Investigation of Spaceflight-Induced Changes to Astronaut Microbiomes

Disruptions in the human microbiome due to exposure to space could potentially cause illness in astronauts that may be difficult to treat. To evaluate the effects of spaceflight on the human microbiome, body swabs and saliva samples were collected from four ISS astronauts on consecutive expeditions. Samples were analyzed to characterize the microbial biodiversity before, during, and after the astronauts’ time onboard the International Space Station (ISS).  

There were some changes in each astronaut’s microbiome during spaceflight, but these changes were not universal for all four astronauts. Two antimicrobial resistance gene markers did show a significant change in abundance in the saliva samples of all four astronauts across their collection times. This study was the first to successfully use genetic techniques (metagenome sequencing and microarrays) to identify microbes in the various sampling locations from the astronauts. 

Results from this study provide insight for future ISS microbial monitoring studies and targets for antimicrobial resistance screenings. The goal of the study was to characterize astronaut’s microbiome changes due to spaceflight conditions and identify any changes that may pose health risks to the astronauts during their mission. Tracking the entire crew could help identify the changes that are introduced from crew interactions, which will enable better characterization of the microbiome variations due to the environmental stresses of spaceflight. The article is available online here.