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29th August 2025
10:19am BST
Half a million people have tested positive for an 'untreatable' STI that has been quietly on the spread.
The little-known sexually transmitted infection has been making it's way through Australians down under as half a million people have tested positive for the infection.
The STI known as mycoplasma genitalium, shortened to Mgen or MG, can cause infertility and miscarriages as well as genital pain and bleeding.
Despite this, symptoms can go undetected for years in people unknowingly carrying it.
Mgen is transmitted through genital-to-genital contact as well as passed from mother to baby during pregnancy.
There are growing fears that the STI is 'untreatable' due to it being already resistant to most antibiotics and becoming increasingly resistant to more antibiotics.
Meanwhile, other treatments exist, but these can cause severe side effects and are unsuitable for pregnant women.
Even more concerningly, there are signs the infection is becoming resistant to these alternatives.
Professor Catriona Bradshaw from Monash University's Melbourne Sexual Health Centre told the Mail: "You can't really see it under the microscope, and it's got a really, really tiny genome that is highly error prone.
"So it throws up these random mutations and it doesn't have a DNA repair mechanism. That means it randomly acquires antibiotic resistance very easily, and that is very different to chlamydia.
"Unfortunately, you may need several courses to cure the infection due to increasing antibiotic resistance.
"And some of these antibiotics can have side-effects. Occasional, but serious, side-effects include an abnormal heart rhythm, rupture of tendons, and nerve damage."
The symptoms of the infections vary by sex.
Men may experience mild irritation, itching, a burning sensation when urinating, or penile discharge (clear or pus-like).
Women may notice vaginal discharge, bleeding, or pain during sex. In some cases, it progresses to pelvic inflammatory disease, which is linked to infertility.
Professor Bradshaw said: "So a woman might have deep abdominal pain with sex, she might bleed after sex, generally not so much an abnormal discharge although it can happen.
"It's really much more of a pelvic inflammatory disease, which is pain and abnormal bleeding, and there's evidence it can lead to infertility.
"But mostly, it is very, very commonly asymptomatic, with symptoms not just driven by the bug but also your immune response."
Studies show that in the UK, the rate is similar to chlamydia at 1-2 per cent.
