Environmental exposures influence nasal microbiome composition in a longitudinal study of division I collegiate athletes

Background: The anterior nares host a complex microbial community that contributes to upper airway health. Although the bacterial composition of the nasal passages have been well characterized in healthy and diseased cohorts, the role of prolonged environmental exposures and exercise in shaping the nasal microbiome in healthy adults is poorly understood. In this study, we longitudinally sampled female collegiate Division I athletes from two teams experiencing a similar athletic season and exercise regimen but vastly different environmental exposures (Swim/Dive and Basketball). Using 16S rRNA gene sequencing, we evaluated the longitudinal dynamics of the nasal microbiome pre-, during-, and at the end of the athletic season. Results: The nasal microbiota of the Swim/Dive and Basketball teams were distinct from each other at each time point sampled, driven by either low abundance (Jaccard, PERMANOVA p<0.05) or high-abundance changes in composition (Bray-Curtis, PERMANOVA p<0.05). The rate of change of microbial communities were greater in the Swim/Dive team compared to the Basketball team characterized by an increase in Staphylococcus in Swim/Dive and a decrease in Corynebacterium in both teams over time. Conclusions: This is the first study that has evaluated the nasal microbiome in athletes. We obtained longitudinal nasal swabs from two gender-matched teams with similar age distributions (18-22 years old) over a 6 month period. Differences in the microbiota between teams and over time indicate that chlorine exposure, and potentially athletic training, induced changes in the nasal microbiome.