Viruses that evolved in space and returned to Earth proved more adept at killing bacteria, according to a study conducted aboard the International Space Station (ISS). This phenomenon is attributed to the unique evolutionary pressures of microgravity, which alter the dynamics of the ongoing arms race between bacteria and their phage infectors. The research, published in PLOS Biology, sheds light on the space-based evolution of these microorganisms and offers valuable insights for developing more effective treatments against antibiotic-resistant bacteria on Earth. The study's findings suggest that microgravity significantly impacts the speed and nature of phage infection, with the process taking longer in space compared to Earth. This is due to the reduced fluid mixing in microgravity, which affects the interactions between bacteria and phages. The lead researcher, Srivatsan Raman, confirmed the hypothesis that infection cycles in microgravity are slower, as fluids don't mix as effectively as they do on Earth. This discovery has implications for the development of phage therapies, which utilize phages to combat bacteria or make them more susceptible to traditional antibiotics. Nicol Caplin, an astrobiologist at the European Space Agency, suggests that understanding the genetic adaptations of phages in microgravity could lead to more effective treatments for resistant bacteria on Earth, potentially accelerating the optimization of antibiotics. Whole-genome sequencing revealed that both bacteria and phages on the ISS accumulated distinct genetic mutations not observed in Earth samples. Space-based viruses developed mutations that enhanced their ability to infect bacteria and bind to bacterial receptors. Conversely, E. coli bacteria evolved mutations that protected against phage attacks and improved their survival in microgravity. Deep mutational scanning further confirmed the practical applications of these adaptations. When the space-adapted phages were transported back to Earth and tested, they demonstrated increased activity against E. coli strains commonly causing urinary tract infections, which are typically resistant to the T7 phages. This unexpected finding highlights the potential of space-based evolution in improving phage therapies. However, the study also emphasizes the need to consider the cost of sending phages into space or simulating microgravity on Earth to replicate these results. The research has broader implications for astronaut health during long-term space missions and could contribute to the development of more effective phage therapies for use in microgravity environments.
