The discovery of antibiotics more than 80 years ago has led to considerable improvements in human and animal health. Although antibiotic resistance in bacteria is ancient, resistance in human pathogens is thought to be a modern phenomenon that is driven by the clinical use of antibiotics. A new study shows that particular lineages of Staphylococcus aureus developed resistance to the antibiotic methicillin around 200 years ago. This SEM image depicts...