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Antibiotic-Resistant Bacteria Discovered on International Space Station Toilet

Shaunacy Ferro|
NASA, Wikimedia Commons
NASA, Wikimedia Commons | NASA, Wikimedia Commons

Antibiotic resistance isn’t just a problem on Earth. It’s happening in space, too. LiveScience reports that NASA scientists have found drug-resistant bacteria in samples from one of the space toilets on the International Space Station.

As part of a study published in the journal BMC Microbiology, scientists from NASA’s Jet Propulsion Laboratory looked at waste samples taken from the ISS in 2015. They isolated five strains of Enterobacter bugandensis bacteria, sequencing their genomes and analyzing their susceptibility to antibiotics. They compared these space strains to strains found on Earth, including some that have been linked to patients in hospital settings.

Normally, because of the lack of interplanetary sewers, astronaut waste is simply flushed into space, where it will incinerate on its way back through Earth’s atmosphere. But for the sake of NASA’s ongoing catalog of microbes found on the ISS, some lucky astronaut got to swab the station’s toilet for samples. They also swabbed the station’s Advanced Resistive Exercise Device, one of the exercise machines astronauts use on the ISS to keep up muscle mass during long periods living in microgravity.

The space toilet where astronauts collected microbial swabs
The space toilet where astronauts collected microbial swabs | Jack Fischer, NASA

Based on their similarity to bacteria strains taken from patients on Earth, the analysis found that the strains isolated from the ISS swabs have a 79 percent probability that they could cause disease in humans. They contained genes associated with antibiotic resistance and toxic compounds.

"Given the multi-drug resistance results for these ISS E. bugandensis genomes and the increased chance of pathogenicity we have identified, these species potentially pose important health considerations for future missions,” the study's lead author, Dr. Nitin Singh, said in a statement. “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." That means that while astronauts don't need to worry about these bacteria just yet, antibiotic resistance is an issue that NASA will need to prepare for in the future.

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