Diagnosis and Treatment of Mycoplasma Genitalium

Common bacteria linked to STIs in women and men

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Mycoplasma genitalium (MG) bacteria is a sexually transmitted infection (STI). It can cause vaginal itching, burning with urination, and bleeding of the skin around the vagina in women, and urethral discharge or arthritic symptoms in men.

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Related Conditions

MG is the cause of several types of infections, including forms of bacterial vaginosis (BV) and non-gonococcal urethritis (NGU).

It has also been associated with pelvic inflammatory disease (PID) and implicated in other infections once attributed to other bacteria.

Symptoms

By and large, most cases of MG are asymptomatic. If symptoms do appear, they are largely nonspecific and easily mistaken for other STIs such as chlamydia and gonorrhea. MG symptoms also differ significantly in women and men.

Women's symptoms include:

  • Vaginal itching
  • Burning with urination
  • Pain during intercourse
  • Bleeding between periods or after sex
  • With bacterial vaginosis, a fishy odor after sex, and changes in vaginal discharge

Men may experience:

  • Urethral discharge
  • Burning with urination
  • Pain and swelling of the joints (arthritis)

MG is the most common cause of non-chlamydial NGU in men.

Challenges in Diagnosis

The main barrier to diagnosing MG is that there is no approved blood test to confirm infection. Direct diagnosis requires a bacterial culture, which takes up to six months to grow.

Doctors do have other ways to directly identify mycoplasm genitalium, but those tests are mostly reserved for research.

Because of this, MG is usually diagnosed presumptively. In other words, your doctor might diagnose MG as the cause of your symptoms after other options have been ruled out.

In fact, MG is present in most BV and NGU infections. According to the Centers for Disease Control and Prevention, between 15% and 20% of non-gonococcal urethritis cases are directly caused by MG.

MG is implicated in one out of every three cases of persistent or recurrent urethritis.

Mycoplasma can be detected in up to 30% of women with symptoms of cervical inflammation or infection.

Treatment

Mycoplasma genitalium is typically treated with antibiotics, most commonly a single 1 gram dose of azithromycin. While azithromycin is considered safe and effective, there's evidence of increasing resistance to the drug in populations where it's used broadly.

While other antibiotics may be substituted for azithromycin, doxycycline is considered less effective (albeit with a lower risk of resistance). An extended course of moxifloxacin has been shown to be very effective in some studies. However, shorter courses often are ineffective.

Treatment Problems

The presumption of MG in cases of NGU can lead to treatment failure, however. This can occur as a result of syndromic treatment of STIs, which is when all STIs are treated the same way, without identification of the cause.

This type of treatment can expose you to medications that may not work as well as the treatment your doctor would select if they knew what your specific infection was. In bacterial infections, the wrong antibiotic can lead to antibiotic-resistant bacteria.

Growing concerns about antibiotic-resistant gonorrhea have led to changes in the recommended treatment regimen over the past decade. The concern is that, in time, no treatments for this common STD will be reliable.

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  2. National Health Services. New guidelines issued on the 'STI most people have never heard of.' Updated July 11, 2018.

  3. Centers for Disease Control and Prevention. 2015 sexually transmitted diseases treatment guidelines. Updated June 4, 2015.

  4. Bradshaw CS, Jensen JS, Tabrizi SN, et al. Azithromycin failure in Mycoplasma genitalium urethritis. Emerging Infect Dis. 2006;12(7):1149-52. doi:10.3201/eid1207.051558

  5. Bradshaw CS, Jensen JS, Waites KB. New horizons in mycoplasma genitalium treatment. J Infect Dis. 2017;216(suppl_2):S412-S419. doi:10.1093/infdis/jix132

  6. Vincent LR, Jerse AE. Biological feasibility and importance of a gonorrhea vaccine for global public health. Vaccine. 2019;37(50):7419-7426. doi:10.1016/j.vaccine.2018.02.081

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