Recurrent UTIs could one day be prevented with a vaccine instead of antibiotics if promising results in mice and rabbits are replicated in clinical trials
Health 23 November 2022
By Alice Klein
E. coli bacteria seen through an electron microscope
STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY
A vaccine tablet that dissolves under the tongue protects against urinary tract infections (UTIs) in mice and rabbits. If it is shown to work in people, it could reduce the need to treat these infections with antibiotics.
More than half of all women get at least one UTI in their lifetime and about 5 to 10 per cent experience three or more per year.
These recurrent infections are often managed with daily antibiotics to prevent overgrowths of the Escherichia coli (E. coli) bacteria that cause most UTIs. However, long-term antibiotic use can lead to bacteria becoming resistant to antibiotics and disrupt healthy populations of gut bacteria, leading to gastrointestinal symptoms.
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As an alternative to antibiotics, Sean Kelly and Joel Collier at Duke University in North Carolina and their colleagues have developed a vaccine for preventing UTIs.
It trains the immune system to recognise and fight UTI-causing bacteria by exposing it to three peptide molecules that are found on the surface of these microbes.
It has been formulated as a tablet that dissolves under the tongue. This mode of vaccine delivery can elicit immune responses in the urinary tract due to similarities between the mucous membranes lining the mouth and urinary tract.
The tablet can be self-administered and is stable at room temperature, making it easy to store, transport and use. “Eliminating the cold-chain requirement has the potential to lower costs of vaccine delivery,” says Kelly.
In mice, the vaccine worked as well as high-dose antibiotics for preventing UTIs, and a follow-up experiment in rabbits also demonstrated protective effects.
Because the vaccine was targeted specifically against UTI-causing bacteria and not healthy bacteria, it didn’t upset the normal mix of gut bacteria in the animals.
The team hopes these promising results will pave the way for human clinical trials, says Collier. “We will need to conduct biodistribution and safety studies before clinical trials, and we are actively seeking partners to accomplish this,” he says.
Another under-the-tongue vaccine for preventing UTIs, called MV140, is being developed by Spanish company Inmunotek. In a recent clinical trial involving 240 women with recurrent UTIs, nearly 60 per cent of those who received the vaccine had no UTI episodes during the nine-month follow-up period, compared with 25 per cent of those who received a placebo.
The MV140 vaccine comes as a liquid that must be sprayed under the tongue twice daily for three to six months. It is unclear how long the protection from the new dissolvable tablet would last in people and whether booster tablets would be required, but “even with boosters, it would be a less disruptive paradigm than antibiotic use”, says Kelly.
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