Space bacteria floating above Earth is mutating to survive, scientists say

Microbes stuck in the International Space Station are adapting to survive in the harsh environment of space, scientists say.

A new study sheds light on how the bacteria floating above Earth is changing as a result of its difficult environment.

And it found it is not mutating into especially dangerous or antibiotic-resistant superbugs that humans could not kill. Instead, it is just changing to deal with the difficulties of floating above Earth, they said.

That could be helpful because of the scientists who could have to spend years in space with the bacteria as they fly deep into space on future missions to Mars and maybe beyond.

The team found that the bacteria on the floating lab had changed to be different from its Earth-bound counterparts. But that could be a process of evolution as a response to its stressful surroundings, they said.

"There has been a lot of speculation about radiation, microgravity and the lack of ventilation and how that might affect living organisms, including bacteria," said Northwestern's Erica Hartmann, who led the study. "These are stressful, harsh conditions. Does the environment select for superbugs because they have an advantage? The answer appears to be 'no.'"

That is useful because in the future people might have to spend time with that bacteria in places they'll have no escape – the long journeys to the Moon, Mars and maybe further into our solar system. If those microbes appeared to be changing in ways that were dangerous, it could threaten the health of those astronauts.

"People will be in little capsules where they cannot open windows, go outside or circulate the air for long periods of time," said Hartmann. "We're genuinely concerned about how this could affect microbes."

The International Space Station is home to thousands of different microbes, which were carried up into space either on astronauts or in cargo. They will have begun that journey somewhere much easier to live – but now find themselves transported to somewhere far more difficult.

"Bacteria that live on skin are very happy there," Hartmann said. "Your skin is warm and has certain oils and organic chemicals that bacteria really like. When you shed those bacteria, they find themselves living in a very different environment. A building's surface is cold and barren, which is extremely stressful for certain bacteria."

The bacteria that is managing to flourish in the newly harsh conditions appears to be getting selected for its ability to deal with the difficulties of space.

"Based on genomic analysis, it looks like bacteria are adapting to live – not evolving to cause disease," said Ryan Blaustein, a postdoctoral fellow in Hartmann's laboratory and the study's first author. "We didn't see anything special about antibiotic resistance or virulence in the space station's bacteria."

Though the new study could help prove useful for astronauts who will be heading into space, the future of private space travel could offer whole new challenges as weaker and more unhealthy people are offered the option to pay to fly into space.

"Everywhere you go, you bring your microbes with you," Hartmann said. "Astronauts are exceedingly healthy people. But as we talk about expanding space flight to tourists who do not necessarily meet astronaut criteria, we don't know what will happen. We can't say that if you put someone with an infection into a closed bubble in space that it won't transfer to other people. It's like when someone coughs on an airplane, and everyone gets sick."