A multi-strain biofilm consortium enhances gut microbiota resilience and restores post-antibiotic homeostasis.

Antibiotics can significantly disrupt gut microbiota homeostasis, reducing microbial diversity and causing dysbiosis associated with health issues. Gut biofilms play a critical role in resilience and stress tolerance of the intestinal ecosystem. Mucosal microbial communities also help restore the gut microbiota after interventions like probiotics, antibiotics, or fecal transplants. Previously, we developed a core bacterial consortium with strong in vitro biofilm-forming and stress-resilient properties, but its colonization ability and in vivo function remained unclear. In this study, we first validated the in vivo biofilm formation of the microbial consortium using a germ-free (GF) mouse model, then introduced single-, dual-, and multi-strain combinations with varying biofilm-forming abilities into specific-pathogen-free mice to assess their potential for recovering antibiotic-disrupted gut microbiota. Our findings indicate that the robust, in vitro-selected consortium continued to form substantial biofilms in GF mouse intestines. 16 S rRNA sequencing showed that, compared to single- or dual-strain treatments, administering the core consortium significantly increased microbial richness and diversity. The gut microbiota of consortium-treated mice more closely resembled healthy controls, suggesting the core consortium has superior potential to restore healthy gut microbiota. Overall, our research demonstrates the core consortium markedly improves gut microbiota resilience to antibiotic-induced disruptions in mice, accelerates restoration of health-associated taxa, and reestablishes gut homeostasis. This approach could transform probiotic interventions from passive supplementation to active ecological engineering, providing a theoretical and experimental basis for next generation of engineered probiotics and microbiome restoration therapies.