Diagnosis and Treatment of Mycoplasma Genitalium

Common bacteria linked to STIs in women and men

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

Concerned woman in bed
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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.

Related Conditions

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's symptoms include:

  • Vaginal itching
  • Burning with urination
  • Pain during intercourse
  • Bleeding between periods or after sex
  • With bacterial vaginosis, a fishy odor after sex and changes in vaginal discharge

Men may experience:

  • Urethral discharge
  • Burning when urination
  • Pain and swelling of the joints (arthritis)

MG is the most common cause of non-chlamydial NGU 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.

Doctors do have 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.

Most experienced clinicians today generally assume MG is involved in both BV and NGU infections. According to the Centers for Disease Control and Prevention, between 15% and 20% 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 be detected in up to 30% of women with symptoms of cervical inflammation or infection.


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

While other antibiotics may be substituted for azithromycin, 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 often are ineffective.

Treatment Problems

The presumption of MG in cases of NGU and treatment failures related to it highlight a growing problem with syndromic treatment of STIs. Syndromic treatment is when doctors treating a class of diseases all the same way, without testing for their cause.

This type of treatment exposes people to medications that may not work as well as the treatment doctors would choose if they knew the actual cause. In bacterial infections, 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. The concern is that, in time, no treatments for this common STD will be reliable.

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