The FDA Just Approved the First Test for Mycoplasma Genitalium, a Commonly Misdiagnosed STI
The CDC called it an “emerging issue” in 2015, but we wouldn’t blame you if you knew little or nothing about Mycoplasma genitalium (M. genitalium), a type of bacteria that causes a sexually transmitted infection. But despite the bit of mystery surrounding M. genitalium, the infection can cause serious issues if left untreated. Thankfully, a new test may help doctors diagnose it more accurately.
Earlier this month, the FDA authorized the marketing of a new test—Hologic’s Aptima Mycoplasma genitalium Assay—to help with the diagnosis of M. genitalium, according to an FDA release. The test can be performed using vaginal, endocervical, or urethral swab, as well as a urine sample, Damon Getman, Ph.D., senior principal research scientist and director of research at Hologic, tells SELF. While some labs have used their own testing methods for M. genitalium up until now, those tests are not FDA-approved, and it’s unclear how accurate they are. The new test is available now.
What is M. genitalium, exactly?
“Similar to chlamydia and gonorrhea, M. genitalium is a bacterial STI that is transmitted during sexual contact,” Lisa Manhart, Ph.D., professor of epidemiology and global health at the University of Washington, tells SELF. It can be transmitted via bodily secretions (as can chlamydia and gonorrhea), but the infection doesn’t present in your skin the way HPV or herpes does, SELF explained previously.
The infection isn’t totally understood, but we do know that “it also has many of the same risk factors as chlamydia and gonorrhea, including younger age and multiple sex partners,” Manhart says.
M. genitalium infections don’t always cause noticeable symptoms. And when they do, they’re often confused with other STIs. In particular, the symptoms or M. genitalium are similar to those of chlamydia. For instance, when chlamydia causes symptoms (it often doesn't!), they tend to be things like abnormal discharge, pain or burning while peeing, pain during sex, bleeding between periods, and lower abdominal pain, the Mayo Clinic says. And M. genitalium can cause vague symptoms that overlap with those, such as pelvic pain, spotting between periods, odd discharge, and vaginal irritation.
So it’s understandable that the average adult (and even their doctor) might mistake the infection for something else. But this confusion surrounding M. genitalium can lead to misdiagnosis, which, in turn, could result in the wrong type of treatment, leaving the actual infection untreated. Without treatment, M. genitalium infections have been linked to cervicitis (an inflammation of the cervix), urethritis (when the urethra becomes irritated), and pelvic inflammatory disease, which can cause infertility down the line.
Treatment for M. genitalium isn’t necessarily the same as treatment for chlamydia and gonorrhea.
Although there aren’t currently any guidelines for treating an M. genitalium infection specifically, the CDC treatment guidelines recommend standard antibiotics for people with urethritis, cervicitis, and pelvic inflammatory disease. “When M. genitalium is suspected in people with these disease syndromes, the recommended antibiotic is azithromycin,” Manhart says.
However, she continues, resistance to azithromycin has been documented in some people with M. genitalium. In some places, almost 60 percent of those with the infection show resistance. And the other standard antibiotic for these issues, doxycycline, doesn’t work for everyone either.
On top of all that, doctors have been prescribing these antibiotics based on results from the previously available testing methods or without testing at all. “Historically it has been very difficult to get a test for M. genitalium, so most of the time people get these antibiotics without knowing whether or not they have M. genitalium,” she explains.
An accurate test, though, will allow doctors to know for sure what they’re dealing with, and possibly give their patients a different antibiotic (moxifloxacin), which has shown more promise in treating these infections than other options, Manhart says.
FDA commissioner Scott Gottlieb, M.D., also touched on this in the press release: “Patients with unidentified urogenital infections are typically treated with antibiotics, some of which may not be effective against M. gen. … In the past, it has been hard to diagnose this organism. By being able to detect it more reliably, doctors may be able to more carefully tailor treatment and use medicines most likely to be effective.”
The hope is that the new test will make it easier to accurately test for and treat M. genitalium.
Although some large commercial laboratories offer tests for M. genitalium that they have developed themselves, these are not FDA-approved, Manhart explains. Because they haven’t undergone the same rigorous validation process that is required for FDA approval, we don’t really know how accurate they are when it comes to detecting M. genitalium. And while some large research universities are able to test for M. genitalium and for antibiotic resistance, this is not available in routine health care, she explains.
The FDA marketing authorization of the new test was partly based on a prospective study looking at more than 11,700 samples collected from 3,393 people visiting 21 clinical sites across the U.S. The test was able to successfully identify M. genitalium in about 90 percent of vaginal, male urine, male urethra, and penile samples. However, the test wasn’t quite as good when it came to female urine and endocervical samples; it correctly identified M. genitalium 81.5 percent and 77.8 percent of the time, respectively. Importantly, the test was also able to successfully identify when samples did not contain M. genitalium more than 97 percent of the time.
This test really is the first of its kind, Manhart says.
In the meantime, if you’re experiencing any unusual symptoms, Manhart recommends talking to your health care provider to help determine your individual risk factors and to find out which STI tests are appropriate for you. If your symptoms could also point to a M. genitalium infection, it’s reasonable to ask about that when discussing testing or treatment. The same goes for if you get a positive STI result even without symptoms—it’s worth bringing up M. genitalium with your doctor.
And, of course, rely on your safer sex practices (using a condom, for instance) as much as you possibly can.
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