Researchers from the Indian Institute of Technology Madras and Nasa Jet Propulsion Laboratory have uncovered alarming evidence of the evolution of a strain of bacteria on the International Space Station distinct from their counterpart strains found on Earth.
The study, led by Principal Investigator Dr. Kasthuri Venkateswaran, focused on strains of the bacterial species Enterobacter bugandensis, a notorious multi-drug resistant pathogen.
"Our comprehensive analysis illuminated not only the ways these interactions sculpt microbial diversity but also the factors that might contribute to the potential dominance and succession of E. bugandensis within the ISS environment," the researchers said in the paper.
Over the course of a two-year mission, dubbed Microbial Tracking 1, the team isolated 13 distinct strains of E. bugandensis from various locations aboard the ISS.
Detailed genomic analysis revealed that these space-dwelling strains had undergone significant genetic mutations, rendering them functionally and genetically distinct from their Earth-based counterparts.
"The unique stresses of the space environment, unlike any found on Earth, appear to be driving these genomic adaptations," explained Dr. Venkateswaran. "The ISS strains have developed resistance mechanisms that classify them as part of the ESKAPE pathogen group, known for their formidable resistance to antimicrobial treatments."
Alarmingly, the study found that the space-evolved E. bugandensis strains were not only able to persist viably on the ISS over extended periods but also exhibited a significant abundance, coexisting with multiple other microorganisms and potentially aiding their survival.
The researchers conducted a comprehensive analysis, mapping the prevalence and distribution of E. bugandensis across the ISS over time, as well as investigating the intricate microbial interactions within the space station's ecosystem.
Their findings pointed to the need for vigilant monitoring and mitigation strategies to ensure the safety of astronauts and the integrity of space habitats.
The paper was published in April 2024, months before Indian-origin astronaut Sunita Williams reached the Space Station on her mission to certify the Starliner spacecraft. However, Nasa maintains that "Closed human-built environments, such as the ISS, are unique areas that provide an extreme environment subject to microgravity, radiation, and elevated carbon dioxide levels."
Nasa added that any microorganisms introduced to these areas must adapt to thrive. By delving into microbial dynamics in extreme environments, this research opens doors to effective preventative measure for astronaut health.
