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, especially in China, from using large quantities of colistin to fatten up pigs and chickens.
Now Yi-Yun Liu at the South China Agricultural University in Guangzhou and colleagues have discovered the first known resistance gene for colistin that is able to move freely from one bacterium to another.