The World Health Organisation on Friday said antibiotic resistance was making gonorrhoea, a sexually transmitted infection, much harder and impossible to treat.
Experts at WHO said it was only a matter of time before last-resort antibiotics would be powerless to halt the spread of the disease.
Gonorrhoea remains a major public health concern and affects an estimated 78 million people each year, mostly women, leading to pelvic inflammatory disease, ectopic pregnancy and infertility, as well as increasing the risk of Human Immunodeficiency Virus.
WHO said at least three people — in France, Japan and Spain — were infected with an untreatable strain of the disease, which they might have spread to others through sex.
A human reproduction specialist at the Geneva-based United Nations health agency, Teodora Wi, said, “Gonorrhoea is a very smart bug. Every time you introduce a new type of antibiotic to treat it, this bug develops resistance to it.
“These [three] cases may just be the tip of the iceberg, since systems to diagnose and report untreatable infections are lacking in lower-income countries where gonorrhoea is actually more common.”
A WHO study found that from 2009 to 2014, there was widespread resistance to the first-line medicine ciprofloxacin, increasing resistance to another antibiotic drug called azithromycin, and the emergence of resistance to last-resort treatments known as extended-spectrum cephalosporins.
In a Sky News report, Wi said in most countries, ESCs were the only single antibiotic still effective against gonorrhoea, but resistance to them had already been reported in 50 countries.