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.
Mgen is a sexually transmitted infection, typically caused by unprotected sex.
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.
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:
Inflammation of the Endometrium leads to:
- Lower abdominal pain
- Pelvic pain
- Referred back ache
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:
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
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.
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
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
Length of Treatment:
from 10 days (this may vary upon gender and antibiotic resistance)
- Abstain from sexual intercourse for 7 days, after beginning treatment
- Test & treat your partner(s)
- Re-test for Mycoplasma genitalium in 5 weeks
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
- International Journal of Epidemiology: Epidemiology of Mycoplasma genitalium in British men and women aged 16–44 years: evidence from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)
- BMC Infectious Diseases: STI in times of PrEP: high prevalence of chlamydia, gonorrhea, and Mycoplasma genitalium at different anatomic sites in men who have sex with men in Germany
- Terrence Higgins Trust: Mycoplasma genitalium (Mgen)
- The Journal of Infectious Diseases: Mycoplasma genitalium Infection in Men | The Journal of Infectious Diseases
- NHS: New guidelines issued on the ‘STI most people have never heard of’
- Emerging Infectious Diseases: Symptoms, Sites, and Significance of Mycoplasma genitalium in Men Who Have Sex with Men
- Infection and Drug Resistance: Mycoplasma genitalium infections: current treatment options and resistance issues
- Germs: Prevalence of Mycoplasma genitalium and other sexually-transmitted pathogens among high-risk individuals in Greece
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.