Overview
Escherichia coli is a Gram-negative, facultatively anaerobic rod that is part of the normal gut flora. It does not usually cause disease, but some strains can cause diarrhoea, urinary tract infections, meningitis in the neonates, and haemolytic uraemic syndrome depending on the toxins they produce and antigens they express.
Since it does not normally exist outside of the body, its presence in food or water can suggest faecal contamination.
