Is Mycoplasma genitalium an STI?
Yes, Mycoplasma genitalium is definitively a sexually transmitted infection (STI). 1, 2
Transmission and Recognition
M. genitalium is transmitted through sexual contact and is now well-established as an emerging STI that has gained recognition over the past three decades 3, 4. The bacterium spreads through:
- Vaginal intercourse - the primary transmission route in heterosexual populations
- Anal intercourse - particularly common among men who have sex with men (MSM)
- Sexual contact with infected partners 2
While M. genitalium was first isolated in 1981, its classification as a sexually transmitted infection was not firmly established until the early 2000s 2. It is now recognized globally as a frequent cause of urogenital infections transmitted through sexual activity.
Clinical Significance as an STI
M. genitalium causes several sexually transmitted syndromes:
In males:
- Urethritis (both gonococcal and non-gonococcal) 5, 1
- Epididymitis 1
- Proctitis 1
- Often asymptomatic, making detection challenging 4
In females:
- Cervicitis 1, 4
- Pelvic inflammatory disease (PID) 1, 4
- Potential complications including infertility and adverse pregnancy outcomes 1, 3
- May present with nonspecific symptoms like dysuria, vaginal discharge, or pelvic pain 4
Treatment Considerations
The CDC guidelines specifically address M. genitalium in the context of STI treatment, noting that infections with M. genitalium respond better to azithromycin than doxycycline 5. Current recommendations include two-step treatment with doxycycline followed by either azithromycin or moxifloxacin, with resistance-guided therapy preferred when available 1.
Critical caveat: M. genitalium has developed significant antimicrobial resistance, earning it the designation as a "new STI superbug" in media reports 3. This makes it a particularly challenging STI to manage clinically 6.
Testing Recommendations
Testing should be targeted rather than universal 1:
- Persistent male urethritis
- Cervicitis and proctitis
- Pelvic inflammatory disease (consider testing)
- Sexual contacts of patients with confirmed M. genitalium
- Not recommended for asymptomatic patients, including pregnant individuals without exposure history 1