Coloured scanning electron micrograph (SEM) of Photocomposite,E.coli on surface of human skin.Escherichia coli is Gram-negative,facultatively anaerobic,enteric,rod prokaryote.This bacterium is normally part of human animal microbiota.Most E.coli strains are harmless,but some strains can cause serious problems such as: food poisoning,urinary tract infections,traveller's diarrhoea nosocomial infections.The E.coli 0157:H7 strain is fatal to humans if contracted when contaminated meat is cooked inadequately.Magnification: bacteria x800; skin x6 when shortest axis printed at 25 millimetres. Stock Photo