Scientists have discovered that bacteria-infecting viruses sent to the International Space Station evolve in unexpected ways compared to Earth conditions. In microgravity, these viruses and their bacterial hosts undergo distinct genetic changes, potentially improving treatments for drug-resistant infections. The findings, from a study aboard the ISS, highlight how space alters microbial interactions.
Researchers exposed Escherichia coli bacteria to T7 phages—viruses that infect bacteria—both on Earth and in the microgravity environment of the International Space Station. The experiment, led by Phil Huss from the University of Wisconsin-Madison, revealed that while infections occurred in space after an initial delay, the evolutionary paths diverged significantly from terrestrial samples.
Whole-genome sequencing of the space samples showed that T7 phages developed mutations enhancing their infectivity and ability to bind to bacterial receptors. Meanwhile, the E. coli bacteria in microgravity acquired genetic alterations that bolstered defenses against the phages and improved survival in weightless conditions. These differences were further explored using deep mutational scanning on the T7 receptor binding protein, a critical component for infection.
Earth-based follow-up tests linked these microgravity-induced changes to greater effectiveness against E. coli strains responsible for human urinary tract infections, which typically resist T7 phages. The study, published on January 13 in PLOS Biology, suggests that space-based research could uncover novel microbial adaptations with applications for space travel and health on Earth.
As the authors noted, "Space fundamentally changes how phages and bacteria interact: infection is slowed, and both organisms evolve along a different trajectory than they do on Earth. By studying those space-driven adaptations, we identified new biological insights that allowed us to engineer phages with far superior activity against drug-resistant pathogens back on Earth."
This work underscores the value of the ISS for advancing phage therapy, a promising alternative to antibiotics amid rising antimicrobial resistance.
