For years, scientists have conducted studies aboard the International Space Station (ISS) to determine the effects of living in space on humans and microorganisms. In addition to the high levels of radiation, there is also concern that long-term exposure to microgravity could cause genetic mutations. Understanding this and proposing countermeasures is essential for humanity to become a true kind of space.
Interestingly, a team of researchers from Northwestern University recently conducted a study with bacteria that was kept on board the ISS. Contrary to what many suspected, the bacteria were not mutated into a super drug-resistant strain, but mutated to adapt to their environment. These results could be vital when it comes to understanding how living beings will adapt to the stressful environment of space.
The study describing the team's finding recently appeared in the mSystems, a scientific journal published by the American Society of Microbiology. The study was led by Erica Hartmann, badistant professor in the Department of Civil and Environmental Engineering (DCEE) at NWU, and included multiple graduate and postdoctoral researchers from DCEE and Sarah Castro-Wallace of NASA's Johnson Space Center.
Studies like this are essential for missions that are planned for the near future, which include NASA's plans for renewed missions to the lunar surface and its proposed manned mission to Mars. On top of that, China, Russia and India also plan to send astronauts to the Moon in the coming decades. As Professor Hartmann explained in a NWU press release:
"There has been much speculation about radiation, microgravity and lack of ventilation and how it could affect living organisms, including bacteria. These are stressful, hard conditions. Do you select the environment for superbugs because they have an advantage? The answer seems to be no. "
For the sake of their study, Hartmann and his badociates consulted data from the National Biotechnology Information Center (NCBI), which maintains file information on experiments with microbes carried on board the ISS. Specifically, they evaluated how strains of bacteria Staphylococcus aureus and Bacillus cereus grew in space.
The first is found in human skin and contains the MRSA strain resistant to drugs, which makes it responsible for several infections that are difficult to treat in humans. The latter lives on the ground and has few implications for human health, but still provided valuable information on how terrestrial microbes grow when they withdraw from their comfort zone and undergo the unknown conditions of space.
"The bacteria that live on the skin are very happy there," Hartmann said. "Your skin is hot and has certain oils and organic chemicals that the bacteria really like. When you eliminate those bacteria, they find themselves living in a very different environment. The surface of a building is cold and sterile, which is extremely stressful for certain bacteria. "
When the team compared how these strains grew on board the ISS and how the same strains grow on Earth. What they found was that the bacteria living in the ISS mutated to adapt to local conditions, selecting advantageous genes to be able to continue feeding, grow and function in microgravity and when exposed to higher levels of radiation.
Ryan Blaustein, a postdoctoral fellow in Hartmann's lab who was the first author of the study, indicated that this was a surprising result. "Based on the genomic badysis, it seems that the bacteria are adapting to life, not evolving to cause disease," he said. "We did not see anything special about antibiotic resistance or virulence in the space station bacteria."
This is certainly good news for future astronauts, not to mention people who hope to participate some day in the growing space tourism industry. In both cases, the gangs are forced to live, work and generally spend their time in small capsules or modules where there is no ventilation and the air circulates for long periods of time.
Given the health risks, knowing that terrestrial bacteria will not mutate into super germs that are even more resistant to antibiotics is certainly a relief. Of course, Hartmann and his colleagues also emphasized that this study does not mean that germs can not proliferate once they enter a spacecraft or aboard a space station:
"Wherever you go, you bring your germs with you. Astronauts are extremely healthy people. But while we talk about expanding space flight to tourists that do not necessarily meet the criteria of astronauts, we do not know what will happen. We can not say that if you put someone with an infection in a closed bubble in space, it will not be transferred to other people. It's like when someone coughs up on a plane and everyone gets sick. "
As always, space exploration poses many risks, and the possibility of sending astronauts on longer trips or tourists into space presents many challenges. Fortunately, we have decades of research to rely on and lots of cutting-edge experiments to help inform us before that day arrives.
This study was possible thanks to the support provided by the Searle Leadership Fund and the National Institutes of Health (NIH).
Additional readings: Northwestern University, mSystems