will lyse in its presence. • Causes Septicemia in newborns
Streptoccocus Agalactiae Pathogenesis Normal flora in gi tract, also can spread to the secondary site such as vagina in 10-30%women and large intestine Transferred to a neonate passing through the birth canal and can cause serious group B streptococcal infection S. Group B infection during the first month of life may present as fulminant sepsis, meningitis, or respiratory distress syndrome Neonatal pneumonia: S agalactiae invades via alveolar and pulmonary epithelial cells; newborns are especially susceptible to infection because they lack alveolar macrophages to prevent invasion
Streptoccocus Agalactiae Pathogenesis • Normal flora in GI tract, also can spread to the secondary site such as vagina in 10-30% women and large intestine • Transferred to a neonate passing through the birth canal and can cause serious group B streptococcal infection • S. Group B infection during the first month of life may present as fulminant sepsis, meningitis, or respiratory distress syndrome. • Neonatal pneumonia: S. agalactiae invades via alveolar and pulmonary epithelial cells; newborns are especially susceptible to infection because they lack alveolar macrophages to prevent invasion