By Stephen Beech
Research in space could help fight drug-resistant superbugs such as E. coli, say scientists.
An experiment partially conducted on board the International Space Station (ISS) showed that viruses and bacteria interact differently in microgravity.
Bacteria-infecting viruses and their hosts accumulate distinctive mutations in near-weightlessness, according to the study.
Researchers found that terrestrial bacteria-infecting viruses were still able to infect their E. coli hosts in near-weightless “microgravity” conditions aboard the ISS.
But the dynamics of virus-bacteria interactions differed from those observed on Earth.
The research team say their findings could help tackle soaring antibiotic-resistant infections that cause urinary tract infections.
Study lead author Dr. Phil Huss, of the University of Wisconsin-Madison, explained that interactions between phages – viruses that infect bacteria – and their hosts play an “integral” role in microbial ecosystems.
Dr. Huss said: “Often described as being in an evolutionary “arms race,” bacteria can evolve defenses against phages, while phages develop new ways to thwart defences.
“While virus-bacteria interactions have been studied extensively on Earth, microgravity conditions alter bacterial physiology and the physics of virus-bacteria collisions, disrupting typical interactions.
“However, few studies have explored the specifics of how phage-bacteria dynamics differ in microgravity.”
For the new study, Dr. Huss and his colleagues compared two sets of bacterial E. coli samples infected with a phage known as T7 – one set incubated on Earth and the other aboard the ISS.
Analysis of the space-station samples showed that, after an initial delay, the T7 phage successfully infected the E. coli.
However, whole-genome sequencing revealed “marked” differences in both bacterial and viral genetic mutations between the Earth samples versus the microgravity samples.
Dr. Huss said: “The space-station phages gradually accumulated specific mutations that could boost phage infectivity or their ability to bind receptors on bacterial cells.
“Meanwhile, the space-station E. coli accumulated mutations that could protect against phages and enhance survival success in near-weightless conditions.”
The research team then applied a high-throughput technique – known as “deep mutational scanning” – to more closely examine changes in the T7 receptor binding protein, which plays a key role in infection.
The findings, published in the journal PLOS Biology, revealed further “significant” differences between microgravity and Earth conditions.
Dr. Huss said: “Additional experiments on Earth linked these microgravity-associated changes in the receptor binding protein to increased activity against E. coli strains that cause urinary tract infections in humans and are normally resistant to T7.
“Overall, this study highlights the potential for phage research aboard the ISS to reveal new insights into microbial adaption, with potential relevance to both space exploration and human health.”
He added: “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.”
