With resistance to antibiotics on the rise, alternative therapeutic strategies to treat infectious diseases, such as anti virulence approaches, are urgently needed. Curtis et al. developed a broad-spectrum inhibitor (LED209) of the membrane-bound histidine kinase QseC, which is conserved in several Gram-negative pathogens and promotes the expression of key virulence genes. The authors showed that LED209 is highly selective and reduces the virulence of several multidrug-resistant pathogens in vitro and in infected mice. The compound has a unique mode of action by acting as a prodrug scaffold to deliver a 'warhead' that allosterically inhibits QseC signalling to decrease virulence gene expression. The authors also found that pre-treatment of mice with LED209 conferred low-level protection against bacterial infection.