Mycoplasma Genitalium Partner Protocols + Treatment Failure
Treating Mycoplasma genitalium (Mgen) is harder than treating chlamydia or gonorrhea. The drug regimen is longer, resistance is increasingly common, and treatment failure is real (20-30% in some studies). Partner notification is critical but often messy.
If you're navigating Mgen — yourself, partner, or both — here's the practical playbook.
The short answer
- Partner treatment is essential — all sexual partners from past 60 days must be tested AND treated
- Resistance testing improves outcomes significantly when available
- Treatment failure is real (~20-30%) — have a plan
- Test of cure at 3-4 weeks is recommended
- Reinfection vs treatment failure can be hard to distinguish
Standard Mgen treatment review
CDC 2021 regimen (still current)
- First: Doxycycline 100 mg twice daily for 7 days
- Then: Moxifloxacin 400 mg daily for 7 days
OR if resistance testing available:
- Macrolide-susceptible: Doxycycline + azithromycin
- Macrolide-resistant: Doxycycline + moxifloxacin
See Mycoplasma genitalium overview.
The partner protocol
Who to notify
All sexual partners from past 60 days, including:
- Current partner(s)
- Recent past partners
- Casual/anonymous partners (when possible)
What partners need
- Testing — Mgen NAAT (not part of basic STI panels)
- Treatment — same regimen as you
- Re-test of cure if appropriate
- Coordinate treatment timing to prevent ping-pong reinfection
Expedited partner therapy (EPT)?
- Allowed in some states for chlamydia/gonorrhea
- Less established for Mgen
- Mgen-specific EPT is complicated by the 2-drug regimen and need for resistance testing
- Better to refer partners for full evaluation
Conversation script
"I tested positive for Mycoplasma genitalium — Mgen. It's a kind of STI. It's not in most basic panels but it's increasingly common. I need to be treated for 7 days with doxycycline then another 7 days with moxifloxacin. You should also get tested and treated. Can we both abstain from sex until we both finish treatment?"
Treatment failure — what it means
Failure rate
- 20-30% of patients have persistent or recurrent infection
- Higher with macrolide-resistant strains
- Higher with poor adherence
- Lower with appropriate resistance-guided treatment
How to know it's failure (not reinfection)
- Test of cure at 3-4 weeks post-treatment
- Positive = either treatment failure or reinfection
- Sequencing can sometimes distinguish (same strain = failure)
- New strain = reinfection
Common failure reasons
- Resistance to azithromycin (50-80% prevalence)
- Resistance to moxifloxacin (10-30% in some areas)
- Adherence issues
- Drug interactions reducing absorption
- Inadequate dosing
What to do when treatment fails
Step 1: Confirm failure
- Repeat NAAT
- Confirm symptoms
- Consider that it might be co-infection with another STI
Step 2: Resistance testing if available
- 23S rRNA mutation testing — for macrolide resistance
- ParC mutation testing — for fluoroquinolone resistance
- Send to specialty lab if local lab doesn't offer
Step 3: Different regimen
- Macrolide-resistant + moxifloxacin-naive: Doxycycline + moxifloxacin (extended)
- Both resistant: Pristinamycin (limited availability)
- All failures: Infectious disease consultation
Step 4: Re-evaluate partner status
- Has partner been treated?
- Has there been re-exposure?
- Is there a partner you didn't notify?
Resistance pattern by region
Macrolide resistance
- United States: 50-70% in major studies
- Australia/New Zealand: Very high (70-80%)
- Northern Europe: 30-50%
- Africa: Varies
Fluoroquinolone (moxifloxacin) resistance
- Rising rapidly in many regions
- Asia-Pacific: Particularly high (20-50%)
- United States: 10-20%
- Likely to increase without antibiotic stewardship
Knowing your local resistance pattern helps treatment selection.
After successful treatment
Test of cure
- Recommended at 3-4 weeks post-treatment
- Confirms cure
- Catches treatment failure early
Re-testing for reinfection
- At 3 months for general re-screening
- Earlier if new exposure
Sexual activity
- Abstain for 7 days after starting treatment AND until partner is treated
- After confirmed cure: can resume normal sexual activity
Special situations
Pregnancy
- Doxycycline contraindicated in pregnancy
- Azithromycin alone often fails (resistance)
- Moxifloxacin not first-line in pregnancy
- Specialist consultation usually needed
- Coordination of partner treatment + delivery planning
HIV+ patients
- Standard regimen, but higher failure rates
- Closer follow-up
- More aggressive partner treatment
Recurrent Mgen
- Refer to infectious disease specialist
- Confirm partner treatment is complete
- Test for resistant strains
- Consider:
- Pristinamycin (1 g 4 times daily for 10 days)
- Lefamulin (newer; limited data)
- Long-course doxycycline (some success)
Asymptomatic infection
- Routine asymptomatic Mgen screening NOT recommended by CDC
- Test if treatment failure suspected, partner notification, or specific clinical concern
- Asymptomatic carriers can transmit
Cost considerations
- Mgen NAAT: $150-300+ self-pay (varies by lab)
- Doxycycline: cheap (~$20 for course)
- Moxifloxacin: $100-300 (generic) per course
- Resistance testing: $200-500 per test
- May be covered by insurance if symptoms documented
Why Mgen is increasingly important
Public health concern
- Many infections missed
- Increasing resistance
- Linked to PID, infertility risk in women
- Linked to non-gonococcal urethritis in men
Personal health
- If you have persistent urethral or cervical symptoms, ask about Mgen
- If treatment for "chlamydia" doesn't resolve symptoms, ask about Mgen
- If your partner has been treated for Mgen, get tested
What to do if your partner says they have Mgen
- Get tested as soon as possible (Mgen NAAT, not basic panel)
- Get treated if positive — same regimen as them
- Abstain from sex until both completed treatment + cure
- Plan follow-up testing at 3-4 weeks
- Don't assume single course will work
Common questions
"Is Mgen always sexually transmitted?" Strong epidemiological evidence for sexual transmission. Some debate about whether it can be transmitted other ways (rare cases without clear sexual contact).
"Can I just take azithromycin and skip the 14-day course?" Not anymore — azithromycin alone has 50-80% failure rate in many places due to resistance.
"My doctor doesn't know about Mgen." Increasingly common. You can request testing specifically or seek out a sexual health specialist.
"How do I know if I have Mgen vs Mycoplasma hominis or Ureaplasma?" Specific NAAT testing distinguishes these. Mgen specifically is the well-validated pathogen.
"Will treatment failure cause permanent damage?" Often not, but persistent Mgen has been linked to PID, infertility, prostatitis — so getting cured matters.
Bottom line
Mgen treatment:
- Requires 14-day combination regimen (doxycycline then moxifloxacin)
- Has 20-30% failure rate without resistance testing
- Partner notification + treatment is essential
- Test of cure at 3-4 weeks confirms clearance
- Treatment failure needs specialist consultation
If you're in any of these scenarios, work closely with your provider, push for resistance testing when available, and be persistent about partner treatment coordination. Mgen is one of the harder STIs to clear, but it's not impossible.
For more, see Mycoplasma genitalium overview, doxycycline vs azithromycin, chlamydia symptoms in men, and gonorrhea treatment + antibiotic resistance.
