Earlier this year, a 30-year-old woman injured in a bombing suffered from a super-bug infected wound. In the course of 700 days, the infection showed no signs of clearing — reflecting a growing concern globally about the rise of antibiotic-resistant bacteria. Scientists express concern that our dependence on antibiotics may eventually overcome our defenses against some of the most potent diseases.
But the woman’s treatment offers a hint of an answer. Doctors infused a virus to help her fight the bacterial infection — and it worked. This is because viruses and bacteria have been locked in an ancient battle with one another that far predates our own existence. Known as bacteriophages, some viruses have the unique ability to infect bacteria while evading the bacterium’s defence mechanisms. One of the ways they achieve this is by building a shield wall around their own genetic material, thereby protecting themselves against the bacterium’s defenses.
Now, these phages have emerged as a new horizon for treating antibiotic resistance in people. While such treatment is still experimental, a new study published in Naturelast week showed how some “jumbo” phages are able to defend themselves as they infect bacteria.
“Over billions of years of conflict with bacteriophages (phages), plasmids, and other mobile genetic elements, bacteria have evolved an array of defensive systems to target and destroy foreign nucleic acids [the viruses’ genetic material],” the paper noted.
“In turn, phages have evolved mechanisms, including anti-restriction and anti-CRISPR proteins, that counter specific bacterial defense systems.” Leveraging these mechanisms could be key to overcoming antibiotic resistance.
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In jumbo phages, one protein is primarily responsible for this — called chimallin, “after the chimalli, a shield carried by ancient Aztec warriors,” the researchers noted. The protein builds a fishnet or honeycomb structure around the viruses’ genetic material.
The key thing about this mechanism is that the shield keeps the bacterium’s defense mechanisms out, while also selectively importing and exporting key materials needed for it to replicate itself. “These discoveries present us with a whole new era of phage biology,” said Elizabeth Villa, who co-authored the paper.
Researchers believe that phage therapy can be used in conjunction with antibiotics to treat superbug infections. “I see this [experiment] as convincing evidence that you can get antibiotic and phage synergy,” commented Paul Turner, a professor of ecology and evolutionary biology at Yale University, about the woman whose bomb injuries were treated with phages.
The race to find solutions to treat antibiotic resistance in bacteria is ramping up; even as newer antibiotics are developed to help, bacteria are increasingly becoming resistant to these too. Recently, scientists developed ways to inhibit an important protein in bacteria that’s key to its replication — but the chemical used for this isn’t safe to use in humans just yet.
“Antibiotic resistance is a crisis of a magnitude we haven’t yet come to terms with — a phenomenon that leaves us defenseless against deadly bacteria, killing more people globally every year than malaria and AIDS, according to a 2019 Lancet analysis,” The Swaddle noted earlier. As we emerge from a global viral pandemic, these organisms may represent an unlikely ally in our ever-precarious fight against other Frankenstein-like microbes of our own making.
