Mycoplasma genitalium

Mycoplasma genitalium is a small bacterium with no cell wall, so traditional methods of Gram stain and culture cannot be used to detect and identify it. Nucleic acid amplification testing (NAAT) is recommended for detection of this organism.

Prevalence in Australia

The prevalence of M. genitalium infection in Australia varies depending on the clinical setting and population being tested. Overall, it is estimated to be around 1% in young adults (18-27 years old), but can be significantly higher in specific populations like men who have sex with men (MSM). Prevalence is also higher in individuals presenting with nongonococcal urethritis (NGU) (15-25%) and PID (up to 15%).
Symptoms
- M. genitalium has become a well-recognised cause of sexually transmitted infections worldwide and has been shown to cause urethritis, cervicitis and pelvic inflammatory disease (PID).
- Asymptomatic infections can also occur, but the consequences are unclear.
Treatment
- Clinical Labs microbiologists recommend using standard resources such as the ASHM Health Treatment Guidelines and/or the Australian Therapeutic Guidelines: Antibiotic for determining whether treatment is required, and if so, which agents to use.
- If a macrolide susceptibility result cannot be obtained by NAAT, then the best treatment regimen will depend on individual patient factors such as the presence or absence of symptoms, the possibility of reinfection, treatment(s) received so far and persistence/recurrence of PCR positivity.
- Complicated infections may require specialist referral.
- It is reasonable to assume macrolide resistance is present in infections persisting after failure of azithromycin, particularly in men who have sex with men, where macrolide resistance exceeds 80% in most urban settings in Australia.
- Contact tracing is recommended for ongoing sex partners.
Test of Cure
- Perform test of cure 21 days after treatment is completed, and if symptoms persist or there is ongoing risk of reinfection.
- Testing earlier than 14 days may lead to false-positive results.
How to Order Mycoplasma genitalium Testing
Who to Test:
- Testing should be performed on patients with persistent or recurrent urethritis or cervicitis once chlamydia and gonorrhoea have been ruled out and symptoms persist despite therapy.
- Testing should also be performed on patients with PID or post-coital bleeding.
- Current sex partners of patients being treated for symptomatic M. genitalium infection should also be tested, even if they are asymptomatic.
- Clinicians should not routinely screen for M. genitalium in asymptomatic individuals.
Request Form Instructions:
- Complete the Clinical Labs General Pathology request form, listing the required tests.
- To order Mycoplasma genitalium, please specify M genitalium PCR and macrolide resistance test.
Clinical Notes:
- Please provide adequate clinical details, including STI risk factors (if relevant), to assist with the processing of the samples and interpretation of results in our microbiology laboratory.
Specimen Details:
- Two dry swabs are required, one for PCR testing and one for macrolide resistance testing.
- Alternatively, a first-pass urine sample is also acceptable.
- Molecular tests are required to identify this organism and are approved for use on urine, endocervical, vaginal and urethral swabs.
- Throat swabs are not recommended, as pharyngeal infection is uncommon.
- Note: Vaginal swabs are more sensitive than FPU samples in female patients.
Test Cost:
- Bulk-billed, subject to Medicare eligibility criteria.
Additional Resources:
- STI Doctor Brochure
- STI Patient Brochure