Nearly a century ago, a single colony of Staphylococcus aureus (S. aureus) helped launch the antibiotic age. In 1928, Alexander Fleming returned to his London lab to find that a stray mold had wiped out the Staphylococcus growing on one of his plates. The accident gave the world penicillin, ushering in the age of biomedicine and ensuring that an infected cut or scrape would not be fatal.