Streptococcus pyogenes

Streptococcus pyogenes is a bacterium which belongs to group A beta hemolytic streptococci. Streptococcus pyogenes is one of the most important human pathogens. It is the most frequent bacterial cause of pharyngitis and a very common cause of skin infections. Many of the streptococcus pyogenes strains have a hyaluronic acid capsule that is antiphagocytic.

Transmission of Streptococcus pyogenes

Streptococcus pyogenes as many other streptococci is a part of the normal flora of the human throat and skin. But the number of streptococci pyogenes is small when compared to other streptococci.

Enzymes produced by streptococcus pyogenes

These enzymes are inflammatory mediators and important in the pathogenesis of different diseases.
1. hyaluronidase (spreading factor)
2. streptokinase (fibrinolysin)
3. DNase (streptodornase)

Toxins and hemolysins produced by streptococcus pyogenes
1. erythrogenic toxin
2. streptolysin O
3. streptolysin S
4. pyogenic extotoxin A
5. exotoxin B

Diseases caused by streptococcus pyogenes

1. pyogenic diseases (pharyngitis and cellulites)
2. toxigenic diseases (scarlet fever and toxic shock syndrome)
3. immunologic diseases (rheumatic fever and acute glomerulonephritis)

Laboratory tests for streptococcus pyogenes

1. microbiologic tests (gram stain)
2. serological tests (elevated ASO titer)

Treatment for streptococcus pyogenes infections

Fortunately almost all streptococcus pyogenes strains are susceptible to penicillin G, but neither rheumatic fever nor acute glomerulonephritis patients benefit from penicillin treatment after onset of the diseases.

Prevention of streptococcus pyogenes infections

1. treatment for pharyngitis to prevent rheumatic fever
2. hand washing