Answer
S pyogenes elaborates 2 distinct hemolysins. These proteins are responsible for the zone of hemolysis observed on blood agar plates and are also important in the pathogenesis of tissue damage in the infected host. Streptolysin O is toxic to a wide variety of cell types, including myocardium, and is highly immunogenic. The determination of the antibody responses to this protein (antistreptolysin O [ASO] titer) is often useful in the serodiagnosis of recent infection.
Streptolysin S is another virulence factor capable of damaging polymorphonuclear leukocytes and subcellular organelles. However, in contrast to streptolysin O, it does not appear to be immunogenic.
Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!
Media Gallery
-
Invasive soft tissue infection due to Streptococcus pyogenes. This child developed fever and soft-tissue swelling on the fifth day of a varicella-zoster infection. Leading edge aspirate of cellulitis grew S pyogenes. Although the patient responded to intravenous penicillin and clindamycin, operative débridement was necessary because of clinical suspicion of early necrotizing fasciitis.
-
Streptococcus group A infections. Beta hemolysis is demonstrated on blood agar media.
-
Streptococcus group A infections. M protein.
-
Streptococcus group A infections. Erysipelas is a group A streptococcal infection of skin and subcutaneous tissue.
-
Streptococcus group A infections. White strawberry tongue observed in streptococcal pharyngitis. Image courtesy of J. Bashera.
-
Streptococcus group A infections. Streptococcal rash. Image courtesy of J. Bashera.
-
Group A Streptococcus on Gram stain of blood isolated from a patient who developed toxic shock syndrome.
-
Streptococcus group A infections. Necrotizing fasciitis of the left hand in a patient who had severe pain in the affected area.
-
Streptococcus group A infections. Patient who had had necrotizing fasciitis of the left hand and severe pain in the affected area (from Image 8). This photo was taken at a later date, and the wound is healing. The patient required skin grafting.
-
Streptococcus group A infections. Gangrenous streptococcal cellulitis in a patient with diabetes.
-
Erythema secondary to group A streptococcal cellulitis.
-
Invasive soft tissue infection due to Streptococcus pyogenes. This child developed fever and soft-tissue swelling on the fifth day of a varicella-zoster infection. Leading edge aspirate of cellulitis grew S pyogenes. Although the patient responded to intravenous penicillin and clindamycin, operative débridement was necessary because of clinical suspicion of early necrotizing fasciitis.
-
Streptococcus group A infections. Necrotizing fasciitis rapidly progresses from erythema to bullae formation and necrosis of skin and subcutaneous tissue.
-
Throat swab. Video courtesy of Therese Canares, MD; Marleny Franco, MD; and Jonathan Valente, MD (Rhode Island Hospital, Brown University).
of
14