Important Complexities of the Antivirulence Target Paradigm: A Novel Ostensibly Resistance-Avoiding Approach for Treating Infections.

Use of antivirulence therapy has assumed that inhibition of bacterial fitness at the site of infection without directly affecting viability will minimize the development of resistance. However, selection for resistant strains is much more likely to occur at sites of colonization or in the environment following excretion of the therapeutic agent. Data are needed regarding whether the drug's target promotes fitness among bacteria in (drug-exposed) niches other than sites of infection. Furthermore, in vivo studies of resistance selection should assess off-target selection for resistance (eg, within the microbiome). Only when such data are available can the risk for development of resistance be gauged appropriately.