BASHH recommends that MG is treated with a seven-day course of the antibiotic, doxycycline, followed by a course of azithromycin. Left unchecked, they say this could result in thousands of women each year at increased risk of infertility from pelvic inflammatory disease caused by MG.
That is because it is commonly misdiagnosed as Chlamydia, another STI.
In women, it can cause inflammation of the reproductive organs (womb and fallopian tubes) too, causing pain and possibly a fever and some bleeding.
Once it becomes resistant to antibiotics, MGen could leave up to 4,800 women infertile each year in the United Kingdom, according to the association.
Paddy Horner, who co-wrote the guidelines, said: "These new guidelines have been developed, because we can't afford to continue with the approach we have followed for the past 15 years as this will undoubtedly lead to a public health emergency with the emergence of MG as a superbug".
"It's about time the public learned about Mycoplasma genitalium", Greenhouse said. You can't shut down easyJet, the internet, Tinder and Grindr, all of which make it easier to find new partners.
You can get it by having unprotected sex with someone who has it. Condoms can prevent this spread. "So people need to take precautions".
Almost half of 16 to 24-year-olds admit they have had sex with a new partner without using a condom, a Public Health England report said in December. The infection was only discovered in the 1980s, yet scientists didn't know until years later that it was actually transmitted via sex.
But this trend was reversed following declining concern about HIV, with the emergence of effective new antiviral treatments reducing the consequences of an HIV diagnosis from a death sentence to a treatable condition.