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The STD Mycoplasma Genitalium Is Becoming a Problem

Doctors warn that it's already showing resistance to antibiotics.
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Health experts in the United Kingdom are warning the public about a little-known sexually transmitted infection that is on the rise—and may be becoming resistant to antibiotics.

First identified in the UK in the early 1980s, it’s called Mycoplasma genitalium (MG). It may affect 1 to 2 percent of the population, with rates slightly higher for women; it’s primarily spread through genital-to-genital contact—unprotected sex, in other words. A study in Australia showed that among women who’d had sexual contact with an MG-infected person, 48.2 percent were themselves infected. Among heterosexual men, the rate was 31.0 percent, and for men having sex with men (MSM), the rate was 41.7 percent.


In most cases, infections produce no symptoms. In men, however, it can inflame the urethra, the tube that carries urine from the bladder and out of the body, making urination painful. Women may experience inflammation of the womb and fallopian tubes. And while some research shows an association between MG infections and infertility, that link is far from settled.

The lack of symptoms can make an MG infection difficult to spot; though tests to detect it have recently been developed, infections can still be missed, or mistaken for other STIs. That’s one reason British Association of Sexual Health and HIV (BASHH) is encouraging testing for anyone with the kind of inflammation associated with MG.

The group recently unveiled a draft set of guidelines for combatting MG. It recommends testing only patients who show symptoms of possible infection, rather than a broader population. The standard treatment is a regimen of antibiotics.

But BASHH is also concerned that MG—like many other bacteria, including gonorrhea—is developing antibiotic resistance. Worldwide, MG has shown increasing resistance to one family of antibiotics, called macrolides. BASHH cites findings that in the UK, macrolide resistance is around 40 percent, though that statistic, the group cautions, may be high because most samples tested for resistance are those that haven’t responded to typical treatment.

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Increasing resistance is one reason this previously obscure bacteria is now getting more attention. “These new guidelines have been developed because we can't afford to continue with the approach we have followed for the past 15 years,” Paddy Horner, who helped write the guidelines, told the BBC, “as this will undoubtedly lead to a public health emergency with the emergence of MG as a superbug.”

In the United States, the Centers for Disease Control and Prevention listed Mycoplasma genitalium among its “emerging issues,” citing the bacteria’s increasing resistance to antibiotics. According to BASHH, antibiotic resistance rates for the US are similar to those in the UK: 40 to 50 percent of infections don’t initially respond to treatment. That’s higher than in Russia and Japan (less than 20 percent and 30-40 percent, respectively), but lower than New Zealand, Canada, and Australia, all of which have resistance rates higher than 50 percent. As the International Union against Sexually Transmitted Infections (IUSTI) pointed out in its 2016 guidelines, the problem is worldwide: Bacteria don’t abide by borders.

BASHH is calling on medical authorities to take a more serious look at the problem. That lack of urgency among healthcare providers is a global issue as well; one study of MG infections in the United States called it “the silent epidemic.” BASHH hopes to change that by drawing attention to the problem. In the meantime, luckily, protecting yourself means taking familiar precautions: Use condoms for sex with new and casual partners, and if you have symptoms of an STI, see your doctor.

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