Escherichia coli (Gram-negative) is the predominant facultative organism in the human intestine. It is responsible for a number of diseases like urinary tract infections, gastroenteritis (diarrhoea), meningitis, traveler's diarrhea and hemorrhagic colitis. There are a myriad of serotypes of pathogenic E. coli. Adhesion to the host cells is an important step in its pathogenesis. However, most strains are harmless and normal flora residing in the gut.
