The Real Truth about Mycoplasma Genitalium, the "New STI." A Word from our Medical Director.

By Mary Diana, M.D.
Note: this article has been minimally edited for public consumption.

I’m writing to let you know about a “new STI” which you might be reading about in the media.

Mycoplasma is a class of bacteria, of which there are six different species. Five of them inhabit the genitourinary tract. The species Mycoplasma pneumoniae infects the respiratory tract, causing what is commonly referred to as “walking pneumonia.” Mycoplasma hominis is another well-known species in Ob/Gyn, and is often related to pregnancy complications including miscarriage, pre-term labor, low-birth weight, neonatal infection, and stillbirth.

Mycoplasma genitalium is the species that is recently in the lay press and is being called the “new STI”. This species was first identified in the early 1980s and has been recognized as a common cause of male urethritis, representing 15-25% of nongonococcal urethritis in men. Symptoms include pain during urination and discharge from the penis. In women, it is less clear what role it plays, and has not been well-studied. It can be found in the vagina, cervix, and endometrium. Much like Chlamydia and Gonorrhea, there are usually no symptoms in women. There is some evidence that it may cause pelvic inflammatory disease (PID), although it appears that this only occurs in 5% of women who are infected. Studies looking at its relationship to infertility are conflicting. More research needs to be done.

There is good evidence that M. genitalium is transmitted sexually. As far as incidence of infections goes, it is more common than Gonorrhea but less common than Chlamydia, depending on the population studied.

Currently there are no FDA-approved tests for Mycoplasma genitalium. Cultures can take up to 6 months and there are only a few labs in the world that can do this. In research settings, M. genitalium is diagnosed using a method called NAAT (nucleic acid amplification test) which detects the genetic material of the bacteria (this is the same type of test we currently use for Chlamydia and Gonorrhea). It can be detected in urine as well as cervical, vaginal, and urethral swabs. Again, this test is not FDA-approved and is not commercially available. Even if it were available, screening the general population would not necessarily be recommended, and testing would be limited to patients who have symptoms of urethritis, cervicitis, or PID.  Unfortunately, treatment is not straightforward. 

Hopefully we will be able to test for this infection in the near future, but at this time, testing is not available. This is another great reason to encourage condom use!!

If you have further questions, please contact your local Planned Parenthood Health Center.