Staphylococcus aureus produces a golden carotenoid virulence factor called staphyloxanthin (STX), and we report here the inhibition of the enzyme, dehydrosqualene synthase (CrtM), responsible for the first committed step in STX biosynthesis. The most active compounds are halogen-substituted phosphonosulfonates, with K i values as low as 5 nM against the enzyme and IC50 values for STX inhibition in S. aureus as low as 11 nM. ...