S2148 Assessing Seasonal Variations in Gut Microbiome Composition: A Comparative Study of Summer and Winter Profiles

Introduction: This study investigated seasonal variations in gut microbiome composition and diversity, emphasizing the potential impact of environmental and dietary changes. Methods: Stool samples were collected from 21 participants in summer and in wintertime. Microbial DNA sequencing from the stool samples were analyzed. Gut microbiome relative abundances of 14 bacterial genera and alpha diversity metrics were measured to evaluate seasonal differences. Results: Significant variations were observed in microbial composition. Bifidobacterium exhibited variability between summer and winter exceeding 70%, reflecting sensitivity to seasonal factors, while Bacteroides demonstrated shifts of over 30%, indicating dynamic responses to seasonal influences. Prevotella abundance decreased by more than 40% in several cases, and Phocaeicola showed changes nearing 35%, underscoring their responsiveness to environmental shifts. The Shannon Diversity Index revealed higher microbial diversity in summer (mean = 3.64, SD = 0.53) compared to winter (mean = 3.39, SD = 0.75), indicating greater richness and evenness during warmer months. Conclusion: These findings highlighted the gut microbiome's dynamic adaptability to seasonal changes, providing insights into the interplay between environmental factors and microbial diversity. Further larger studies are needed to assess and confirm a microbiome signature for winter and summer, given that a lower diversity in winter months may be linked to a weaker immune system, and thus susceptibility to colds, flus and other respiratory illnesses and infections.