“I’m not small, I’m just streamlined!” Image of Mycoplasma genitalium adapted from American Society for Microbiology.

In November and December of last year, headlines touting a “new” STD made an ever-so-minor flurry across the Internet. CNN referred to it as “mycoplasma genitalium, or MG” — Mycoplasma genitalium is the name of the teardrop-shaped bacteria that can cause several diseases in the urinary or reproductive tracts, such as urethritis and pelvic inflammatory disease.

M. genitalium is the smallest living organism known to science, having “devolved” from more complex organisms — but that doesn’t mean it can’t pack a punch! While these bacteria have surely been around for millennia, we only discovered them in the 1980s. Since then, we’ve known that M. genitalium fits the profile of a sexually transmitted pathogen — the only reason it made the news last year was that a team of British researchers published further evidence that this bug is indeed sexually transmitted and capable of causing disease.

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Genital mycoplasmas can be cured — but a doctor needs to know what she’s looking for in order to prescribe the correct antibiotic!

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An infection with M. genitalium could more generally be called a “genital mycoplasma.” The term “genital mycoplasmas” refers to a category of several different species of sexually transmitted bacteria, most notably Mycoplasma genitalium, but also less common species, such as Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum. M. genitalium is considered an “emerging pathogen,” because it is only over the past couple of decades that technology has allowed us to study these bacteria, along with other genital mycoplasmas.

Risk factors for infection include multiple sexual partners and not using condoms during sex. It is thought that most people with an M. genitalium infection don’t have immediate symptoms — 94 percent of infected men and 56 percent of infected women won’t notice anything amiss. That doesn’t mean it can’t do damage.

M. genitalium can cause urethritis (inflammation of the urethra) in the male population. Urethritis is characterized by discharge, difficult or painful urination, or itching — classic symptoms of many STDs. Urethritis can be caused by several types of microorganisms, most commonly manifesting as gonorrhea or chlamydia. However, it’s thought that M. genitalium is responsible for 30 percent of persistent or recurrent urethritis in males, and that it is more common than gonorrhea but not as common as chlamydia. What we don’t know is whether or not an infection with M. genitalium can have long-term consequences for males, such as infertility.

The havoc that M. genitalium might wreak on a female reproductive system was clarified last year, when a team of researchers published a meta-analysis of all the data published since 1980. They found that M. genitalium was significantly associated with several gynecological problems:

• cervicitis (inflammation of the cervix): Cervicitis can make vaginal intercourse painful, and can cause vaginal discharge or bleeding — in fact, the British team found that women infected with M. genitalium were six times more likely to bleed after vaginal intercourse than uninfected sexually active women. M. genitalium occurs in up to 30 percent of women diagnosed with cervicitis.
• pelvic inflammatory disease (PID): Infection with M. genitalium more than doubles one’s risk for pelvic inflammatory disease, or PID, which can lead to infertility, chronic pelvic pain, and increased risk for ectopic pregnancy. While PID is usually caused by gonorrhea or chlamydia, M. genitalium occurs in up to 22 percent of PID cases. There is also some evidence that M. hominis can cause PID as well.
• preterm birth (also called premature birth): Infection with M. genitalium nearly doubles the risk for preterm birth, in which a baby is born before a pregnancy has reached 37 weeks. Because the last few weeks of pregnancy are so crucial to a baby’s development, being born too early can lead to death or disabilities, such as breathing, vision, or hearing problems, as well as cerebral palsy and developmental delays.
• miscarriage: M. genitalium infection also increases risk for miscarriage, which is the loss of a pregnancy in the first 20 weeks.

How is M. genitalium diagnosed? While there are tests for M. genitalium, so far, none of them has been approved by the FDA. However, it seems probable that an M. genitalium test will be approved by FDA in the future, making it easier to confirm this bacteria as the cause of a patient’s symptoms and enabling proper treatment.

What is proper treatment, though? More testing needs to be done, but at this time it seems that moxifloxacin is the most effective cure for M. genitalium — but without good diagnostic tests, many doctors might not know to prescribe it. Instead, a health care provider might treat an infection based on symptoms. But, although genital mycoplasma symptoms might mimic those of gonorrhea, treatment with ceftriaxone (the recommended treatment for gonorrhea) won’t have any effect on M. genitalium. Ceftriaxone kills the bacteria that cause gonorrhea by destroying their cell walls — but M. genitalium doesn’t even have a cell wall!

Genital mycoplasma symptoms might also be confused with chlamydia, and drugs that cure chlamydia might kill M. genitalium as well. Azithromycin, which is the drug of choice for chlamydia, is thought to be reasonably effective against genital mycoplasmas, but it also seems that M. genitalium‘s resistance to this drug is on the rise, as cure rates have declined from 85 to 40 percent. Doxycycline, which is also given to cure chlamydia, only cures M. genitalium in 31 percent of cases.

If you have any of the symptoms discussed in this article, you can be tested for STDs at any Planned Parenthood health center. Because the CDC doesn’t have guidelines for screening M. genitalium, and because there is no FDA-approved test, PPAZ does not screen for it as part of their routine STD testing practices. However, if a patient has recurring symptoms that are suggestive of an M. genitalium infection, we might be able to identify it by a culture. We can also treat for M. genitalium empirically — i.e., based on symptoms — which is standard practice for many types of infections. You can also drop by to pick up condoms, which offer great protection against STDs like M. genitalium.

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