<prompt> Surface antigen of E coli acting as virulence factors are:-LPS O AntigenCapsular K antigenFimbriaeAll of the above  <response>: Virulence factors of E. coli: Surface antigens Toxins Somatic or O ag- Lipopolysaccharide LPS, most impoant virulence factor responsible for endotoxic activities LT heat labile toxin - - cAMP so causes excessive secretion of NaClH2O from within to outside the cell secretory diarrhea Flagellar or H Ag- Makes the bacteria motile. ST heat stable toxin- - cGMP so fluid accumulation in gut Diarrhea Capsular or K Ag- It is a polysaccharide capsular Ag, inhibits the phagocytosis. Verocytotoxin or Shiga like toxin - - It inhibits the protein synthesis by binding to 28S subunit of 60S ribosome Cell death Fimbrial antigen Pilus - helps in attachment colonization. 