The toilet on the International Space Station (ISS) is home to strains of Enterobacter bacteria that are similar to recently discovered multi-drug resistant bacteria on Earth. That’s the result of a recent study out of NASA’s Jet Propulsion Laboratory at the California Institute of Technology.
The five strains identified on the ISS showed patterns of antimicrobial resistance similar to the bacteria discovered on Earth. Unlike the latter, the ISS strains do not pose a threat to human health, according to the study, but should be monitored.
The discovery was spurred by a desire to create a comprehensive list of the microbial life aboard the ISS.
“Although microbial monitoring has always been a component of ISS operations, our initial research effort focused on creating a more complete identification of the microbial ‘passengers’ on the ISS, including bacteria that are naturally present on the human body and those that may be present in cargo,” Nitin Singh, a microbiology researcher at JPL who worked on the study, told Digital Trends. “The goal is to understand how they fit into the station’s microbiome, and what potential effects they could have on the ISS inhabitants.”
The researchers analyzed samples collected from the toilet and exercise platform aboard the ISS in March 2015. Once the bacteria were identified, they compared the outer space strains to the genomes of the nearly 1,300 Enterobacter strains sequenced on Earth.
The study revealed that the ISS strains were not harmful to humans but shared characteristics with antimicrobial resistant pathogenic bacteria on Earth.
“The microbial strains that were found in our study were not virulent, meaning none poses a threat to human health,” Singh said. “But this study highlights why it’s essential to monitor the microbiome of the ISS. Keeping an eye on how microbes grow and adapt, lets us take better care of astronaut health, and could teach us how to be more efficient on where and how frequently to clean different parts of the station.”
Moving forward, the JPL researchers will continue to monitor these microbes, paying special attention to their potential threat to the health of astronauts.
“Frankly, we have just started to take a snapshot of how microbes survive in space,” Singh said. “There are lots of unknowns. Microbes were here on Earth for billions of years before us and will be here for billions of years after we are gone. Our understanding of them is just a couple of centuries old, so we have a lot to understand and put them in the right order, and ISS microbial research is a unique opportunity to perhaps learn how these organisms adapt in a non-Earth environment. Our research results will not only be important for the health of future space travelers but the new knowledge most certainly will help us prevent or treat infectious diseases here on Earth.”
A paper detailing the study was published last week in the journal BMC Microbiology.