Cross-feeding-based rational design of a probiotic combination of Bacterides xylanisolvens and Clostridium butyricum therapy for metabolic diseases

The human gut microbiota has gained interest as an environmental factor that contributes to health or disease. The development of next-generation live biotherapeutic products (LBPs) is a promising strategy to modulate the gut microbiota and improve human health. In this study, we identified a novel cross-feeding interaction between Bacteroides xylanisolvens and Clostridium butyricum and developed their combination into a novel LBP for treating metabolic syndrome. Using in-silico analysis and in vitro experiments, we demonstrated that B. xylanisolvens supported the growth and butyrate production of C. butyricum by supplying folate, while C. butyricum reciprocated by providing pABA for folate biosynthesis. Animal gavage experiments showed that the two-strain combination LBP exhibited superior therapeutic efficacy against metabolic disorders in high-fat diet-induced obese (DIO) mice compared to either single-strain treatment. Further omics-based analyses revealed that the single-strain treatments exhibited distinct taxonomic preferences in modulating the gut microbiota, whereas the combination LBP achieved more balanced modulation to preserve taxonomic diversity to a greater extent, thereby enhancing the stability and resilience of the gut microbiome. Moreover, the two-strain combinations more effectively restored gut microbial functions by reducing disease-associated pathways and opportunistic pathogen abundance. This work demonstrates the development of new LBP therapy for metabolic diseases from cross-feeding microbial pairs which exerted better self-stability and robust efficacy in complex intestinal environments compared to conventional single-strain LBPs.