Mycoplasma genitalium (MG)

M. genitalium electron micrograph

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Electron micrograph depicting M. genitalium adhering to Vero cells.*

Emerging STI Superbug: Mycoplasma genitalium

  • M. genitalium (MG) is a recognised STI, treated syndromically, with clinical presentation similar to that of Chlamydia trachomatis. 1
  • Mutations in the 23S rRNA gene of M. genitalium have been linked with clinical treatment failure and high level in vitro macrolide resistance. 2
  • Macrolide resistance mediating mutations have been observed in 20-50% of cases in the UK, Denmark,Sweden, Australia, and Japan. 3
  • Resistance is already developing towards the second-line treatment moxifloxacin (fluoroquinolone).4


Treatment options are limited.
Inclusion of an antibiotic resistance test in your therapy algorithm will likely improve patient outcome.5

  • Omitting a macrolide resistance screen when testing for MG, may lead to inappropriate patient antimicrobial treatment.
  • Ineffective antimicrobial treatment can result in persistent infection and ultimate spread of MG which is antimicrobial resistant (AMR).
  • Diagnosis is recommended using nucleic acid amplification testing (NAAT) which includes an assessment of macrolide resistance.6
  • Screening for M. genitalium with a combination of detection and macrolide resistance mutations will provide much needed information to develop personalised antimicrobial treatments and improve patient outcome.6,7


M. genitalium General Information

  • MG was first identified in the 1980s 8 and is now a recognised sexually transmitted infection (STI), more prevalent than N. gonorrhoeae in many populations.9 MG is associated with 10–35% of non gonococcal urethritis (NGU),7,10 and as much as 45% of persistent/recurrent urethritis.6
  • MG is an extremely fastidious and slow growing organism,3 making nucleic acid amplification testing (NAAT) the only viable diagnostic.6,9 Treatment options are limited as mycoplasma lack a cell wall, thus are unaffected by many common antibiotics.9,10 Of additional concern is the apparent rapid rate of mutation of MG, resulting in an alarming increase in AMR in relatively short periods of time.3

Potential Health Risks

  • Most M. genitalium cases are asymptomatic, any associated symptoms are similar to those caused by other STI pathogens such as Chlamydia trachomatis.1
  • The presence of M. genitalium is associated with an increased risk of NGU10 and of acquiring HIV.12
  • Increased risk of cervictis, PID, preterm birth, spontaneous abortion and infertility in women.11


Improve patient management.
Test for macrolide resistance.


Download M. genitalium fact sheet



1. Manhart LE and Kay N. Mycoplasma genitalium: Is It a Sexually Transmitted Pathogen? Curr. Infect. Dis. Reps. 2010; 12(4):306-313.
2. Jensen JS. et al. Azithromycin Treatment Failure in Mycoplasma genitalium–Positive Patients with Nongonococcal Urethritis Is Associated with Induced Macrolide Resistance. Clin. Infect. Dis. 2008; 47(12): 1546-1553.
3. Jensen JS and Bradshaw C. Management of Mycoplasma genitalium infections – can we hit a moving target? BMC Infect. Dis. 2015; 15 :343.
4. Couldwell DL, Tagg KA, Jeoffreys NJ, Gilbert GL. Failure of moxifloxacin treatment in Mycoplasma genitalium infections due to macrolide and fluoroquinolone resistance. Int. J. STD AIDS. 2013 Oct;24(10):822-8.
5. Unemo, M. & Jensen, J.S. ‘Antimicrobial-resistant sexually transmitted infections: gonorrhoea and Mycoplasma genitalium’. 2016. Nat. Rev. Urol..268. Published online 10 Jan 2017. doi:10.1038/nrurol
6. Jensen, M Cusini, M Gomberg. 2016 European guideline on Mycoplasma genitalium infections.
7. Tabrizi SN et al. Multiplex Assay for Simultaneous Detection of Mycoplasma genitalium and Macrolide Resistance Using PlexZyme and PlexPrime Technology. PLoS ONE. 2016. 11(6): e0156740. doi:10.1371/journal.pone.0156740
8. Tully JG, Taylor Robinson D, Cole RM, Rose DL. A newly discovered mycoplasma in the human urogenital tract. Lancet. 1981; I: 1288–91.
9. Centers for Disease Control and Prevention, 2015 Sexually Transmitted Diseases Treatment Guidelines.
10.Taylor-Robinson D and Jensen JS. Mycoplasma genitalium: from Chrysalis to Multicolored Butterfly. Clin. Microbiol. Rev. 2011; 24(3): 498-514.
11. Lis R, Rowhani-Rahbar A, and Manhart LE. Mycoplasma genitalium Infection and Female Reproductive Tract Disease: A Meta-analysis. Clin. Infect. Dis. 2015; 61 (3): 418-426. doi: 10.1093/cid/civ312
12. Napierala Mavedzenge, S Weiss HA. Association of Mycoplasma genitalium and HIV infection: a systematic review and meta-analysis. AIDS. 2009; 23: 611–20.
* Electron micrograph depicting M. genitalium adhering to Vero cells. EM performed by Jens Blom from culture by Jørgen Skov Jensen, Statens Serum Institut.

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