The World Health Organization has warned the public to cultivate the use of condoms during sex as it's becoming dangerous for those who take part in oral sex.

It warns that if someone contracts gonorrhea through oral sex, it's now much harder to treat, and in some cases impossible.

Experts say the situation was “fairly grim” with few new drugs on the horizon as the sexually transmitted infection is rapidly developing resistance to antibiotics.

According to WHO, about 78 million people pick up the STI each year risking infertility, while analysed data from 77 countries have shown gonorrhea's resistance to antibiotics was widespread.

Dr. Teodora Wi, from the WHO, said there had even been three cases – in Japan, France, and Spain – where the infection was completely untreatable.

She said: “Gonorrhea is a very smart bug, every time you introduce a new class of antibiotics to treat gonorrhea, the bug becomes resistant.”

Worryingly, the vast majority of gonorrhea infections are in poor countries where resistance is harder to detect. “These cases may just be the tip of the iceberg,” she added.

According to her, Gonorrhea can infect the genitals, rectum, and throat, but it is the last that is most concerning health officials.

Dr. Wi said antibiotics could lead to bacteria in the back of the throat, including relatives of gonorrhea, developing resistance.

She said: “When you use antibiotics to treat infections like a normal sore throat, this mixes with the Neisseria species in your throat and this results in resistance.” Adding that 'In the US, resistance [to an antibiotic] came from men having sex with men because of pharyngeal infection.

The Organization also warned that thrusting gonorrhea bacteria into this environment through oral sex can lead to super-gonorrhea if there is a decline in condom use.

They are now calling on countries to monitor the spread of resistant gonorrhea and to invest in new drugs.

In the report, Dr. Manica Balasegaram, from the Global Antibiotic Research and Development Partnership, said: “The situation is fairly grim. “There are only three drug candidates in the entire drug [development] pipeline and no guarantee any will make it out.”

But ultimately, the WHO said vaccines would be needed to stop gonorrhea.

Reacting to the report, Prof Richard Stabler, from the London School of Hygiene & Tropical Medicine, said:

“Ever since the introduction of penicillin, hailed as a reliable and quick cure, gonorrhea has developed resistance to all therapeutic antibiotics.

“In the past 15 years, therapy has had to change three times following increasing rates of resistance worldwide.

“We are now at a point where we are using the drugs of last resort, but there are worrying signs of treatment failure due to resistant strains has been documented.”