By Michael Irving July 23, 2023
Bacteriophages seen under the microscope Matthew Dunne / ScopeM / ETH Zurich
Viruses may get a bad rap, but some of them can be helpful to fight off bacterial infections. Scientists at ETH Zurich have demonstrated a new way to use them to diagnose which bacteria is causing a UTI, and then launch a stronger attack against them.
Bacteriophages (or just phages) are a type of virus that preys on bacteria. About a century ago they emerged as a promising way to fight off infections, but research fell flat as soon as penicillin was invented. However, as bacteria are becoming increasingly resistant to antibiotics, phage therapies are seeing a resurgence in interest from scientists.
Now, researchers from ETH Zurich and Balgrist University Hospital have used phages to both diagnose and treat bladder and urinary tract infections (UTIs). There are three main species of bacteria that cause these infections – Escherichia coli, Klebsiella and Enterococci – but tests to identify which one is the culprit in a particular patient can take a few days. Instead, doctors often prescribe antibiotics without necessarily knowing if they’ll work against a patient’s strain.
In the new study, the researchers developed a much faster way to single out the problem bacterium. First the team genetically modified phages that target the three bacteria species so that they would cause their prey to emit light signals. These can then be set loose on a patient’s urine sample, where they can highlight the problem bugs in under four hours, allowing doctors to prescribe the best antibiotic to treat that species. This will improve the outcomes for patients as well as reduce the risk of antibiotic resistance.
In a separate study, the team improved the ability of phages to kill bacteria. They genetically engineered them so that after they infect their targets, they not only produce more phages but also proteins called bacteriocins. These proteins are effective at killing bacteria, especially those that have evolved resistance to phages.
Together, the team says these studies show how phages could help mitigate the rise of superbugs, offering new treatment options that are more targeted. Antibiotics aren’t very selective, wiping out good and bad bacteria in equal measure. But phages act more like snipers, attacking only specific bacteria.
While there’s still a long way to go before phage therapies are widely used in humans, the team plans to soon test the new treatment in patients in a clinical trial.
The two studies were published in the journal Nature Communications.
Source: ETH Zurich
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