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

Abstract 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.