The rise of antibiotic resistance has researchers searching for new targets in pathogenic bacteria. One promising target is an enzyme called DXR that is essential for isoprenoid synthesis in most bacteria. DXR is inhibited by the antibiotic fosmidomycin, which is used to treat multidrug-resistant bacteria and the malaria parasite. However, a few pathogenic bacteria do not have DXR but have an unrelated enzyme called DRL instead.