Knowing the make up the microbial community on the International Space Station (ISS) would be of huge use to space agencies trying to safeguard the wellbeing of their astronauts. This has been a focus of NASA's for a while, and its scientists have just put the finishing touches on what they say is the first comprehensive catalog of all the bacteria and fungi inside the ISS, describing a bacteria-filled environment not dissimilar to a gym or an office.

Over a period of 14 months, researchers gathered samples from eight different surfaces around the inside of the ISS, including viewing windows, toilets, exercise platforms and dining tables.

These surface samples were analyzed using traditional culture techniques and gene sequencing methods, and the results paint a picture of an enclosed environment brimming with bacteria. The microbes present on the ISS were found to be mostly linked to humans, with Staphylococcus aureus and Enterobacter among them.

These bacteria are rife in hospitals, offices, gyms and similar enclosed environments that are home to human activity. This is perhaps not all that surprising, given that 230 different people from 18 different countries have visited the ISS and it has been continuously occupied since 2000. But that doesn't make the research any less important, as scientists seek to better understand the microbes that inhabit these environments with a view to developing safety measures for missions to the Moon, Mars or maybe beyond.

"Specific microbes in indoor spaces on Earth have been shown to impact human health," says Dr Kasthuri Venkateswaran from NASA's Jet Propulsion Laboratory and author on the new study. "This is even more important for astronauts during spaceflight, as they have altered immunity and do not have access to the sophisticated medical interventions available on Earth. In light of possible future long-duration missions, it is important to identify the types of microorganisms that can accumulate in the unique, closed environments associated with spaceflight, how long they survive and their impact on human health and spacecraft infrastructure."

The team published its research in the journal Microbiome.