The International Space Station (ISS) stands as a testament to human achievement in space exploration. It is known for its highly controlled environment, characterized by elevated solar radiation, increased CO2 levels, and microgravity.

Despite the kind of environment provided by the International Space Station, microorganisms occupy a unique niche. These microbial inhabitants are important in affecting the health and well-being of astronauts on board.

Multidrug-Resistant Bacteria Found Lurking on International Space Station Mutate To Become Functionally Distinct

(Photo: Wikimedia Commons/ NASA)

Unlikely Inhabitants

Since its establishment in 1998, the International Space Station has hosted almost 300 astronauts. These astronauts and cargo shipments have unintentionally brought their microbes with them to space. When astronauts return to Earth after their missions, their microbes stay behind, resulting in a unique microbial community that has grown on the orbital post.

In 2019, experts conducted the first extensive survey of bacteria and fungi aboard the ISS and the whole bunch of microorganisms that live among the astronauts. The survey revealed an astonishing number of microorganisms living in the International Space Station, although their health impacts on astronauts are not entirely clear.

NASA and other space agencies currently use the findings of this research to develop measures for the International Space Station and other long-term space missions. Specific microbes in these indoor spaces have been shown to affect human health by influencing our susceptibility to infectious diseases, allergies, or sick building syndrome. Their impact becomes more crucial for astronauts during flights because of the altered immunity associated with space flight.

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Mutated Strains of Drug-Resistant Bacteria

NASA is very interested in finding out which microbes, and in what quantities, are present on the International Space Station and how the station's microbiome is changing over time. In a recent study, a team of experts took a closer look at bacterial strains on board the International Space Station. They found that these microorganisms have mutated to a different form, genetically and functionally distinct from their Earthly counterparts.

The scientists discovered that bacteria in space become more resistant to treatment or drugs and can openly persist in the microgravity environment in abundance. The study details are discussed in the paper "Genomic, functional, and metabolic enhancements in multidrug-resistant Enterobacter bugandensis facilitating its persistence and succession in the International Space Station."

The microorganisms that live on the International Space Station enjoy environmental conditions more than those living on Earth. As they are affected by various factors like humidity, ventilation, and air pressure, they have learned to adapt to survive.

The scientists behind the research focused on Enterobacter bugandensis, a highly pathogenic species known for causing infections such as endocarditis, bacteremia, osteomyelitis, and septic arthritis. The species is also highly adaptable and can take advantage of unusual conditions to infect a host.

In this study, the research team isolated 13 strains of the bacterial species from the International Space Station for analysis. It was found that Enterobacter bugandensis mutates to become more resistant to antimicrobial treatments under stress. It was also found to coexist with several other microorganisms and may have even helped them survive. This behavior in the microgravity environment may lead to E. bugandensis' dominance on board the International Space Station.

It is still unclear how the space microbe can affect the health of astronauts on board the space station. Still, the researchers call for preventive measures to help mitigate the impacts of mutated bacterial species. It is also unclear whether these microbes can pose health risks to humans on Earth.

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Check out more news and information on the International Space Station in Science Times.