Just when you thought you had your sexual health knowledge on lock, Mycoplasma genitalium (MG) enters the chat. 

More "notorious” STIs like chlamydia, gonorrhoea and HIV are fairly well known, as are consequences if left untreated. Chlamydia can result in infertility, gonorrhoea is becoming more and more resistant to antibiotics, and HIV leads to AIDS. Even HPV, which isn’t strictly classified as an STI, is known because it can lead to cervical cancer. But when it comes to mycoplasma, the infection isn’t well understood. 

Nevertheless, a recent study has suggested that over 1% of adults in the UK and US could be infected with mycoplasma, which is being dubbed the “new superbug”. So here’s everything you need to know about this new type of STI. 

What is Mycoplasma genitalium? 

Mycoplasma genitalium, also known as mgen, is a bacterium that was first identified in 1981 but wasn’t classified as an STI until 2015, after a study published in the Journal of Epidemiology found a link between the bacteria and sexual activity. 

MG is spread through genital-to-genital or genital-to-rectal contact, mainly through unprotected sex, and you're less likely to contract the infection through oral sex.

It’s the smallest known bacteria of its kind, which makes it very hard to culture and analyse in a lab. It can live in your urogenital tract (vagina, uterus, Fallopian tubes and urethra) without causing any issues, but if the bacteria multiply and take over, that’s when it causes an infection. Mycoplasma is treated with antibiotics, but not the same types used for other STIs or infections. 

Fairly little is known about Mycoplasma genitalium, and it’s mostly asymptomatic, which makes it very hard to detect. In 2018 the British Association of Sexual Health and HIV (BASHH) even released draft guidance due to concerns that if MG is missed and not treated properly, it can become resistant to antibiotics and even harder to treat. 

What are mycoplasma symptoms?

As with most STIs, you may not even know you have Mycoplasma genitalium. When it does cause symptoms, they’re frustratingly common. Painful intercourse, a burning sensation when you pee, bleeding between periods, and unusual vaginal discharge are all possible symptoms of Mycoplasma genitalium… as well as loads of others STIs. 

The biggest hurdle with MG is figuring out that you have it, and as with many STIs, Mycoplasma genitalium can hang around for years. This means that you can be diagnosed with MG even if you’re in a faithful, long-term relationship. It doesn’t mean your partner has been cheating, but rather that one of you has had it all along and just didn’t know. 

If you’re experiencing symptoms and think you have MG, speak to your GP. They’ll have to rule out other possible infections before testing for mycoplasma. 

To test for mycoplasma, your doctor will take a vaginal swab, but mycoplasma testing is not yet part of a routine sexual health screening, so it won’t show up when you get an STI check.

Many clinics also won’t test for MG unless you have symptoms, which are uncommon with MG. And even if you do have symptoms, they can easily be mistaken for another STI or vaginal infection. You can, however, get tested for MG at cost through a private clinic. 

Is Mycoplasma genitalium serious?

Complications from STIs disproportionately affect women, and mycoplasma is no exception. In itself it’s not a dangerous infection, but if left untreated it can lead to bigger problems.  

Studies have found a link between mycoplasma and cervicitis, an inflammation of the cervix, and pelvic inflammatory disease (PID), suggesting that when left untreated, mycoplasma could be a strong risk factor for PID.

PID is a common consequence of untreated STIs, and happens when an infection travels to the upper reproductive tract, infecting the fallopian tubes and often leading to fertility problems. Studies detected Mycoplasma genitalium in women with cervicitis, suggesting that the organism is more common in women with cervicitis than those without. 

Given how little we know about Mycoplasma genitalium and the long-term effects it has on women, along with a lack of accessible routine testing, more research is needed on this type of STI and how it affects reproductive health.