Mushroom β-Glucan as a Novel Prebiotic: Enhancing Recovery of the Post-Antibiotic Gut Microbiota over 60 Days

Antibiotic-induced dysbiosis can cause persistent alterations in gut microbial composition and fermentative metabolism, yet the long-term role of mushroom β-glucan-based prebiotics in supporting post-antibiotic microbiota modulation remains poorly defined. To address this gap, the present study evaluated the modulatory effects of ColonX, a mushroom β-glucan-based formulation, during a 60-day in vitro simulation of post-antibiotic gut microbiota modulation. Quantitative PCR (qPCR) was used to monitor key bacterial groups, while UHPLC-DAD analysis was applied to characterize fermentation-derived organic acids. ColonX administration produced a selective, time-dependent increase in Bifidobacterium spp., with limited effects on Lactobacillus spp. and no stimulation of opportunistic bacteria such as Escherichia coli. This response became more evident after prolonged administration, suggesting progressive adaptation of the dysbiotic microbiota. Metabolomic analysis showed increased production of short-chain fatty acids and other fermentation-derived organic acids, indicating enhanced saccharolytic activity and functional metabolic remodeling. The accumulation of succinic acid further suggested ongoing microbial metabolic restructuring during recovery, while comparison with individual excipients indicated that resistant dextrin contributed to the fermentative response. Overall, this study addresses an important gap by linking prolonged mushroom β-glucan administration with both taxonomic modulation and functional metabolic recovery markers in a post-antibiotic dysbiosis model. These findings support ColonX as a promising nutraceutical strategy to promote gut microbiota restoration following antibiotic exposure.