Bacteria. Eurgh. Microscopic bugs that we can’t live without. Icky as it is to contemplate (or amazing, if you’re one of those microbiology-fetishist sorts like Mr AllInTheGenes) the human body is home to bazillions of bacteria. That’s right, bazillions. On our skin, in our guts, in our mouths (eurgh eurgh), we wouldn’t function without these tiny troopers. The yoghurt adverts call these our ‘good’ bacteria. But for every Luke Skywalker there’s a Darth Vader — getting infected with ‘bad’ bacteria can cause food poisoning and meningitis and septicaemia and pneumonia and… you get the picture. What’s more, even the good bacteria can turn against us, Anakin Skywalker style, if they find themselves in the wrong part of the body, or if something happens that gives them an advantage over their neighbours. At the moment, we combat unwanted bacteria with antibiotics: compounds that stop the bugs from functioning properly. But as you are probably aware, a crisis is looming. The drugs have stopped working.