In an effort to learn more about astronaut health and the effects of space on the human body, NASA is conducting a new experiment aboard the International Space Station to speed up the detection of antibiotic-resistant bacteria, thus improving the health safety not only of astronauts but patients back on Earth.
Infections caused by antibiotic-resistant bacteria can be difficult or impossible to treat, making antibiotic resistance a leading cause of death worldwide and a global health concern.
Future astronauts visiting the Moon or Mars will need to rely on a pre-determined supply of antibiotics in case of illness. Ensuring those antibiotics remain effective is an important safety measure for future missions.
The Genomic Enumeration of Antibiotic Resistance in Space (GEARS) experiment, which is managed by NASA’s Ames Research Center in California’s Silicon Valley, involves astronauts swabbing interior surfaces across the space station and testing those samples for evidence of antibiotic-resistant bacteria, and in particular Enterococcus faecalis, a type of bacteria commonly found in the human body. The experiment is the first step in a series of work that seeks to better understand how organisms grow in a space environment, and how those similarities and differences might help improve research back on Earth.
“Enterococcus is a type of organism that’s been with us since our ancestors crawled out of the ocean, and is a core member of the human gut,” said Christopher Carr, assistant professor at the Georgia Institute of Technology and co-principal investigator of GEARS. “It’s able to survive inside and outside of its host, which has allowed it to become the second highest leading cause of hospital-acquired infections. We want to understand how this type of organism is adapting to the space environment.”
The GEARS experiment seeks to improve the detection and identification of these bacteria, building on existing efforts to understand what organisms grow on the station’s surfaces.
“We’ve been monitoring the surfaces of the space station since 2000, but this experiment will give us insight beyond the identities of present organisms, which is currently all that is used for risk assessment,” said Sarah Wallace, a microbiologist at NASA’s Johnson Space Center in Houston and co-principal investigator of GEARS. “With the station orbiting close to Earth, it’s a low-risk space to evaluate and learn more about the frequency of this bacteria and how it responds to the space environment so we can apply this understanding to missions to the Moon and Mars, where resupplies are more complex.”
Over the next year, astronauts will swab parts of the station and analyze samples by adding an antibiotic to the medium in which the samples will grow. The results will reveal where this and other resistant bacteria are growing and whether they can persist or spread across the station.
Sarah WAllace
NASA Microbiologist
The experiment was originally launched to the ISS on the 30th SpaceX commercial resupply services (CRS) mission in March 2024, and the first round of GEARS testing turned up surprising results: very few resistant bacteria colonies, none of which were E. faecalis. This bodes well for the threat of antibiotic resistance in space.
“There was some cleaning done before swabbing the station, which may have removed some bacteria,” said Carr. To better understand how and where risky bacteria may live, the astronauts paused some cleaning before the second round of swabbing.
“We want the astronauts to have a clean environment, but we also want to test those high-touch areas, so they intentionally and briefly avoided cleaning some areas so we can understand how bacteria may grow or spread on the station.”
This experiment is the first study to perform metagenomic sequencing in space, a method that analyzes all the genetic material in a sample to identify and characterize all organisms that are present, an important research and medical diagnostic capability for future deep space missions.
The GEARS team hopes to create a rapid workflow to analyze bacteria samples, reducing the time between swabbing and test results from days to hours. That workflow could be applied in hospitals and make a huge impact when treating hospital-acquired infections from antibiotic-resistant microbes.
The result could save lives – more than 35,000 people die each year as a result of antibiotic-resistant infections. The issue is personal to Wallace, who lost a family member to a hospital-acquired infection.
“It’s not that uncommon: so many people have experienced this kind of loss,” said Wallace. “A method to give an answer in a matter of hours is huge and profound. It’s my job to keep the crew healthy, but we’re also passionate about bringing that work back down to Earth. I hope we can shine a light on rapidly analyzing bacteria: if we can do this in space, we can do it on Earth, too.”
Genomic Enumeration of Antibiotic Resistance in Space (GEARS) was funded by the Biological and Physical Sciences Space Biology Program, with pioneering funding and support from the Mars Campaign office.
