Neil Armstrong, Katy Perry, and phages all have one thing in common: they have all been to space! In 2025, a team of researchers sent a kind of virus called a phage and the bacterium E. coli aboard the International Space Station. They found that, under conditions of very low gravity, or microgravity, certain processes and physiologies of phages and bacteria were altered compared to their Earth-bound counterparts. There are impressive global health implications to these new findings, which may even overshadow Katy Perry’s brief stint in space.

Phages are some of the most abundant biological entities in the world. Short for bacteriophages, they are viruses that selectively infect certain bacteria. The relationship between phages and bacteria was first adapted into a therapy in 1919. Phage therapy was initially controversial due to its variable results, inconsistent documentation, and general skepticism of their existence until more than 20 years later, when they were visualized using electron microscopy in the 1940’s. By this time, however, a new discovery claimed the spotlight: penicillin .

This common and powerful antibiotic was used globally as the main line of defense against bacterial infections. Due to the success of antibiotics, much of the scientific attention on phage therapies was redirected. Unfortunately, excessive and incorrect antibiotic use over the years has caused widespread bacterial resistance. In response to this global health crisis, some researchers have refocused on phage therapy.

Antibiotics are considered broad-spectrum, killing many types of bacteria that may even be beneficial. Phages, however, are hyper-specialized, with each phage damaging a very narrow array of bacteria. Lytic phages are particularly employed in phage therapy, as they bind to their desired bacteria and cause lysis, or the rupture of the cell. The specificity of phages could be the answer to combating very stubborn multidrug-resistant bacteria that antibiotics can no longer fight.

But what does this have to do with space? Phil Huss and his colleagues at the University of Wisconsin experimented with one set of T7 phages and E. coli on Earth, and another set inside the International Space Station. Under a microgravity environment, there was a delay in the phages infecting the E.coli, which would ultimately be attributed to genetic mutations both parties underwent. From consequent genome sequencing, the set was found to exhibit genetic differences unique from their terrestrial counterparts. The space phages acquired mutations that enhanced their ability to bind with receptors on the E. coli cells, and the E. coli acquired mutations to protect against these phage attacks.

Back on Earth, the researchers performed a technique called deep mutational scanning, which isolated the amino acid differences that caused the protein functionality changes. Changes were observed in the T7 receptor protein, which plays a crucial role in the phage’s ability to infect E. coli.

This experiment has exposed an active and adaptive side to phage-bacteria interactions. With a deeper understanding of the phage’s infection mechanism, researchers can now potentially engineer phages against drug-resistant infections. Filling in where antibiotics have failed, phage therapies are finally “roaring” into the public health scene… leaving a Katy Perry-sized legacy, to say the least.