Examination into the HI-SEAS IV crew member microbiome reveals potential role of preferred interactions on skin microbial community structure

Astronauts experiencing prolonged space travel report increased skin hypersensitivity and delayed wound healing as a result of changes to the skin microbiome during space travel. In this study, we explored the effects of close social relationships within isolated built environments on the human skin microbiome. We analyzed the effect of crew interactions on the microbiome dynamics of six astronauts using a dataset from a year long Earth-bound Mars simulation called the Hawaii Space Exploration Analog and Simulation IV (HI-SEAS IV) mission. Microbial profiles were processed by Mahnert et al. based on amplicons targeting the V4 region of the 16S rRNA gene. We performed alpha and beta diversity longitudinal volatility analysis, taxonomic classifications, PCoA analysis, differential abundance analysis, and designed Venn diagrams to determine changes in microbiome dynamics. Within the dataset, we found that crew member pairs appeared to trend towards similar skin microbiomes, and microbiomes within pairs were found to be significantly more similar than between pairs. Furthermore, we found that the taxonomic composition of crew member skin microbiomes changed significantly between final and initial time points of the year-long mission. Our results suggest a potential for close physical interactions to modulate human skin microbiomes within isolated environments, and highlight the necessity for further examinations into the impact of such interactions on skin health.