Enteropathogenic E. coli on human intestinal cells

The small red dots are enteropathogenic E. coli bacteria attaching to the surface of human intestinal cells in culture. During this process they sequester the actin (green) in the host cell to form actin-rich pedestals. This tends to give the appearance of a green halo around the bacteria. Once attached, the bacteria cause the tight junctions (blue) between the cells to break down, leading to the leakage of water into the intestine and consequent diarrhoea. Wellcome Image Awards 2008.