<prompt> Streptococcal Toxic shock syndrome is due to the following virulence factor -M proteinPyrogenic exotoxinStreptolysin OCarbohydrate cell wall  <response>: Option 1 M protein: Mediates adherence to epithelial cells, inhibits phagocytosis Option 2 Streptococcal toxic shock syndrome By S. pyogenes M serotypes 1 or 3with hyaluronic acid capsule. Caused by SPE Streptococcal pyrogenic exotoxin or Erythrogenic toxin. 3 Types : Type A and C - Superantigens. Type A and C bacteriophage coded, B toxin chromosomal mediated. Associated with- Scarlet fever, Necrotizing fasciitis, Streptococcal toxic shock syndrome. Option 3 Streptolysin-O SL-O:- 1. Oxygen labile streptolysin-O , Heat labile 2. Antistreptolysin-O antibodies ASO are raised in most of the streptococcal infections and are used as a standard marker for retrospective diagnosis of streptococcal infections except in glomerulonephritis and pyoderma; where ASO titer is low. Option 4 Lancefields grouping for b haemolytic streptococci:- Based on carbohydrate antigen in cell wall, b haemolytic streptococci are fuher divided into 20 serogroups: Group A to V except I and J. 