Virulence of Group Aβ-hemolytic streptococci(S. Pyogenes) Structural compositions of GAs Hyaluronic Acid Capsule Mprotein Lipoteichoic acid (LTA) Fibronectin-binding protein (F protein) Secretion products of GAs Erythrogenic toxins (Pyogenic exotoxins)Hemolysin O, Hemolysin S (SLO & SLS)口 HyaluronidaseStreptokinase (SK)口 Streptodornase (SD)21DIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY
Virulence of Group A β – hemolytic streptococci (S. Pyogenes) □ S t r u c t u r a l c o m p o s i t i o n s of GAS □ Hyaluronic Acid Capsule □ M protein □ Lipoteichoic acid (LTA) □ Fibronectin-binding protein (F protein) □ S e c r e t i o n p r o d u c t s of GAS □ Erythrogenic toxins (Pyogenic exotoxins) □ Hemolysin O, Hemolysin S (SLO & SLS) □ Hyaluronidase □ Streptokinase (SK) □ Streptodornase (SD) 21 DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY
大Virulence ofGASErythrogenictoxins (Pyogenic exotoxins) There are threeantigenically distincterythrogenic toxins: type A, B and C. Erythrogenic toxins are responsible for therash,fever and pus formation ofscarlet fever. Erythrogenic toxins are super-antigens and result ingeneration of inflammatory cytokines which areresponsible for streptococcus toxic shock- likesyndrome (STSS).Antibody against erythrogenic toxins can prevent口development of rash but do not protect theunderlying infection.DIVISION OFINFECTIOUS DISEASE AND GASTROENTEROLOGY
E r yt h r o g e n i c t o x i n s ( P yo g e n i c e x o t o x i n s ) □ There are three antigenically distinct erythrogenic toxins: type A, B a n d C. □ Erythrogenic toxins are responsible for the rash, fever a n d pus formation of scarlet fever. □ Erythrogenic toxins are super-antigens a n d result in generation of inflammatory cytokines which are responsible for strep tococcu s toxic shock- like syn d rome (STSS). □ Antibody against erythrogenic toxins ca n prevent develop ment of ra sh but d o not protect the underlying infection. DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY Virulence of GAS
?VirulenceofGAsHemolysinOHemolysin O(Streptolysin O) can lyse red blood cells口and it is toxic to neutrophils, platelets and heart muscleAntibody against Streptolysin O (AsO) is diagnostic for口recent GAS infection.Hemolysin SHemolysin S damages the membranes of neutrophils and口platelets.Hemolysin O and S areresponsiblefortheclearzoneofhemolysis permitting classification of the organisms asβ- hemolytic strains.DIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY
H e m o l ys i n O □ Hemolysin O(Streptolysin O) can lyse red blood cells and it is toxic to neutrophils, platelets and heart muscle. □ Antibody against Streptolysin O (ASO) is diagnostic for recent GAS infection. H e m o l ys i n S □ Hemolysin S damages the membr anes of neutrophils and platelets. Hemolysin O a n d S are responsible for the clear zone of hemolysis permitting classification of the orga n is ms a s β- hemolytic strains. DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY Virulence of GAS
?VirulenceofGAsHyaluronidase (the original "spreading factor")can digest hyaluronic acid of host connectivetissue.Streptokinases(SK) participate in fibrinlysis,stopthe coagulation of blood and facilitate rapidspreading of streptococci through tissues.Streptodornases(SD,DNase)A-Dpossessdeoxyribonuclease activity; Streptodornases BandDpossess ribonuclease activity as well, helpsliquefy pus.DIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY
Hyaluronidase (the original "spreading factor") can digest hyaluronic acid of host connective tissue. Streptokinases(SK) participate in fibrin lysis, stop the coagulation of blood and facilitate rapid spreading of streptococci through tissues. S tr eptodornases (SD, DNase) A-D possess deoxyribonuclease activity; Streptodornases B and D possess ribonuclease activity as well, helps liquefy pus. DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY Virulence of GAS
?Virulence ofGASAdherence (colonization)Mprotein, LTA, Protein FEnhancement of spread intissuesHyaluronidase, SK, SDEvasion of phagocytosisHyaluronic acid, MproteinInvasinsSK, SD, Hyaluronidase, andHemolysinsErythogenic toxins (Pyrogenic Exotoxins)Fever, rash, STSsDIVISION OFINFECTIOUS DISEASE ANDGASTROENTEROLOGY
Adherence (colonization) M protein, LTA, Protein F Enhancement of sp r ead in tissues Hyaluronidase, SK, SD Evasion of phagocytosis Hyaluronic acid, Mprotein Invasins SK, SD, Hyaluronidase, a n d Hemolysins Erythogenic toxins (Pyrogenic Exotoxins) Fever, rash, STSS DIVISION O F INFECTIO US DISEAS E AND GASTRO ENT E RO LO GY Virulence of GAS