E. coli O111 bacteria. Coloured transmission electron micrograph (TEM) of a section through Escherichia coli O111 bacteria. These are enterohaemorrhagic E. coli (EHEC), a dangerous form of the normally harmless E. coli bacteria which live in the human intestine. Usually transmitted though contaminated food, they can cause life-threatening diarrhoea, intestinal bleeding, kidney failure and disturbances to blood clotting. There are no effective cures for EHEC, but there are treatments for dealing with the symptoms of infection. Another strain of EHEC bacteria is E. coli O157:H7. Magnification: x47,000 at 6x7cm size. Magnification: x160,000 at 8x10 size."