Resistance genes identified in China suggests we could soon see bacteria that are resistant to every known type of antibiotic, and these genes have already been found in bacteria infecting people. Until now, a type of bacteria known as Gram negative have remained susceptible to one particular class of antibiotics, called polymyxins. These have become known as “last resort” antibiotics, increasingly used to treat infections that resist every other kind. In 2012, the World Health Organisation classified colistin, the most widely used polymyxin, as being critically important for human health. But that didn’t stop farmers around the world, from using large quantities of colistin to fatten up pigs and chickens.