Ever had an upset tummy? It might have looked a bit like this – at least, on a microscopic level. These unsuspecting human cells (artificially coloured orange) are about to be invaded by Shigella bacteria, painted in pink. They're related to the food poisoning bacteria Salmonella, and are responsible for causing severe diarrhoea and dysentery. While antibiotics can be effective treatments, some types of Shigella have become resistant, and it's a growing problem. When the germs get into the body – for example through the gut – one end of each rod-shaped bug latches onto the cell surface, where it injects a chemical that makes the cell swallow it whole. From there, the bacteria move onwards, infecting more cells and causing illness. Researchers are trying to understand exactly how Shigella sticks to our cells, with the aim of finding more effective ways to stop these nasty bugs in their tracks.
Written by Kat Arney
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.