Mycoplasma genitalium
M. genitalium | M. gen |
Overview
- Our understanding of M. genitalium is rapidly evolving and so some recommendations are practical and likely to change as more evidence emerges
- Established cause of urethritis, cervicitis and PID and associated with preterm delivery and miscarriage(1, 2)
- Azithromycin (macrolide) resistance is common, particularly in MSM(3)
- More laboratories now offer testing and some tests report macrolide resistance
- Asymptomatic anorectal infection in MSM is common but the significance is unknown and asymptomatic screening is not currently recommended.
Cause
Mycoplasma genitalium
Clinical presentation
Further studies continuing to elucidate role in disease causation.
Diagnosis
| Diagnosis in males |
|---|
| Test | Site/Specimen | Consideration |
|---|
| NAAT* |
FPU |
n/a |
NAAT – Nucleic Acid Amplification Test
FPU – First pass urine |
| Diagnosis in females |
|---|
| Test | Site/Specimen | Consideration |
|---|
| NAAT |
Endocervical swab |
|
| NAAT |
Vaginal swab (clinician or self-collected) |
|
| NAAT |
FPU |
Not as sensitive as vaginal swab |
*NAAT – Nucleic Acid Amplification Test - some also detect macrolide resistance which will guide choice of therapy.
FPU – First pass urine |
Specimen collection
Clinician collected for NAAT/culture/microscopy
Urethral swabs for microscopy should be collected when the patient has not urinated for at least 1 hour and only if the patient has frank urethral discharge. Squeeze the urethra to express the discharge and collect on urethral swab. It is not necessary to insert the swab into the urethra.
Rectal swabs should be collected by inserting a sterile swab 2-4cms into the anal canal and moving the swab gently side to side for 10-20 seconds.
Pharyngeal swabs should be collected from the tonsils and oropharynx.
High vaginal swab of vaginal discharge smeared onto a glass slide, air dried and sent for microscopy. Swab inserted into transport medium for culture.
Self-collection of samples for NAAT testing
Vaginal swab: instruct the patient to insert the swab into the vagina like a tampon and then remove and place into the transport tube.
Rectal swab: instruct the patient to insert the swab into the anal canal 2-4cms and then remove and place into the transport tube.
FPU (First pass urine): Collect approximately 20 ml (1/3 of the standard urine jar) of the first part of the urine stream in a specimen jar at the time you are consulting the patient. The patient does not need to have held their urine for more than 20 minutes prior to specimen collection. A midstream urine (MSU) or early morning specimen (i.e. first void urine) are not required for NAAT.
Click here for information on how to describe self-collection technique to a patient.
Investigations
- Throat swabs are not recommended as pharyngeal infection is uncommon.
- NAAT testing for Mycoplasma genitalium is available in reference laboratories and in some private laboratories. Some tests can detect macrolide resistance mutations which can guide choice of therapy.
Special considerations
Screening asymptomatic people for M. genitalium is not recommended. Only test those with symptoms and their contacts.
Management
Treating a macrolide-susceptible M. genitalium infection with azithromycin will result in treatment failure and macrolide resistance in about 10% of infections.
Macrolide resistance is likely to be present in at least half of infections in Australian cities, based on studies from the eastern states. At one centre resistance was present in 50% of infections in heterosexuals and 80% in MSM. Resistance to fluoroquinolones is present in 10 – 15% of infections.
Doxycycline is ineffective in two-thirds of infections but will lower bacterial load in most cases, increasing the likelihood of cure with a subsequent antibiotic.
Pre-treating M. genitalium infections with doxycycline 100mg bd for one week and then treating susceptible infections with azithromycin and macrolide-resistant infections with a fluoroquinolone eradicated >90% of infections.(4)
Without access to resistance testing, it is reasonable to assume macrolide resistance in infections persisting after failure of azithromycin and in MSM.(3)
| Principal Treatment Options |
|---|
| Situation | Recommended | Alternative |
|---|
| M. genitalium infection known or suspected to be macrolide-susceptible |
Doxycycline 100mg bd for 7 days
followed by
Azithromycin 1g stat then 500mg daily for three days (total 2.5g)*
|
Doxycycline 100mg bd for 7 days
followed by
Azithromycin 1g single dose* |
| M. genitalium infection known or suspected to be macrolide-resistant |
Doxycycline 100mg bd for 7 days
followed by
Moxifloxacin 400mg daily for 7 days
|
|
| Pelvic inflammatory disease due to M.genitalium |
Moxifloxacin 400mg daily for 14 days** |
|
*It is not known to what extent the improved outcomes resulting from the use of doxycycline followed by 2.5g azithromycin are due to this dose of azithromycin, rather than simply the pre-treatment with doxycycline. The higher dose of azithromycin requires a private prescription.
**M. genitalium results are often received about a week after PID treatment has begun. After a good response to treatment it may be reasonable to shorten the course of moxifloxacin to ten days, due to the cost and potential toxicity of this drug, however this has not been studied.
Moxifloxacin requires a private prescription, cannot be used in pregnancy, and is expensive and is associated with diarrhoea, occasional tendinopathy and rare neurological and cardiac events.
Other immediate management
- Advise no condomless sex until tested for cure (14 days after completion of treatment).
- Advise no sex with untested previous sexual partners.
- Provide patient with factsheet
- M. genitalium is not a notifiable condition.
Special treatment situations
Special considerations
If moxifloxacin fails or cannot be used, seek specialist advice.
Contact tracing
- In heterosexuals the risk of PID and reproductive complications suggests a greater need to trace, test and treat infected contacts. The time period for contact tracing is unknown.
- Asymptomatic infection and macrolide resistance are more common in MSM and there is only limited evidence that this is harmful. As moxifloxacin will probably be required for treatment, contact tracing may be best confined to continuing partners of a symptomatic person.
See Australasian Contract Tracing Manual - Mycoplasma genitalium for more information.
Follow up
Test of Cure (TOC)
TOC by NAAT should be done at least 2 weeks after treatment is completed ie 4 weeks after commencing therapy.
References
- Jensen JS, Bradshaw C. Management of Mycoplasma genitalium infections - can we hit a moving target? BMC infectious diseases. 2015;15:343.
- Lis R, Rowhani-Rahbar A, Manhart LE. Mycoplasma genitalium infection and female reproductive tract disease: a meta-analysis. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2015;61(3):418-26.
- Read TRH F, CK, Tabrizi S, Bissessor M, Vodstrcil L, Chow EPF, Grant M, Danielewski J, Garland SM, Hocking JS, Chen MY, Bradshaw CS. Azithromycin 1.5g over five days compared to 1g single dose in urethral Mycoplasma genitalium: impact on treatment outcome and resistance Clinical Infectious Diseases. 2016.
- Read TRH, Fairley CK, JS J, Murray GL, Worthington K, Doyle M, et al. Improved outcomes following resistance-guided treatment of Mycoplasma genitalium infection. International Society for Sexually Transmitted Diseases Research; Rio de Janiero2017.