What role do hemolysins have in group A streptococcal (GAS) infections?

Updated: Sep 07, 2018
  • Author: Zartash Zafar Khan, MD, FACP; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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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.

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