The US Centres for Disease Control (CDC) has reported that gonorrhoea is now developing resistance to the last two antibiotics able to treat it.

In other words, the sexually transmitted disease is on the verge of being resistance to all antibiotics, and untreatable by current medicine.

Or in even more words, condoms have never looked so good.

An estimated 820,000 people are infected with the Neisseria gonorrhoeae bacteria each year in the US - with more than half of those aged between 15 and 24.

Right now, doctors are using a combination of two antibiotics, azithromycin and ceftriaxone - to treat the disease, a strategy they'd hoped would stop the bacteria from becoming resistant to either of the drugs in the near future.

But now research has shown that resistance both antibiotics is on the rise in the US.

In 2014, the percentage of gonorrhoea samples that were shown to be resistant to azithromycin rose from 0.6 to 2.5 percent - a four-fold increase.

The percentage of ceftriaxone resistance doubled from 0.4 to 0.8 percent.

That's still small - and the cases that were resistance to those two drugs were able to be treated by other antibiotics - but the increase is a red flag for CDC researchers.

"It is low. But what we do know is that this bacteria has demonstrated the ability, repeatedly, to develop antibiotic resistance to the drugs that have been used for it," Robert Kirkcaldy told health and medicine publication, STAT.

"The potential for untreatable gonorrhoea is a very real possibility in the future."

And that's not ideal, seeing as gonorrhoea can cause pain, burning, discharge, and long-term complications that can increase the risk of infertility. If the bacteria gets into the blood, it can on rare occasions become fatal.

So why is gonorrhoea so good at avoiding antibiotics? Researchers still aren't sure, but part of the problem is that when the bacteria becomes resistant to a drug, it doesn't lose that resistance.

That means it's still able to dodge antibiotics that haven't been used to treat it in decades. Companies are now working on developing new antibiotics, but they could take years to get on the market.

Kirkcaldy wouldn't speculate on how quickly gonorrhoea could become resistance to all antibiotics, but said it was a matter of "when and not if".

In the meantime the best way to fight the bacteria is to stop it spreading in the first place - and that means regular condom use.

And don't worry, scientists are working on making that better, too.