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Mycoplasma genitalium (Mgen)

Mycoplasma genitalium is a bacterial infection that is sexually transmitted.

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What is mycoplasma genitalium and how common is it?   

Mycoplasma genitalium (Mgen) is a type of bacteria that spreads through sexual contact. One to two percent of the general population are estimated to have the infection but most do not have any problems and clear Mgen infection without treatment. However, infection of the water passage (urethritis), the womb and fallopian tubes (pelvic inflammatory disease) and the back passage (rectum) can cause symptoms. Around 10-15% of men with discharge from the penis or pain passing urine will have Mgen, and around 5-10% of women with pelvic pain will test positive for this infection. 

How is mycoplasma genitalium transmitted? 

Mgen can be passed between people through: 

  • unprotected vaginal or anal sex
  • oral sex, mutual masturbation, and use of sex toys

It cannot be passed on through: 

  • sharing towels
  • baths and swimming pools
  • toilet seats
  • saunas and steam rooms

Currently there is no information on the timings of infection and developing symptoms.  

What are the symptoms of mycoplasma genitalium?   

Almost all Mgen infections are symptom free. Very occasionally people develop symptoms because of Mgen infection. These are different in people with a vagina and people with a penis.   

Mgen symptoms in people with a vagina can include:  

  • pain when weeing
  • unusual vaginal discharge
  • pain in the tummy or pelvis
  • pain during or after penetrative sex
  • irregular vaginal bleeding
  • discomfort or discharge from your bum if you have had anal sex

Complications can include infection in the womb and fallopian tubes (pelvic inflammatory disease), infection in the neck of the womb (cervicitis), and may be a cause of early labour and miscarriage in pregnant people however this link is not yet well understood.   

Mgen symptoms in people with a penis can include: 

  • discharge from the penis
  • pain when weeing
  • infection in the water passage (urethritis) or discomfort
  • discomfort or discharge from your bum if you have had anal sex
  • pain in the testicles

Complications can include inflammation of the testicles and epididymis.   

How is mycoplasma genitalium diagnosed?   

You will be offered testing for Mgen if:

  • you have inflammation of the urethra (water passage)
  • you have symptoms of an infection of the womb and fallopian tubes (pelvic inflammatory disease)
  • you are a current sexual partner of someone diagnosed with Mgen 

For people with a vagina, a swab is taken from inside the vagina either by a healthcare professional or by you, if you prefer.  

For people with a penis, a pee sample (urine) can be tested or a swab of discharge from the penis. There is no blood test to diagnose Mgen.  

Treatment may be offered to you on the day if you have symptoms and inflammation is seen under the microscope or if a current or recent sexual partner has been diagnosed with Mgen. The test results for Mgen may take up to 14 days to come back, but you will be informed by the clinic if the result of the test is positive. 

How is mycoplasma genitalium treated? 

Mycoplasma is a bacterial infection and it is treated with antibiotics. The length of treatment and type of antibiotic given depends on your infection, your medical history, and any antibiotic resistance in the bacteria itself.  

Are there any side effects to the treatment for mycoplasma genitalium? 

Mgen is commonly treated with a group of antibiotics called quinolones and treatment is free from sexual health clinics. These antibiotics are well tolerated but common side effects include reduced appetite, nausea, and bowel habit changes. In rare cases they can cause serious side effects including joint and tendon symptoms and mood changes. More details about the different side effects of the medication you have been prescribed can be found in the information leaflet in your treatment pack.    

What follow up is needed after treatment? 

You should not require repeat testing after your course of treatment is completed. You may be re-tested if you have persistent symptoms after completing treatment. Following successful treatment there is still a risk of reinfection with Mgen from untreated sexual partners. Our health advisers will discuss partner notification with you and can help with this.   

Other frequently asked questions (FAQs) about mycoplasma genitalium 

If you or one of your sexual partners have any of the symptoms of Mgen or if a current or recent sexual partner has been diagnosed with Mgen please come and request free testing. 

You can have Mgen and not have symptoms. It can be passed on from any form of sexual contact so it may be hard to pinpoint exactly when a person picked up the infection.   

Yes, Mgen can be transmitted through sexual activities, including oral sex, mutual masturbation and the sharing of sex toys. The risk of transmission can be reduced by using barriers, such as dental dams for oral sex, condoms on sex toys, and washing sex toys after use.

Many people who have Mgen do not experience any symptoms and many clear the infection without any treatment. If you have symptoms or are a sexual contact of someone with Mgen, visit a sexual health clinic for testing and potential treatment.   

No, Mycoplasma genitalium is in the same family of bacteria but they cause different infections.  

Your visits to a sexual health clinic are always confidential, and during your visit a member of the clinical team will ask you questions about your symptoms and sexual history. If you are experiencing symptoms, an examination will be offered with your consent. The nurse or doctor may take some samples using swabs, or they may ask you to provide a pee sample (urine). You can ask for a chaperone or bring someone with you to your appointment if this helps you feel more comfortable.  

Treatment may be offered to you on the day, and if your tests show any sexually transmitted infections the health adviser team will help you with partner notification. This can be done using software at the clinic that invites recent partners to seek testing without informing them of your visit. The tests for some infections, including Mgen can take up to 14 days to come back, so you will be phoned by the clinic if these are positive, or get a text message letting you know if they are negative.  

Mgen is sexually transmitted, so it is important that your current partner or partners are tested for this infection too. If they carry the infection, there is a risk you will be re-infected if you have sex with them before they have completed their treatment. We can help you tell any partners if you would prefer.  

Rarely, Mgen can spread from the neck of the womb to the womb and fallopian tubes. This is called pelvic inflammatory disease and may cause longer term problems with fertility. Mgen may also spread from the water passage (urethra) to the testicles, causing pain and swelling of the testicles called epididymo-orchitis, we do not know yet if this may cause long term problems with fertility   

 It is advised that the person with Mgen should not have sexual contact until 14 days after the start of treatment, and until symptoms have resolved.   

We advise you not to have any type of sex (with or without condoms) until you and any regular sexual partners have finished treatment and your symptoms have gone. 

Yes, you can. If you have had Mgen, it does not stop you from getting Mgen again. Using condoms for sex, washing sex toys after use or covering them with a condom and replacing it between partners, can all help reduce the chance of Mgen being transmitted.     

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