Significance of Changes in the Skin Fungal Microbiomes of Astronauts Staying on the International Space Station

A wide variety of microorganisms colonize the human skin and are important to maintaining human health. However, this community is highly sensitive to perturbations, and diseases can develop when the skin microbiome is disrupted by a change in host or environmental conditions. The International Space Station (ISS) is a closed environment, and astronauts on the ISS do not wash their bodies as frequently as when they are on the ground. The maintenance of a balanced skin microbiome is important to overall health, disease prevention, and a high quality of life while on the ISS. The skin fungal microbiome is dominated by Malassezia sp. These lipophilic fungi are ubiquitous across different skin types, whereas changes in the levels of M. globosa and M. restricta are correlated with the formation of seborreich dermatitis/dandruff. The Malassezia microbiome on the skin of astronauts staying on the ISS changed, and there was a reduction in skin fungal microbial diversity. These findings provide useful information about temporal changes in the hygiene of astronauts who are on the ISS for an extended period and indicate that Malassezia microbiome as microbiological markers of skin hygiene.