Streptolysin

Definition

Streptolysin is a type of exotoxin produced by Streptococcus bacteria, particularly Group A Streptococcus. It plays a significant role in the pathogenesis of various respiratory infections.

5 Must Know Facts For Your Next Test

1. Streptolysin O is oxygen-labile and can be inactivated by oxygen, while Streptolysin S is oxygen-stable.
2. Streptolysin O is antigenic and induces an immune response, allowing for the detection of anti-streptolysin O (ASO) antibodies as a diagnostic marker.
3. Streptolysins contribute to tissue damage by lysing red blood cells, white blood cells, and platelets.
4. The presence of streptolysins enhances the virulence of Streptococcus pyogenes, leading to diseases such as pharyngitis and scarlet fever.
5. Both types of streptolysins can cause beta-hemolysis when cultured on blood agar plates.

Review Questions

• What are the differences between Streptolysin O and Streptolysin S?
• How do streptolysins contribute to the pathogenicity of Group A Streptococcus?
• Why is anti-streptolysin O (ASO) titer important in diagnosing certain infections?

Related terms

Exotoxin: A toxin released by bacteria into their surroundings that causes damage to host tissues.

Beta-Hemolysis: The complete lysis of red blood cells around a bacterial colony on blood agar, often associated with streptococcal species.

Group A Streptococcus (GAS): A category of streptococci that includes Streptococcus pyogenes, known for causing numerous infections including pharyngitis and skin infections.