Mycoplasma genitalium

Mycoplasma genitalium (often called Mgen for short) is a common sexually transmitted infection. Although it was discovered in 1981, it is still considered a relatively new infection, and our understanding of this infection has only recently begun to get better with availability of reliable molecular diagnostic technology.

At a glance

Symptoms are very similar to Chlamydia, Gonorrhoea & Trichomonas.

See specific symptoms >

Mgen is a sexually transmitted infection, typically caused by unprotected sex.

See specific causes >

Due to low rates of Mgen testing, precise statistics are not available.

We’re looking further into this.

Testing & Treatment
Whilst testing is straightforward, treatment requires caution when dealing with this antibiotic resistant STI.

Learn more >


What are the symptoms of Mycoplasma genitalium in Men?

  • No symptoms
  • Discomfort or a change in sensation (complaining “it doesn’t feel right”)
  • Inflammation of the foreskin or penis
  • Inflammation or discharge from the back passage (Proctitis)
  • Irritation in water pipe
  • Pain when passing urine (Dysuria)
  • Pus-like discharge from urethra
  • Pain on ejaculation

What are the symptoms of Mycoplasma genitalium in Women?

The symptoms women experience may depend on the area of the genitalia that is affected by the infection.

Inflammation of the Cervix leads to:

  • Unusual or abnormal vaginal discharge
  • Bleeding after sex
  • Bleeding between periods
  • Pain during sexual contact

Inflammation of the Urethra leads to:

  • Dysuria

Inflammation of the Endometrium leads to:

  • Lower abdominal pain
  • Pelvic pain
  • Referred back pain

When do symptoms begin to occur?

The time interval between exposure and the development of symptoms can be variable. Symptoms are usually identified 1-3 weeks after the exposure. Many patients can have this infection for years before the symptoms develop, and a correct diagnosis is made.

Can I have Mycoplasma genitalium without knowing it? 

Yes. Most people do not experience any symptoms with Mycoplasma genitalium. Some people may be infected for years without knowing it.

Furthermore, testing for Mycoplasma genitalium has only begun recently in the UK. Thus, it is possible that those diagnosed with NSU, Epididymitis, Epididymo-Orchitis and Pelvic Inflammatory Disease (PID) may in fact have had Mycoplasma G. and may be at risk of recurrence.

Could the symptoms be of another STI? 

Yes. Symptoms such as pain on passing urine, unusual discharge and pelvic pain can also be symptoms of other STIs including:

  • Chlamydia
  • Gonorrhoea
  • Trichomoniasis

It is extremely important to get tested regularly, especially if you are showing symptoms or if you are concerned about your sexual health.


Because this is a relatively new infection, the true range of complications is not yet well established. The known complications include:

In Men: Epididymitis or Epididymo-orchitis

Mycoplasma genitalium can cause inflammation of the testicles and epididymis (the tubes carrying sperm from the testicles). This can be very painful but is easily treatable with antibiotics.

If the infection is left untreated, then there is a risk of becoming infertile.

In Women: Pelvic Inflammatory Disease (PID)

When Mycoplasma genitalium spreads to the womb, ovaries and/or fallopian tubes, there is a chance of getting PID. It is important to note that one may have PID without having any identifiable cause like an STI.

Fortunately, this condition can be treated with a course of antibiotics and if seen early enough, further complications can be avoided. This may include:

  • Difficulty in getting pregnant (which may progress to infertility)
  • Persistent pelvic pain
  • Greater risk of ectopic pregnancy (i.e. when a fertilised egg is implanted outside of the womb)

In Pregnant Women

Mycoplasma genitalium has been associated with miscarriage, stillbirth and premature birth in pregnant women. It may also be possible to pass Mycoplasma genitalium to your baby during birth.

It is thought that having Mycoplasma genitalium makes it easier to transmit or contract other sexually transmitted infections such as HIV.


These illustrations show the anatomical sites where the symptoms of Mgen are experienced.


How do I get Mycoplasma genitalium?

  • Unprotected vaginal sex
  • Unprotected anal sex
  • Unprotected oral sex (though this is thought to be less common)

There is no evidence that Mycoplasma genitalium can be spread from:

  • Toilet seats
  • Crockery
  • Kissing

Can I get Mycoplasma genitalium even if I wear a condom?

Condoms offer a high level of protection against Mycoplasma genitalium infection. It is important that condoms are used correctly during sexual contact, and have not split.

Who is most at risk of contracting Mycoplasma genitalium?

  • People who engage in unprotected vaginal, anal and oral sex
  • Genital to genital contact, not necessarily penetration
  • People who have had a greater number of sexual partners
  • People who have/already had another STI
  • Those with a partner who has Mycoplasma Genitalium
  • Smokers (significance not known)

Can I pass Mycoplasma genitalium onto my child?

It is currently unclear whether you can pass Mycoplasma genitalium to the fetus in utero. However, it is possible to pass the infection to an infant during childbirth. This can lead to premature birth, stillbirth and miscarriage [read more about symptoms here].

If you test positive for Mycoplasma genitalium and you think you may be pregnant, you must discuss this with your clinician as not all antibiotics used to treat this infection are safe to use during pregnancy.

How can I prevent getting Mycoplasma genitalium?

  • Practice safe sex
  • You and your new partner get tested before having unprotected sex


This is a RT-PCR test which means that the smallest amount of Mycoplasma genitalium DNA can be found in a good quality sample.  


Window Period

5 days after exposure

Sample required for men

For men: urine sample (please don’t urinate 1-2 hours before your appointment)

For women: (self-taken) high vaginal swab

Time for test results

Within 4 working days 

Cost of test

£130 (or £80 if taken with another test)

Do I need a test for Mycoplasma genitalium?

Testing for Mycoplasma is recommended when you have symptoms which can be caused by Mycoplasma Genitalium. This allows a clear diagnosis to be made and ensures the correct antibiotics are prescribed.

We also recommend this test if you may have been exposed to this infection and feel anxious about passing it to your regular or new partner.

Currently, BASHH guidelines do not recommend this test on a routine basis if you do not have any symptoms. This is due to limited availability and high cost of this test in the NHS.

When should I get tested for Mycoplasma Genitalium?

If you are experiencing symptoms of Mycoplasma genitalium or your partner has tested positive for Mycoplasma, please get tested without delay. Otherwise, we recommend waiting 5 days after sexual contact to get a Mycoplasma genitalium test.

Do I need a physical examination when getting tested?

We will only conduct a physical examination with your informed consent. Those with symptoms are recommended an examination with a male or female (as you prefer) clinician.

What strains of Mycoplasma are tested?

There are 18 different species of Mycoplasmas which can infect humans, of which only 4 species infect the genital area. Of these, Mycoplasma Genitalium is the only species that is considered to be sexually transmitted.

At Clarewell Clinics, we only test for Mycoplasma genitalium, which is the only sexually transmitted member of the Mycoplasma family.

We can also test for Mycoplasma Hominis in certain situations. However, this is not recommended on a routine screen.

What happens if my Mycoplasma genitalium test is positive?

If you test positive for Mycoplasma genitalium, we will recommend a test to check for antibiotic resistance in your sample (i.e. a Macrolide Resistance test). This is to determine the course of oral antibiotics to be given for the effective treatment of your infection.

We will also discuss what a positive result means for you and how to ensure you don’t pass it on to your partner.


Unlike Chlamydia, for example, Mycoplasma genitalium is a antibiotic resistant STI. This means that you can take a course of antibiotics and the infection fails to clear.

Considering the length of time you need to abstain from sexual intercourse (5 weeks) and to provide the most effective chance of cure, we utilise a Macrolide Resistance test to understand which type of antibiotic will be most effective. This will be followed by a test of cure in 5 weeks time to ensure you are cured of the infection.

Method of treatment

Oral antibiotics


Length of Treatment:

from 10 days (this may vary upon gender and antibiotic resistance)


Further actions:

  1. Abstain from sexual intercourse for 7 days, after beginning treatment
  2. Test & treat your partner(s)
  3. Re-test for Mycoplasma genitalium in 5 weeks

Cost of treatment

£250 (includes resistance test to determine the right course of antibiotics + test of cure in 5 weeks time to ensure the infection has gone).

Alternatively, we can refer you to the NHS.

Can Mycoplasma genitalium be treated?

Yes, Mycoplasma genitalium can be treated. Sometimes it may require some additional antibiotics to achieve the cure.

What is the treatment for Mycoplasma genitalium?

The treatment will involve a course of oral antibiotics. The choice and duration of antibiotics depends on your symptoms and signs, information from your Mycoplasma genitalium drug resistance test and the outcome of antibiotics you may have already had.

How long does it take for treatment to work?

Most patients will begin to notice improvement after a few days of taking treatment, and should have complete resolution of their symptoms by the time they have finished the course of antibiotics.

How effective is the treatment for Mycoplasma genitalium?

Treatment of Mycoplasma Genitalium infection is complex as the success rate of treatment can vary from 40% and 100%. This is because Mycoplasma Genitalium doesn’t have a cell wall which is what common antibiotics attack to resolve the infection.

If your symptoms do not resolve completely or you have a positive Mycoplasma Genitalium test result 5 weeks after beginning treatment, then we consider the treatment to have failed.

A Macrolide Resistance test (to look for resistance of the infection to antibiotics) can help in ensuring successful treatment of the infection. This will be discussed during your appointment.

What would cause my treatment for Mycoplasma genitalium to fail?

  • if you have got an infection with a resistant type of Mycoplasma Genitalium (most common)
  • if you develop antibiotic resistance while taking the antibiotics
  • if you are not able to take the antibiotics as prescribed (miss one or more tablets)
  • if you vomit or have a loose motion soon after taking the antibiotics (this can reduce the level of antibiotics in your blood and tissues to ineffective levels)
  • inadequate dose of antibiotics
  • if you have sexual contact with your infected partner before their infection has been properly treated

Does my partner need treatment?

Yes, your current partner(s) will need to get tested and receive treatment. All partners since your last negative Mycoplasma Genitalium test, if you had one before, need to be tested.

Can I begin treatment before receiving my test results?

It is vital that the results of the Mycoplasma Genitalium PCR test, and the result of the Macrolide Resistance test for antimicrobial resistance are available before starting a course of antibiotics unless you have symptoms suggestive of PID or epididymo-orchitis.

Having this information reduces the risk of treatment failure and helps to avoid antibiotics with greater side effects where possible.

However, when it is necessary to start antibiotics without waiting for test results, it is important to have appropriate specimens taken before any treatment is commenced. This helps to confirm the diagnosis, detect other infections that may require separate treatment, and serve as a baseline for a repeat Mycoplasma test 5 weeks later as a test of cure.

How long do I have to wait before having sex again?

Ideally you should avoid any sexual contact until your test of cure for Mycoplasma Genitalium 5 weeks later is negative. This prevents transmission of infection to the partner if your infection is not yet cleared (treatment failure rate can be as high as 50%).

If 5 weeks is a too long a period to abstain for you, then you must certainly avoid any sexual contact for at least 10 days from the start of your treatment. This is to ensure that your infection is properly treated and you do not get re-infected in this period. If your partner has received treatment after you, then it must be 10 days after their treatment has started.

What happens if I don’t get treated?

Mycoplasma Genitalium can be a chronic infection and remain infectious for many years.

If you do not have symptoms at the time of diagnosis, you may develop symptoms in the following weeks, sometimes years later from diagnosis. Women can develop cervicitis and Pelvic Inflammatory Disease (PID) with risk of reduced fertility and men can develop inflammation of testes and their tubes (epididymo-orchitis).

Furthermore, you may risk infecting your partner if you do not receive treatment.

Presence of having an untreated STI, including Mycoplasma Genitalium, increases the risk of acquiring HIV.

If left untreated in pregnancy, there is some evidence to suggest that Mycoplasma can cause preterm birth.

In some cases, the infection may resolve by itself in due course in absence of any treatment.

Page reviewed by Dr. Manoj Malu (Clinical Director)

Last reviewed date: 3 March 2020
Next review due: 3 March 2023

Whilst this content is written and reviewed by sexual health specialists, it is for general guidance only. It is not intended to replace the advice of your clinician.

References & Further Reading

If you think you may have Mycoplasma genitalium

It is important to refer to a healthcare provider as soon as possible. Our experience combined with timely detection can help put you on the right track without delay and avoid complications in the future.

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