What Is Mycoplasma Genitalium?

Mgen is a common bacteria linked to sexually transmitted infections

Mycoplasma genitalium (Mgen) is a type of bacteria that is sexually transmitted. In females, it can cause vaginal itching, burning with urination, and bleeding of the skin around the vagina. In males, it can cause urethral discharge or burning with urination.

Mgen 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.

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What Causes an Mgen Infection?

Genital mycoplasma, also called Mgen, is a bacteria that can infect the human reproductive organs, including the penis and vagina. It can also infect the rectum. Mgen is transmitted through unprotected vaginal or anal sex.

Mgen is a common sexually transmitted infection. According to some estimates, up to 1% of people in developed countries are infected with Mgen. In developing countries, the incidence may be as high as 4%. Anyone can get Mgen, but it is more common in sex workers and men who have sex with men than it is in other groups.

Mycoplasma Genitalium Symptoms

By and large, most cases of Mgen don't cause symptoms. If symptoms appear, they are primarily nonspecific and easily mistaken for other sexually transmitted infections (STIs) such as chlamydia and gonorrhea.

Mycoplasma genitalium symptoms also differ significantly in women and men.

Mgen Symptoms in Women
  • Vaginal itching

  • Burning with urination

  • Pain during intercourse

  • Bleeding between periods or after sex

  • With BV, a fishy odor after sex and changes in vaginal discharge

Mgen Symptoms in Men
  • Urethral discharge

  • Burning with urination

Mgen is the next most common cause of NGU in men behind chlamydia.

Mgen Complications

Mgen can cause complications in both men and women. These can include:

  • Urethritis: An inflammation of the urethra, which is the tube that carries urine out of the body. People with this condition may experience pain with urination.
  • Cervicitis: Females with this condition experience inflammation and irritation of the cervix, which is the bottom part of the uterus.
  • Pelvic inflammatory disease (PID): This condition affects the female reproductive organs and can make it hard to become pregnant.


There is no approved blood test for diagnosing Mgen. A nucleic acid amplification test (NAAT) is the standard test for a diagnosis.

A NAAT uses urine and swab samples from the urethra, opening of the penis, part of the cervix, or vagina, and produces results in 24 to 48 hours.

If a NAAT is unavailable at a certain clinic, a healthcare provider might go ahead and diagnose Mycoplasma genitalium simply based on the fact that urethritis or cervicitis is persistent or recurrent. Studies show that 40% of such cases in men and up to 30% in women are caused by Mgen.

Role in Guiding Treatment

Syndromi treatment is when all STI cases that fit a certain profile of symptoms are treated the same without knowing their actual cause.

Healthcare providers who diagnose Mycoplasma genitalium based on symptoms alone and treat it accordingly may be right, but not always. That means that some people may have an entirely different infection that warrants an entirely different treatment. Had the infection been confidently identified from the start, they could have started on the correct medication sooner.

NAAT is, therefore, the recommended testing method to diagnose a suspected case of Mgen. Your doctor can make specific treatment choices based on the results rather than trying something out based on an educated assumption.


Mycoplasma genitalium is typically treated with antibiotics.

In the past, the most common form of treatment was a single 1-gram (g) dose of azithromycin. But evidence has shown increased resistance to azithromycin in populations where it's used broadly. That means that the bacteria has mutated so that this drug is no longer effective.

Today, Mgen from a patient is tested to see whether or not the bacteria has mutated into a variant that is resistant to azithromycin. Results of that testing dictate the recommended treatment:

  • Mgen has not mutated: 100 milligrams (mg) of doxycycline two times a day for seven days, followed by an initial 1 gram dose of azithromycin, then 500 milligrams of azithromycin daily for the next three days
  • Mgen has mutated: 100 milligrams of doxycycline two times a day for seven days, followed by 400 milligrams of moxifloxacin once daily for seven days

Preventing Mgen

Condoms are the best way to prevent Mgen, but it is still possible to get infected even if you use one. Once you have been diagnosed with the condition, it is important to avoid having sex for at least 7 days after you begin treatment. This will help prevent you from passing the infection on to someone else. 

Frequently Asked Questions

  • Can you have mycoplasma genitalium for years?

    Yes. Because most people do not develop symptoms, it is possible to carry Mgen for years without knowing you have it. If you remain symptom-free, the infection may eventually resolve on its own, but it will be possible to transmit the bacteria during the time you are infected.

  • Can you get Mycoplasma from kissing?

    No. Mgen can't be passed through kissing or casual contact such as hugging, sharing towels, or using a public toilet seat. 

  • Is Mycoplasma genitalium hard to cure?

    Mgen may be becoming more resistant to first-line antibiotics like azithromycin and moxifloxacin. For this reason, the CDC recommends treatment with two 7-day courses of two different antibiotics.

  • Does mycoplasma genitalium cause a smell?

    Some females with Mgen notice a fishy odor, which tends to be more prominent after sex.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Keane FE, Thomas BJ, Whitaker L, Renton A, Taylor-Robinson D. An association between non-gonococcal urethritis and bacterial vaginosis and the implications for patients and their sexual partners. Genitourin Med. 1997;73(5):373-377.

  2. British Medical Journal. Mycoplasma Genitalium: easy to detect, hard to treat.

  3. Horner PJ, Martin DH. Mycoplasma genitalium Infection in MenJ Infect Dis. 2017;216(suppl_2):S396-S405. doi:10.1093/infdis/jix145

  4. Centers for Disease Control and Prevention. Sexually transmitted infections treatment guidelines.

  5. Bradshaw CS, Jensen JS, Tabrizi SN, et al. Azithromycin failure in Mycoplasma genitalium urethritis. Emerging Infect Dis. 2006;12(7):1149-1152. doi:10.3201/eid1207.051558

  6. Centers for Disease Control and Prevention. Mycoplasma genitalium.

Additional Reading

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.