For years, scientists on board the International Space Station (ISS) have been carrying out research to determine the effects of life in space on humans and microorganisms. In addition to high levels of radiation exposure, there is also concern that long-term exposure to microgravity could cause genetic mutations. Understanding this and taking countermeasures is essential if humanity is to become a genuinely space-promoting species.
Interestingly, a research team from Northwestern University recently conducted a study on bacteria stored aboard the ISS. Unlike many suspects, the bacteria did not mutate into a drug-resistant superstate, but mutated to adapt to their environment. These results could be crucial to understanding how living things will adapt to the stressful environment of space.
The study, which describes the team's findings, recently appeared in mSystems a scientific journal published by the American Society of Microbiology. The study was led by Erica Hartmann, assistant professor at the Department of Civil and Environmental Engineering (DCEE) at the NWU, and included several DCEE alumni and postdoctoral fellows, as well as Sarah Castro-Wallace of the NASA Johnson Space Center.
Studies like these are essential for missions planned in the near future. These include NASA's plans for renewed missions to the lunar surface and their planned occupation to Mars. In addition, China, Russia and India plan to send astronauts to the moon in the coming decades. Professor Hartmann said in an NWU press release:
"There has been much speculation about radiation, microgravity, and lack of ventilation and how this could affect living organisms, including bacteria. These are exhausting, harsh conditions. Does the environment choose superbugs because they have an advantage? The answer seems to be "no".
For their study, Hartmann and her staff consulted National Center for Biotechnology Information (NCBI), which provides archived information on on-board microbial experiments ISS In particular, they examined how the bacterial strains Staphylococcus aureus and Bacillus cereus grew in space ,
The former is found on human skin and contains the drug-resistant strain MRSA, which makes it responsible for several human infections that are difficult to treat. The latter lives in the soil and has little impact on human health, yet provides valuable information on how terrestrial microbes grow when they are removed from their comfort zone and exposed to the unfamiliar conditions of space.
"Bacteria that live on the skin are very happy there," said Hartmann. "Their skin is warm and contains certain oils and organic chemicals that bacteria really like. When you discard these bacteria, they live in a completely different environment. The surface of a building is cold and barren, which is extremely strenuous for certain bacteria.
When the team compared how these tribes grew on board the ISS, they compared the development of the same strains on Earth. They found that bacteria living on the ISS mutated to adapt to local conditions and selected beneficial genes to help them continue to feed, grow and function in microgravity and higher levels of radiation exposure.
Ryan Blaustein, a postdoctoral fellow in Hartmann's lab, the first author of the study, said it was a surprising result. "Based on genome analysis, bacteria seem to adapt to life – and not evolve to cause disease," he said. "We have not seen anything special about antibiotic resistance or virulence in the bacteria of the space station."
This is certainly good news for future astronauts, not to mention people who want to join an emerging space tourism. In both cases, crews have to live, work and, generally, spend time in tiny capsules or modules with no ventilation and air circulation for a long time.
Given the health risks, it is certainly a relief to know that terrestrial bacteria do not mutate into super-germs, which are even more resistant to antibiotics. Of course, Hartmann and her colleagues also emphasized that this study does not mean that germs can not multiply when they get into a spacecraft or aboard a space station:
"Wherever you go, bring your microbes with you. Astronauts are extremely healthy people. But as we talk about the expansion of space flight to tourists who do not necessarily meet the criteria of astronauts, we do not know what's going to happen. We can not say that if you put someone with an infection in a closed bubble in space, it will not be transmitted to other people. It's like someone is coughing on the plane and everyone gets sick. "
Space exploration, as always, carries many risks, and the prospect of sending astronauts on long trips or tourists into space presents many challenges. Fortunately, we can rely on decades of research and do many innovative experiments to keep us informed before the day comes.
This study was made possible thanks to the support of the Searle Leadership Fund and the National Institutes of Health (NIH).
Further reading: Northwestern University mSystems