Drug-resistant gonorrhoea could be treated with a UTI antibiotic

Gonorrhoea is resistant to nearly all antibiotics, but one commonly used for urinary tract infections (UTIs) may be able to treat drug-resistant cases.

The sexually transmitted infection (STI) is caused by Neisseria gonorrhoeae, a bacterium that can infect various parts of the body, including the genitals and urethra. Common symptoms include a burning pain when urinating and discharge from the vagina or penis. If left untreated, the infection can raise the risk of infertility and premature birth.

Standard treatment involves an injection of ceftriaxone, the last antibiotic that works against most N. gonorrhoeae strains, but some have evolved to resist this drug too, especially in Asia. “We know drug-resistant strains will spread elsewhere. In fact, we’ve already seen this with cases in North America and Europe that were imported from Asia,” says Vanessa Allen at the University of Toronto in Canada, who wasn’t involved in the study.

If ceftriaxone doesn’t work, the World Health Organization (WHO) recommends a subsequent dose of another class of antibiotics, but it is only a matter of time before completely untreatable strains emerge, as bacteria are constantly evolving to evade antibiotics, says Allen.

In an attempt to buy some time, Caroline Perry at pharmaceutical company GlaxoSmithKline in Pennsylvania and her colleagues looked at around 400 people with N. gonorrhoeae infections in their genitals and urinary tracts. About half were randomly assigned to take two oral doses of the antibiotic gepotidacin. Commonly used for UTIs, this isn’t recommended to treat gonorrhoea, but it showed promise in a smaller trial.

The remaining participants received a single injection of ceftriaxone plus one oral dose of azithromycin, which belongs to a different antibiotic class. Although taking these at the same time isn’t recommended by the WHO, combining azithromycin with the first-line treatment ceftriaxone sets a higher bar with which to compare gepotidacin against, says Allen.

Between four and eight days later, the researchers analysed swabs from 370 of the participants, with the remaining ones having dropped out or returning poor quality samples. The team found that both treatment regimens cleared all of the participants’ infections.

“It’s incredibly promising,” says Allen. “It shows a new treatment that’s highly effective and is very much easier to administer than the current antibiotic that’s given as a shot in the arm or the buttocks.”

Although the study didn’t include people with ceftriaxone-resistant strains of infection, gepotidacin works by preventing N. gonorrhoeae from replicating its DNA, while ceftriaxone destroys the bacterium’s rigid outer layer. These different mechanisms of action may mean that strains with mutations that enable them to resist ceftriaxone shouldn’t yet be able to resist gepotidacin, says Allen.

Still, if gepotidacin became widely used, N. gonorrhoeae would probably eventually evolve resistance to it too, so it is important to tackle the STI in other ways, such as by developing a vaccine that prevents infections, says Allen. What’s more, checking what strains people carry before prescribing antibiotics could reduce the inappropriate use of such drugs, which can worsen resistance rates, she says.