🚀 Could this mutant virus from space save lives on Earth?

The laboratories of the International Space Station (ISS) offer a unique observation ground for the evolution of microbes. A recent study reveals that viruses and bacteria adapt there according to entirely new rules. The absence of gravity changes the fundamental rules that govern biological interactions.

Researchers compared the behavior of a virus that attacks bacteria, the T7 bacteriophage, and its host, the bacterium Escherichia coli, on the ISS and on Earth. The results, published in PLOS Biology, show that microgravity does not merely slow down the infection. It steers the evolution of both organisms along distinct trajectories, with specific genetic mutations. This discovery could allow for the design of new treatments against infections resistant to antibiotics.

An initial slowdown followed by rapid adaptation

Under Earth conditions, the T7 phage infects and destroys the E. coli bacterium in less than an hour. Aboard the ISS, this process is considerably delayed, taking several hours, or even days, to establish itself. Scientists attribute this delay mainly to the absence of gravity, which limits random encounters between viral particles and bacterial cells. Fluids do not mix in the same way in microgravity, reducing the contacts necessary for infection.

However, this slowdown does not prevent the infection from occurring. After an incubation period of 23 days in orbit, the phage perfectly succeeded in replicating and persisting in the bacterial environment. This initial adaptation phase has profound consequences, as it alters the context in which evolution operates. The bacteria, stressed by the space conditions, have time to deploy defense mechanisms before the viral attack becomes massive.

Genomic analysis revealed that bacteria exposed to phages in microgravity accumulated distinct mutations, particularly in genes related to their outer membrane and stress response. These adaptations seem to help them survive in the space environment, but also to protect them against viral infection.

Viral mutations with promising terrestrial applications

On the bacteriophage side, evolution in microgravity followed a unique trajectory. The viruses developed mutations on unexpected genes. An advanced technique, deep mutational scanning, allowed mapping the impact of thousands of variants on infection capability.

The most striking result is the practical application of these discoveries. Researchers synthesized phage variants enriched by the mutations that appeared in microgravity and tested them on clinical strains of uropathogenic E. coli, responsible for urinary infections and resistant to the standard T7 phage. Against all expectations, these "space" phages proved significantly more effective at eliminating resistant bacteria than their terrestrial counterparts.

This discovery opens an original pathway for phage therapy, an approach that uses viruses to combat bacterial infections. It demonstrates that extreme physical environments, like microgravity, can serve as discovery platforms to reveal biological solutions invisible under standard conditions. Space thus becomes a laboratory to explore the evolutionary potential of microbes.