International Space Station – Microbial matters.
Credit: Roscosmos


A new Northwestern University study has found that — despite its seemingly harsh conditions — the International Space Station (ISS) is not causing bacteria to mutate into dangerous, antibiotic-resistant superbugs.

However, the bacteria are instead simply responding, and perhaps evolving, to survive in a stressful environment.

The new findings suggest that the most crucial bacterial functions involved in this potential adaptive response are specific to bacterial lifestyle and do not appear to have direct impacts on human health.

Onboard the ISS.
Credit: NASA

Stressful, harsh conditions

“There has been a lot of speculation about radiation, microgravity and the lack of ventilation and how that might affect living organisms, including bacteria,” said Northwestern’s Erica Hartmann, who led the study.

“These are stressful, harsh conditions,” Hartmann adds in a university press statement. “ Does the environment select for superbugs because they have an advantage? The answer appears to be ‘no.’”

Hartmann is an assistant professor of environmental engineering in Northwestern’s McCormick School of Engineering. The research was published earlier this month in the journal mSystems, a publication of the American Society for Microbiology.

NASA astronaut Scott Kelly, a flight engineer for Expedition 43 and a member of the one-year crew, is seen here inside the ISS Unity module.
Credit: NASA

Microbial housing

The ISS houses thousands of different microbes, which have traveled into space either on astronauts or in cargo. The National Center for Biotechnology Information maintains a publicly available database, containing the genomic analyses of many of bacteria isolated from the orbiting outpost.

Hartmann’s team used that data to compare the strains of Staphylococcus aureus and Bacillus cereus on the ISS to those on Earth.


Enclosed environments

As the prospect of sending travelers to Mars gain momentum, there has been an increasing interest in understanding how microbes behave in enclosed environments.

Credit: Blaustein, Ryan et al.

“People will be in little capsules where they cannot open windows, go outside or circulate the air for long periods of time,” Hartmann points out. “We’re genuinely concerned about how this could affect microbes.”

Closer to home, Hartmann also notes: “Everywhere you go, you bring your microbes with you. Astronauts are exceedingly healthy people. But as we talk about expanding space flight to tourists who do not necessarily meet astronaut criteria, we don’t know what will happen.”

Research findings

“Based on genomic analysis, it looks like bacteria are adapting to live — not evolving to cause disease,” adds Ryan Blaustein, a postdoctoral fellow in Hartmann’s laboratory and the study’s first author. “We didn’t see anything special about antibiotic resistance or virulence in the space station’s bacteria.”

Although this is good news for astronauts and potential space tourists, Hartmann and Blaustein are careful to point out that unhealthy people can still spread illness on space stations and space shuttles.

For a look at the research findings — Pangenomic Approach To Understanding Microbial Adaptations within a Model Built Environment, the International Space Station, Relative to Human Hosts and Soil – go to:

Also, take a look at this informative video about the new study results:

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