Viruses that evolved in space stations and returned to Earth proved more effective at killing bacteria, according to a study conducted aboard the International Space Station (ISS). This phenomenon is attributed to the unique evolutionary arms race between bacteria and phages, the viruses that infect them, in microgravity conditions. The study, published in PLOS Biology, reveals that microgravity fundamentally alters the speed and nature of phage infection, leading to slower infection cycles and more efficient phage adaptations. On Earth, gravity constantly stirs the fluids bacteria and viruses exist within, but in space, everything floats without stirring. This difference in fluid dynamics affects the frequency of bacterial-phage interactions, forcing phages to adapt to a slower pace and become more efficient at grabbing onto passing bacteria. Experts believe that understanding this alternative form of phage evolution could lead to the development of new phage therapies, which use phages to kill bacteria or make them more vulnerable to traditional antibiotics. The study's findings also have practical applications on Earth, as the space-adapted phages showed increased activity against E. coli strains that commonly cause urinary tract infections, which are typically resistant to the T7 phages. However, the cost of sending phages into space or simulating microgravity on Earth must be considered to achieve these results.
