The Earth's bacteria are evolving to survive in space. Several strains sourced from the International Space Station (ISS) differed from the same strains on Earth, having qualities specifically adapted to the Earth's orbit. While it is still unclear what kind of danger these bacteria pose, scientists are looking at ways to protect astronauts from potential superbugs.
A study published in the journal bioRxiv examined five species of bacteria and found they had "uniquely adapted" to space. The lead author of the study, Kasthuri Venkateswaran, told New Scientist: "These microbes have found ways to live and possibly even thrive in space, and understanding how they do this could have big benefits for space exploration and health."
This is not the first time that such bacteria have flourished. A separate study, also headed by Venkateswaran, looked at 13 strains of the drug-resistant bacteria Enterobacter bugandensis from the ISS and found that they had evolved in ways distinct from their Earth-bound counterparts.
Much of this evolution is related to the ISS itself. "Closed human-built environments" are "unique areas that provide an extreme environment subject to microgravity, radiation and elevated carbon dioxide levels", said a press release for the 13 strain study.
Unfortunately, the bacteria in the ISS may have also become more virulent. The species showed "enhanced activity of certain genes linked to bacterial virulence, including those that help them evade and damage the immune system", said New Scientist. "They can also form biofilms: slimy layers that stick to surfaces and can help bacteria resist antibiotics and disinfectants." The threat level to humans is unknown, though researchers are concerned for the health of astronauts. | 
