Researchers have developed a dissolving tablet that successfully protects both mice and rabbits from uropathogenic Escherichia coli (UPEC), the bacteria responsible for about 80 percent of urinary tract infections (UTIs). And while the under-the-tongue treatment isn’t yet ready to be trialed in humans, the authors of a new study say their vaccine could one day reduce the need for antibiotics.
The pill itself is composed of peptide-polymer nanofibers that dissolve in the mouth to deliver the vaccine via the oral mucus. Once ingested, the drug primes the immune system to create antibodies that recognize and destroy three different molecules that are found on the surface of UPEC microbes.
Previous studies have identified these particular surface peptides as key targets for the development of a UTI vaccine, yet until now all attempts to stimulate an immune response against these molecules had failed. However, after testing their new vaccine in mice, the study authors found that the animals developed the desired antibodies in their urinary tracts.
As a result, the treatment proved just as effective as high-dose antibiotics at protecting the animals from UTIs. This is hugely significant, since urinary infections are typically treated with antibiotics, leading to concerns about antibiotic resistance and potentially harmful disruption to the microbiome.
Addressing these worries, the study authors state that their vaccine “did not induce notable broad changes in the microbiome of mice.” The fact that none of the antibodies were present in the animals’ poop also indicates that the vaccine doesn’t trigger an immune response in the gastrointestinal tract, and is therefore unlikely to interfere with gut bacteria populations.
Furthermore, while the antibodies generated by the vaccine were able to bind to a harmful UPEC strain, they showed no affinity for other non-pathogenic varieties of E. coli. In other words, they were highly targeted against the microbes that cause UTIs and are unlikely to kill any friendly bacteria.
“In stark contrast, mice treated with the oral antibiotic fosfomycin had significantly altered microbiome composition,” write the study authors.
“Our tablet vaccine raised responses not only in mice but also in rabbits, which have an oral cavity with key similarities to humans,” they add.
Crucially, the fact that the treatment can be taken sublingually may help to make the vaccine more accessible than many current drugs. According to the researchers, the “tablet formulation has been shown to be heat stable, which may reduce or eliminate the high costs and infrastructure required for cold-chain distribution of a vaccine and enable a far greater global distribution compared to vaccines that are dependent on refrigeration.”
Further animal studies are now needed to confirm the safety and efficacy of the treatment, although the authors say their findings provide a “strong initial indicator” that the vaccine could work for humans.
The study has been published in the journal Science Advances.
[H/T: New Scientist]