Doctors are pushing for more research into a little-known sexually transmitted disease that may be more common than thought.
Scientists have known about mycoplasma genitalium, or M. genitalium or M. gen., a sexually transmitted infection that can cause genital pain, bleeding, and swelling, and has been linked to infertility and miscarriage. However, it was only in 2019 that the first Food and Drug Administration-approved test for M. gen. became commercially available. Many cases can go undiagnosed and untreated, doctors warn.
“It’s a real concern,” said Dr. Irene Stafford, an associate professor of maternal-fetal medicine at UTHealth Houston’s McGovern Medical School. “Why don’t we investigate this?”
Stafford called for more research and testing for the bacterial infection on Tuesday at the Centers for Disease Control and Prevention conference on the prevention of sexually transmitted diseases, where CDC officials warned of a “out of control” rise in STDs.
Equivalent to chlamydia and gonorrhea, M. gen. is sometimes asymptomatic, but it can lead to serious complications in both men and women. In men, it can cause urethritis, a swelling and irritation of the urethra. In females, M. gen. is associated with cervical swelling, pelvic inflammatory disease, miscarriage, premature birth, and infertility. In May, a large study appeared in the magazine Sexually Transmitted Infection found that the risk of preterm birth was nearly twice as high in women with M. gene.
However, more research is needed to determine the long-term risks of M. gene infection, experts say.
What are symptoms?
Because testing is relatively new, doctors are not required to report diagnosed cases, and the CDC does not recommend routine screening, it’s not clear how common the STI is or who is most at risk. A patient is usually only screened for it if symptoms persist after testing negative for other STIs.
“We’ll learn more about the epidemiology of sexually transmitted diseases when we have better testing methods,” said Erik Munson, an assistant professor of laboratory medical science at Marquette University in Milwaukee.
Symptoms may include:
- Pain and discomfort while urinating.
- Abnormal discharge for both men and women.
- Women may also experience lower abdominal pain and bleeding after sex.
As many as 20% of sexually active women and 16.5% of men ages 15 to 24 may be infected with M. gen., according to Lisa Manhart, a professor of epidemiology at the University of Washington School of Public Health.
In comparison: chlamydia, the most reported STD in the US ranges from 4% to 7% for sexually active young women, depending on location and risk factors.
Given its association with pregnancy complications, Stafford believes that high-risk pregnant women should be screened for M. gene. But screening programs can be expensive, especially without more research into the risks available to justify the cost.
“We have really good studies showing that if we screen and treat chlamydia and gonorrhea, we can prevent infertility and PID [pelvic inflammatory disease]Manhart said. “We don’t have that kind of evidence for M. genitalium.”
The call for more research is urgent — the bug has developed resistance to the most common antibiotic used to treat STDs, azithromycin or the “Z-Pack,” according to the CDC.
Another antibiotic, moxifloxacin, is effective but can cause serious side effects, making it a particularly risky choice for pregnant women. Plus, the more exposure to moxifloxacin M. gene. the more likely it will become resistant to that antibiotic, experts warn. Besides moxifloxacin, there are very few treatments for the infection.
“M. genitalium has rapidly developed resistance to every antibiotic that has been used to treat it,” Manhart said. “We already have untreatable infections.”
While these cases are rare, some worry that M. gene is on its way to becoming a fully drug-resistant superbacter. Until scientists find new treatments for the STI, public health experts are approaching treatment with caution.
For now, the CDC says the best strategy for treating M. gene is to test for antibiotic resistance before deciding which drugs to use. However, those tests are not FDA-approved.
“The CDC is putting a lot of stock in resistance testing, and right now it’s not readily available,” Munson said.
Only a few specialized research centers can test whether the infection is resistant to an antibiotic. As companies work on widely available versions, they may be years away, as well as new or reused antibiotics that are effective against the persistent bug, Munson said.
Experts hope that greater public awareness of the STI could give a much-needed boost to research efforts.
“Because the implications of untreated M. gene. on fertility and sexual health is real,” Stafford said.