Understanding the behavior of bacteria in microgravity of space is important for protecting astronauts.
In March 2015, researchers at NASA JPL analyzed samples taken from the toilet and the exercise platform on the ISS and identified five strains of bacterium Enterobacter in space environment. Those strains were not harmful to humans, but researchers believe they could represent a key step toward protecting astronauts from bacterial diseases during long term missions in space.
When researchers compared the ISS strains with publicly available genomes of 1,291 Enterobacter strains collected on Earth, they found that bacteria in space were closely resembled to the Earth’s.
“To show which species of the bacteria were present on the ISS, we used various methods to characterize their genomes in detail. We revealed that genomes of the five ISS Enterobacter strains were genetically most similar to three strains newly found on Earth. These three strains belonged to one species of the bacteria, called Enterobacter bugandensis, which had been found to cause disease in neonates and a compromised patient, who were admitted to three different hospitals (in east Africa, Washington state and Colorado).” Dr. Kasthuri Venkateswaran, a researcher at Jet Propulsion Laboratory Biotechnology and Planetary Protection Group, said in a statement.
Previous research has shown that bacteria behave differently in the microgravity of the International Space Station. Even some species found to thrive more in space than here on Earth. The resilience of bacteria in microgravity environment or a lack thereof has important implications for future space missions.
“Given the multi-drug resistance results for these ISS E. bugandensisgenomes and the increased he increased chance of pathogenicity we have identified, these species potentially pose important health considerations for future missions,” said lead author Dr. Nitin Singh. “However, it is important to understand that the strains found on the ISS were not virulent, which means they are not an active threat to human health, but something to be monitored.”
Researchers found that strains of Enterobacter that were isolated from ISS had similar antimicrobial resistance patterns to the three strains found on Earth. Computer analysis revealed that bacterium has 79 percent probability to cause disease.
“Whether or not an opportunistic pathogen like E. bugandensis causes disease and how much of a threat it is, depends on a variety of factors, including environmental ones,” said Dr. Venkateswaran. “Further in vivo studies are needed to discern the impact that conditions on the ISS, such as microgravity, other space, and spacecraft-related factors, may have on pathogenicity and virulence.”