LAUSR

Antimicrobials Clostridium difficile infects hundreds of thousands of people each year and is becoming increasingly tough to treat. Kirk et al. studied a C. difficile –specific antimicrobial derived from a genetically modified bacteriocin. They isolated strains resistant to the treatment, which were found to have mutations in the surface layer of the cell envelope. The mutants had attenuated virulence but were still able to colonize the gut of hamsters. These findings showcase how making targeted antimicrobials can force bacteria to sacrifice virulence in favor of survival. Sci. Transl. Med. 9 , eaah6813 (2017).