Mycoplasma genitalium – CDC Detailed Fact Sheet
What is Mycoplasma genitalium?
Mycoplasma genitalium (or Mgen) is a sexually transmitted bacterium that can cause reproductive tract infections of the penile urethra or cervix. Mgen causes symptomatic and asymptomatic urethritis. It may also play a role in cervicitis, pelvic inflammatory disease (PID), preterm delivery, spontaneous abortion, and infertility.
How common is Mgen?
The 2017-2018 National Health and Nutrition Examination Survey estimates overall prevalence of urogenital Mgen to be 1.7% among people aged 14-59 years in the United States. The survey reported similar prevalence between males at 1.8% and females at 1.7%.1
Reported estimates of Mgen prevalence among clinic-based populations are higher. Among men presenting with urethritis in select STI clinics, 28.7% were positive for Mgen.2 Among women presenting in an STI clinic in Seattle, 26% had an Mgen infection.3 A large U.S. prospective multicenter study of a nucleic acid amplification diagnostic test for Mgen including male and female patients seeking care in diverse geographic regions found overall prevalence to be 10.3%. In this study, Mgen was more common among people ages 15 to 24 years than in people ages 35 to 39 years. The risk for Mgen was higher in Black participants than White participants and higher in non-Hispanic than in Hispanic participants.4 A meta-analysis of Mgen prevalence among gay, bisexual, and other men who have sex with men (MSM) found that urethral (5.0%) and rectal (6.2%) Mgen infections were more common than pharyngeal infections (1.0%).5
How do people get Mgen?
Mgen spreads through vaginal and anal sex without a condom with someone who has the infection. Researchers are still determining whether sex partners can spread Mgen through oral sex. People treated for Mgen can get reinfected.
What are signs and symptoms of Mgen?
Mgen causes symptomatic and asymptomatic urethritis among men.
When present, the typical symptoms of Mgen- urethritis include:
- urethral pruritus, and
- purulent or mucopurulent urethral discharge.
On examination, urethral discharge is often present. However, the discharge may not be grossly evident, and urethral milking (placing pressure along the length of the penis to express discharge) may be necessary for detection.
Among women, Mgen may cause cervicitis and PID, though individuals with cervicitis due to Mgen often are asymptomatic.
When present, symptoms associated with Mgen cervicitis include:
- vaginal discharge,
- vaginal itching,
- dysuria, and
- pelvic discomfort.
Clinical findings associated with cervicitis include purulent or mucopurulent cervical discharge and cervical friability. Vaginal wet smear or cervical fluid Gram stain may show elevated numbers of polymorphonuclear leukocyte cells.
Symptoms of PID due to Mgen may include:
- mild to severe pelvic pain,
- abdominal pain,
- abnormal vaginal discharge, and/or
Similarly, people may have asymptomatic Mgen in the pharynx. However, no evidence exists of it causing oropharyngeal symptoms or systemic disease. At this time, more research is needed to determine whether oral sex can spread Mgen.
What are the complications of Mgen infection?
Mgen is consistently associated with urethritis in cisgender males. However, there is not enough data to implicate Mgen infection with adverse reproductive sequelae (e.g., epididymitis, prostatitis, or infertility). The consequences of asymptomatic infection with Mgen among cisgender men are unknown.
While Mgen is associated with cases of PID, there are conflicting data regarding the strength of the association.9, 11 There are no clinical trials examining treatment of Mgen and prevention of PID. In vitro inoculation of Mgen into fallopian tube tissue causes damage to cilia, and Mgen is more common among cisgender women with infertility. However, data are conflicting regarding the association between Mgen and tubal factor infertility. Data are also limited regarding the association of Mgen with ectopic pregnancy or preterm delivery.
How should healthcare providers diagnose Mgen?
Nucleic acid amplification testing (NAAT) is the preferred method of detection for Mgen. Currently there are two FDA-approved NAATs.
To diagnose Mgen in men using NAAT, urine samples are the optimal specimen. For females, urine or cervical/vaginal swab samples are acceptable, but the preferred specimen types are vaginal swabs.12 Several commercial laboratories in the U.S. have laboratory-developed tests which also utilize nucleic acid amplification. There are not published data on the sensitivity and specificity of these tests compared to FDA-approved NAATs.
Mgen is an extremely slow growing organism. Culture can take up to six months and only a few research settings in the U.S. have the technical capability to culture Mgen.13
Who should receive Mgen testing?
People with recurrent urethritis and cervicitis resulting from treatment failure of initial therapy should receive Mgen testing. Also consider testing people with PID.
CDC does not recommend screening for Mgen in people who are asymptomatic. However, sex partners of patients with symptomatic Mgen infection should receive testing. Those with positive test results should receive treatment with antibiotics to possibly reduce the risk for reinfection. If testing the partner is not possible, healthcare providers should prescribe treatment to the partner with the same antibiotics that were prescribed to the patient.
How should healthcare providers treat Mgen?
The recommended treatment for all cases of Mgen is a two-step therapy with doxycycline, followed by an additional agent (either moxifloxacin or azithromycin). Although cure rates with doxycycline monotherapy are low, using doxycycline as the initial agent may lower Mgen organism load and facilitate organism clearance.
For cases occurring in pregnancy, please consult the STD Clinical Consultation Network for treatment recommendations.
How common are Mgen antibiotic resistance and treatment failure?
Mgen treatment failures can occur when using doxycycline, azithromycin, and moxifloxacin. Microbiologic cure rates are poor with either doxycycline or azithromycin monotherapy (~50% or less). Microbiologic cure rates for moxifloxacin were initially high (close to 100%) but have declined to 89% in studies conducted from 2010-2017.14
2 Bachmann LH, Kirkcaldy RD, Geisler WM, et al. Prevalence of Mycoplasma genitalium infection, antimicrobial resistance mutations and symptom resolution following treatment of urethritis. Clin Infect Dis 2020; 71:e624–e632:ciaa293. PMID: 32185385.
3 Khosropour CM, Jensen JS, Soge OO, et al. High prevalence of vaginal and rectal Mycoplasma genitalium macrolide resistance among female sexually transmitted disease clinic patients in Seattle, Washington. Sex Transm Dis 2020; 47:321–325.
4 Manhart LE, Gaydos CA, Taylor SN, et al. Characteristics of Mycoplasma genitalium Urogenital Infections in a Diverse Patient Sample from the United States: Results from the Aptima Mycoplasma genitalium Evaluation Study (AMES). J Clin Microbiol. 2020;58(7):e00165-20.
5 Latimer RL, Shilling HS, Vodstrcil LA, et al. Prevalence of Mycoplasma genitalium by anatomical site in men who have sex with men: A systematic review and meta-analysis. Sex Transm Infect 2020; 96:563–570.
6 Ong JJ, Aung E, Read TRH, et al. Clinical characteristics of anorectal Mycoplasma genitalium infection and microbial cure in men who have sex with men. Sex Transm Dis 2018Aug;45(8):522–526. doi: 10.1097/OLQ.0000000000000793. PMID:29465653.
7 Read TR, Fairley CK, Tabrizi SN, Bissessor M, Vodstrcil L, Chow EP, et al. Azithromycin 1.5g over 5 days compared to 1g single dose in urethral Mycoplasma genitalium: impact on treatment outcome and resistance. Clin Infect Dis. 2017 Feb 01;64(3):250-6.
9 Cina M, Baumann L, Egli-Gany D, Halbeisen FS, Ali H, Scott P, et al. Mycoplasma genitalium incidence, persistence, concordance between partners and progression: systematic review and meta-analysis. Sex Transm Infect. 2019 Aug;95(5):328-35
10 Baumann L, Cina M, Egli-Gany D, Goutaki M, Halbeisen FS, Lohrer GR, Ali H, Scott P, Low N. Prevalence of Mycoplasma genitalium in different population groups: systematic review and meta-analysis. Sex Transm Infect. 2018 Jun;94(4):255-262. doi: 10.1136/sextrans-2017-053384. Epub 2018 Feb 9. PMID: 29440466; PMCID: PMC5969327.
12 Van Der Pol B, Waites KB, Xiao L, Taylor SN, Rao A, Nye M, et al. Mycoplasma genitalium detection in urogenital specimens from symptomatic and asymptomatic men and women by use of the cobas TV/MG Test. J Clin Microbiol. 2020 May 26;58(6).
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