The kiss of death: Limosilactobacillus reuteri PKS drives intraspecies competition.

The gut microbial ecosystem is governed by complex microbe-microbe interactions, with most documented as interspecies relationships. In this issue of Cell Host & Microbe, Özçam et al. identified intraspecies competition among related strains of the gut symbiont Limosilactobacillus reuteri that are mediated via the antimicrobial activity of polyketide synthase (PKS).