Diagnosis and Treatment of Mycoplasma Genitalium

Common bacteria linked to STIs in women and men

concerned woman In Bed
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Mycoplasma genitalium (MG), has only recently started to be recognized as a significant health concern. It is a relatively common bacteria that was discovered in the 1980s. At that point, mycoplasma was thought to be harmless, effectively "hitching a ride" on the back of other diseases rather than causing disease on its own.

These days, that's no longer true. Mycoplasma genitalium is thought to be a significant cause of sexually transmitted infections (STIs) with scientists only just beginning to give it the full attention it deserves.

Understanding Mycoplasma Genitalium

Since the 1990s, it has been clear that Mycoplasma genitalium is the prime rather than secondary cause of many infections, including forms of bacterial vaginosis (BV) and non-gonococcal urethritis (NGU). It has also been associated with pelvic inflammatory disease (PID) and implicated in other infections once attributed to other bacteria.

By and large, most cases of MG are asymptomatic. If symptoms do appear, they are largely nonspecific and easily mistaken for other STIs such as chlamydia and gonorrhea. Mycoplasma genitalium symptoms also differ significantly in women and men:

  • Women tend to experience vaginal itching, burning on urination, and pain during intercourse. They may also find themselves bleeding between periods or after sex. MG is also associated with bacterial vaginosis, the symptoms of which can include a fishy odor after sex and changes in vaginal discharge.
  • Men, on the other hand, may experience urethral discharge, burning on urination, and pain and swelling of the joints (arthritis). MG is the most common cause of non-chlamydial non-gonococcal urethritis in men.

Challenges in Diagnosis

The main barrier to diagnosing MG is that there is no approved blood test to confirm infection. Direct diagnosis requires a bacterial culture, which takes up to six months to grow. There are other ways to directly identify mycoplasm genitalium, but those tests are mostly reserved for research.

Because of this, MG is usually diagnosed presumptively. In other words, a doctor will assume MG is the cause of a person's symptoms after they have made an effort to rule out all other options.

To most experienced clinicians today, MG is generally assumed to be involved in both BV and NGU infections. According to the Centers for Disease Control and Prevention, 15 to 20 percent of non-gonococcal urethritis cases are directly caused by MG. MG is implicated in one out of every three cases of persistent or recurrent urethritis. Mycoplasma can also be detected in 10 to 30 percent of women with symptoms of cervical inflammation or infection.


Mycoplasma genitalium is standardly treated with antibiotics, most commonly a single 1g dose of azithromycin. While azithromycin is considered safe and effective, there is now evidence of increasing resistance to the drug in populations where it broadly used.

While other antibiotics may be substituted, doxycycline is considered less effective (albeit with a lower risk of resistance). An extended course of moxifloxacin has been shown to be very effective in some studies. However, shorter courses are associated with treatment failure.

Issues with treatment failures in cases of NGU because of the presence of MG highlight a growing problem with the syndromic treatment of STIs. Syndromic treatment is where doctors treating a class of diseases in the same way, without testing for their cause. This type of treatment presumptively exposes a person to medications that may not work as well or effectively as the treatment that would be chosen if the cause of the disease was known. In the event of a bacterial infection, using the wrong drug can also potentially add to the already huge problem of antibiotic-resistant bacteria. Growing concerns about antibiotic-resistant gonorrhea have led to multiple changes in the recommended treatment regimen over the past decade. There are concerns that, in time, no reliable treatment will be available for this common STD.

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