Metabolite-mediated interactions and direct contact between Fusobacterium varium and Faecalibacterium prausnitzii.

Background: The human gut harbors a diverse microbiota that is crucial for maintaining health but also contributes to several diseases. Understanding how microbial communities are assembled and maintained is critical for advancing gut health.

Results: We identified a unique interaction between the pathobiont Fusobacterium varium and the symbiont Faecalibacterium prausnitzii, both members of the gut microbial community; their interaction is driven by metabolites and direct cell-to-cell contact. Growth of F. varium was inhibited in the presence of F. prausnitzii because of a decrease in pH and an increase in β-hydroxybutyric acid. Conversely, the growth of F. prausnitzii was promoted in the presence of F. varium, likely via direct contact.

Conclusions: These findings highlight the importance of metabolite-driven interactions and direct contact in shaping gut microbial communities and emphasize the potential of interactions between F. prausnitzii and F. varium in influencing gut health. Video Abstract.