Question

What advantage could hemolysins give to Streptococcus pyogenes?

Answer 1

Hemolysins are a group of exotoxins produced by some bacteria. They cause the lysis of RBC by disrupting their cell membrane.

Streptococcus pyogenes is Gram +ve bacteria that produce hemolysins. When these bacteria are grown on the blood agar plate, they produce small zones of beta-hemolysis. These toxins provide a selective advantage to the bacteria in the host system.

Streptolysin O is an exotoxin produced by Streptococcus pyogenes. It is the major factor responsible for beta-hemolytic activity. It is also responsible for the initiation of the host immune response and detection of the host antibodies. Antistreptolysin O is generally used as a clinical marker to confirm a recent infection.

Streptolysin A is a cardiotoxic exotoxin produced by Streptococcus pyogenes. It is a strong cell poison that affects many host cells such as neutrophils, platelets.