The microbial community composition on the International Space Station (ISS) is more similar to home surfaces than to the human microbiome samples, according to a new study published in the journal PeerJ.
The International Space Station. Image credit: NASA.
A team of microbiologists from the University of California, Davis, and elsewhere analyzed swabs taken by astronauts on 15 locations on the ISS.
“The ISS sampling involved the collection and microbial analysis of 15 surfaces sampled by swabs onboard the ISS, and was a component of Project MERCCURI (Microbial Ecology Research Combining Citizen and University Researchers on ISS),” the scientists said.
“Swabbing was conducted during Expedition 39. The crew included NASA astronauts Steve Swanson and Rick Mastracchio; cosmonauts Oleg Artemyev, Alexander Skvortsov, and Mikhail Tyurin. JAXA astronaut Koichi Wakata was the commander for this expedition, and is the astronaut who performed the swabbing.”
The most common bacterial families found on the ISS surfaces were human-associated: Actinomycetales – 18.3% (dominant genus – Corynebacterium), Bacillales – 14% (Staphylococcus), Bacteroidales – 12.8%, Lactobacillales – 11.1% (Streptococcus), Clostridiales – 11% (Finegoldia), and Pseudomonadales – 6.1% (Pseudomonas).
“Since the ISS is completely enclosed, the microbes inside the station come from the people on the ISS and the supplies sent to them,” said Dr. David Coil, co-author of the study.
Dr. Coil and colleagues compared their data on the species to published data sets from two other projects: the Wildlife of Our Homes study, which evaluated home microbiomes, and surveys of human body sites from the Human Microbiome Project.
They found that the bacterial community on the ISS was very diverse and more closely resembled that of homes than of humans.
“The microbiome on the surfaces on the ISS looks very much like the surfaces of its inhabitants, which is not surprising, given that they are the primary source,” said Dr. Jenna Lang, lead author of the study.
“We were also pleased to see is that the diversity was fairly high, indicating that it did not look like a ‘sick’ microbial community.”
“Studying the microbial diversity on the ISS is not only of relevance to space exploration but also serves as an important comparison to buildings on Earth because the ISS has many novel features such as limited influx of microbes,” said senior author Professor Jonathan Eisen.
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J.M. Lang et al. 2017. A microbial survey of the International Space Station (ISS). PeerJ 5: e4029; doi: 10.7717/peerj.4029
