Human symbionts inject and neutralize antibacterial toxins to persist in the gut

Significance The microbial community in the human gut represents one of the densest known ecosystems. Community composition has broad impacts on health, and metabolic competition and host selection have both been implicated in shaping these communities. Here, we report that contact-dependent bacterial antagonism also determines the ability of human gut symbionts to persist in the microbiome. Simplified microbiomes, assembled in gnotobiotic mice, reveal effector transmission rates exceeding 1 billion events per minute per gram of colonic contents. Together, these results suggest that human gut symbionts define their closest competitors not only metabolically but also spatially. Moreover, strains within a single species can encode diverse effectors that may provide new avenues for shaping the microbiome to improve human health.

Human symbionts inject and neutralize antibacterial toxins to persist in the gut Journal Articles