Gestational dysbiosis is associated with altered early-life microbial seeding and favors pathobiont expansion in offspring

Maternal gut microbiota shape early-life microbial community assembly, yet how maternal dysbiosis alters microbial inheritance remains poorly defined. Here, we investigated whether antibiotic-induced maternal dysbiosis affects microbial patterns in offspring using a gestational vancomycin mouse model. 16S rRNA profiling revealed that dysbiotic dams exhibited reduced microbial richness and evenness, with the enrichment of pathobionts including Enterococcus faecium and Cronobacter muytjensii . Offspring of dysbiotic dams displayed distinct microbial community structures, lower diversity, and reduced similarity to their mothers (21.5%) compared with controls (61%). Notably, maternal dysbiosis was associated with the enrichment of Gammaproteobacteria pathobionts in offspring, whereas control dyads were characterized by commensal Bacteroidia and Clostridia . These findings indicate that maternal dysbiosis during pregnancy is associated with altered maternal-offspring microbial similarity and shifts in early-life microbial community composition.