Telomere bacteriophages are widespread and equip their bacterial hosts with potent interbacterial weapons (Science Advances 2025)

Byers et al. report that telomere phages, which replicate their genomes as linear extrachromosomal elements, are widely distributed in bacteria and highly prevalent in Klebsiella species. In phage-host cells only a small set of phage proteins is expressed, including a toxin, the telocin, that kills other Klebsiella strains; the authors discuss using telocins for precision editing of microbial populations.