- Mycoplasma genitalium, or M. gen., is resistant to the most common STI drug
- The STI can cause preterm birth, miscarriage and even infertility in women
- Routine testing is not recommended by CDC, so the STI is a ‘silent spreader’
- Up to 20% of US sexually active men and women could be infected unknowingly
A ‘silent-spreader’ STI which can cause infertility is feared to be evolving into a superbug.
Mycoplasma genitalium, also known as M. genitalium or M. gen, has become resistant to every antibiotic used to treat it so far.
The sexually transmitted infection was first discovered in London in the 1980s — but a test has only been available in the US since 2019. It means scientists are unsure exactly how widespread it is.
Some studies suggest just one in 100 adults in the US are positive for M. gen but experts estimate as many as a fifth will get it at some point in their life.
The bacterial infection has been linked to infertility, premature births and miscarriages, as well as cervical swelling and pelvic inflammatory disease.
There are increasing concerns it will become untreatable because the STI has developed resistance to the most popular antibiotic used to treat STIs, azithromycin, as well as quinolone, macrolide and doxycycline.
Alternatives are available but they cause severe side effects that mean they are not suitable for pregnant women. And there are signs it is already becoming tolerant to them, too.
There are also fears M. gen will become more common as STIs on the whole soar in the US. In 2021 there were a record 2.5million infections, up from 2.4million in 2020, itself an all-time high.
Superbugs are estimated to contribute to around 7million deaths per year, with some experts warning they should be taken as seriously as global warming.
Professor Paul Hunter, an expert in infection diseases at the University of East Anglia in England, told DailyMail.com M. gen has the ‘strongest evidence that it causes adverse health outcomes’ of any strain of genital mycoplasma.
The STI is also ‘difficult to diagnose’, meaning it spreads under the radar, he said.
‘Doing something about it is not easy as the infection is pretty common and most infections do not cause adverse health outcomes.’
M. gen can result in painful, bleeding and swollen genitals, and even infertility in women.
But many people will show no symptoms at all and can carry it for years without realizing.
It can be passed on through genital-to-genital contact such as unprotected vaginal or anal sex, as well as mother-to-baby transmission even before birth.
The risk of early birth increased nearly twofold in women with M. gen, an analysis of 10 studies in 2021 found.
In men, M. gen can cause urethritis, swelling and irritation of the urethra, making it painful to pee, but more research is needed to establish the long-term effects of M. gen infection.
It can also cause abnormal discharge for both sexes.
Simon Clarke, associate professor in cellular microbiology at the University of Reading, told DailyMail.com it is ‘entirely feasible’ that M. gen becomes completely resistant to antibiotics.
However, he said multiple drug-resistant strains are probably ‘some way off’.
He said the ‘silent spread’ is the problem, as people ‘don’t know to go and get tested and they spread it on to somebody else’.
This means it will continue to become more dominant, and doctors will continue to prescribe antibiotics to treat it, fueling antibiotic resistance and the potential for M. gen. to become a superbug.
Superbugs are estimated to kill 7 million, either as co-infection or directly, every year.
But a major study last year found they are the main underlying cause of 1.2million annual deaths globally.
This would make superbugs a bigger global killer than AIDS or malaria, which killed 860,000 and 640,000 that year, respectively. In comparison, Covid killed an estimated 3.5million people in 2021.
The Centers for Disease Control and Prevention (CDC) does not recommend routine screening for M. gen.
Because the test, known as the Aptima nucleic acid amplification test was only approved in 2019, it has not been rolled out widely and doctors do not need to report cases of the infection.
Patients will only be screened for M. gen after persistent symptoms and negative tests for other STIs.
This means there is no clear picture of how widespread M. gen is, or who it affects most.
But Lisa Manhart, a professor of epidemiology at the University of Washington School of Public Health, told NBC News that M. gen could be affecting as many as 20 per cent of sexually active women and 17 per cent of men between age 15 and 24.
By contrast, the most common STI in the US is chlamydia, with 5 per cent of sexually active women aged 14-24 infected with the STI.
If common antibiotics do not work, doctors can use moxifloxacin.
This does work but causes significant side effects, including nausea, diarrhoea, dizziness, and vomiting.
This means it is not a suitable treatment for everyone, particularly pregnant women.
And the more moxifloxacin is used to treat M. gen, the more likely it is to become resistant to that as well.
Aside from moxifloxacin, treatment options are limited.
The CDC currently recommends testing for antibiotic resistance prior to deciding which drugs to take, but these tests are not approved by the FDA.
Just a handful of specialized research centers can test whether the infection is resistant to an antibiotic.
Widely available versions of the test could take years, as could antibiotics that work.
Meanwhile, during the Centers for Disease Control and Prevention conference for prevention of sexually transmitted diseases on Monday, executive director of the National Coalition of STD Directors David Harvey said the rise in STIs was ‘out of control’.
Infection rates for STIs including gonorrhea and syphilis have been climbing for years, but last year syphilis cases reached their highest since 1948.