Abdominal cramps, diarrhoea, slimy and bloody stools, fever, dehydration, and maybe even death – these are the horrid symptoms of a Shigella infection, one of the most common foodborne bacterial illnesses. The bacteria (shown coloured blue) are passed between humans by the faecal-oral route, which is a nice way of saying that tiny poo particles containing the bacteria end up in a person’s mouth. Ugh. Once inside the human intestine, the bugs attach to epithelial cells and are absorbed into the cells in membrane-bound packages called vacuoles. Ordinarily, such vacuoles would be transported to the cell’s waste disposal units – lysosomes – for degradation. But, scientists have found Shigella subverts the process recruiting specialised vesicles (green) of the host cell to help rupture the vacuole. Free from constraint, the bacteria can replicate abundantly and ultimately destroy the cell, sending vast numbers of the bacteria out of the gut in the next grisly defaecation.
Written by Ruth Williams
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