• GM+
• Streptococcus
  • Fastiduous
  • Nutrients
  • Sensitive to drying, heat, desinfectants
• Most serious strep pathogen
• Classified as Group A

What are the three groups of Streptococcus pyogenes virulence factors?

1. Enzymes
2. Exotoxins
3. Cell Bound

• Streptolysis - lysis RBC (Cause Blood Agar reaction - Beta Hemolysis)
• Erythorogenic Toxin - causes scarlet fever, red rash

• M Protein - fuzzy surface on MO, increases adherance and is antiphagocytic
• Hyaluronic Acid Capsule - antiphagocytic capsule

• Streptokinase - dissolves blood clots
• Hyaluronidase - spreading factor
• DNase

What are the carriers of Streptococcus pyogenes?

• Humans are resevoirs - 5-15%
• Strict parasite of the throat

• Direct contact
• Respiratory droplet

• Weakend IS
• Children ages 5-15

• Skin infections
• Mucous Membrane infections
• Systemic infections
• Long-term complications

1. Impetigo
   • Enters through nick in skin
   • Burning, itching papules
   • Contagious yellow crust
2. Erysipelas
   • Enters through wound
   • Spreads rapidly
   • Edema, fever, can be lethal
3. Cellulitis

• Streptococcal Pharyngitis - strep throat
• Tonsillitis
• Sinusitis
• Otitis Media

• Scarlet Fever - caused by erythrogenic toxin
  • High fever with red rash
• Septicemia - infection of lympatics and blood

• Few weeks after primary infection
• Rheumatic Fever (RF) - delayed inflammatory condition of joints and heart
• Acute Glomerulonephritis (AGN) - Type III hypersentivity, Ag-Ab complexes deposit in kidneys.
  • Increases blood pressure, heart failur

• Phagocytosis
• Antibodies for M protein, erythrogenic toxin, streptolysis

• Rapid Ab test for gropu A, C-carbohydrate
• Blood Agar Plate (BAP) - beta hemolysis

• Penicillin or derivitive
• RF or AGN - no treatment, treat and prevent primary infection