Despite orbiting 248 miles above the Earth, the International Space Station is swarming with infectious germs, a new study has found – and astronauts might have to get the vacuum cleaner out if they want to avoid inflammation or skin irritations.
While the opportunistic bacterial pathogens are mostly innocuous on Earth, they are thriving in the station that has turned out to be a prime breeding ground.
It seems the bugs like their new home in the unique environment that has experienced microgravity, space radiation, elevated carbon dioxide and continuous occupation by humans for nearly 15 years.
An analysis of dust collected from the artificial satellite found thatActinobacteria – a type of bacteria associated with human skin – made up a larger proportion of the microbial community in the ISS.
Two groups of opportunistic pathogens that can lead to infections were also found in the ISS dust samples, but the research did not address the virulence of these pathogens in closed environments or the risk of infection to astronauts.
Understanding the nature of the communities of microbes – the microbiome – in the station is key to managing astronaut health and maintenance of equipment, senior research scientist Dr Kasthuri Venkateswaran said.
Traditionally, culture bacteria and fungi in the lab had been used to assess the composition of this community.
NASA scientists from its Jet Propulsion Laboratory used the latest DNA sequencing technologies to rapidly and precisely identify the micro organisms present on the ISS, filling in the gaps left by traditional methods, and highlighting pathogens that may pose a threat to astronauts.
They collected air filter samples and vacuum bag dust from the ISS and compared it to “clean rooms” – sterile rooms with airlocks to reduce contamination of equipment sent into space – on Earth.
But while clean rooms circulate fresh air, air is filtered and recirculated on board the station. It is inhabited continuously by only six people, while 50 people may be in clean rooms in a day, but not inhabit them continuously.
The study published in the journal Microbiome analysed the samples for micro organisms and then stained their cells with a dye to determine whether they were living or dead.