Partners of someone diagnosed with Mycoplasma genitalium should generally be tested rather than treated blindly. Current CDC guidance supports testing and treating the partners of symptomatic patients who test positive, which reduces reinfection while limiting needless antibiotic use CDC, 2021. Blanket treatment fuels resistance, so a specific Mgen test is the smarter first step.
with the right treatment
testing, not symptoms, decides
| Item | Value |
|---|---|
| Curable? | yes — with the right treatment |
| Tested by | NAAT / lab |
| Often | no symptoms |
| If you may have it | get tested — testing, not symptoms, decides |
Why "test, don't treat blindly" is the rule for Mgen partners
Mgen is unusual among sexually transmitted bacteria. It's mycoplasma genitalium, a bacterium that lacks a cell wall, so penicillins and cephalosporins (the beta-lactams) simply can't touch it. Resistance is the bigger problem: macrolide-resistance mutations now exceed 50% in many areas, with over 62% reported in one US STI clinic, so the old single dose of azithromycin frequently fails.
So partners shouldn't be handed antibiotics on autopilot. Every unnecessary or mismatched course of azithromycin gives the bacterium another chance to select for resistant strains. Testing first tells you whether a partner actually carries Mgen — many won't — and spares the ones who don't from a drug they don't need. For partners who do test positive, treatment can be matched to the infection instead of guessed at.
An Mgen diagnosis is common and treatable. Clinics handle it routinely, and it says nothing about you as a person. Partner management aims to stop the two of you from passing it back and forth, not to assign blame.
How to prevent Mgen — and what each method actually does
Mgen is sexually transmitted, so prevention follows the same logic as other STIs: reduce fluid and mucosal contact, and catch silent infections through screening. No single method is perfect, but combined they cut risk substantially.
- Consistent condom use: condoms used every time lower the risk of the sexually transmitted infections, Mgen included. They're the most accessible barrier and the backbone of prevention.
- Routine testing: Mgen is frequently silent, and screening catches infections that have no symptoms. Testing partners after exposure breaks the reinfection loop that keeps a couple cycling through treatment.
- Treating to clearance: finishing the full course and confirming the infection has cleared before resuming unprotected sex prevents handing it straight back to a partner.
Condoms and their limits
Condoms are effective and worth using every time, but they have real limits with Mgen. They cover the penis, so they reduce contact with infected secretions and mucosa without eliminating it. Skin and mucosal areas a condom doesn't cover can still make contact, and a condom used inconsistently or only partway through an encounter offers far less protection than one used from start to finish.
Condoms lower risk meaningfully, but they're a layer rather than a guarantee. Pairing them with testing closes the gap that barriers alone leave open.
Testing as prevention
For Mgen, testing is prevention. The diagnostic is an FDA-cleared NAAT (nucleic acid amplification test) run on urine or on a urethral, penile-meatal, endocervical, or vaginal swab. It's the same kind of sensitive molecular test used for chlamydia and gonorrhea, just targeting Mgen specifically, so a standard panel may not include it unless you ask. Learn what's involved in mgen testing before you go.
Guidelines don't recommend screening everyone. Testing is aimed at men with recurrent NGU (non-gonococcal urethritis — urethral inflammation that keeps coming back after treatment) and women with recurrent cervicitis (persistent inflammation of the cervix), plus the partners of people who test positive. If you're a partner being evaluated, this is the situation the guidance was written for.
Timing matters. A NAAT needs enough bacterial genetic material present to detect, so testing too soon after exposure can miss an early infection. See when to test after exposure for how long to wait, and you can get tested through a clinic or online order when the timing is right.
Macrolide-resistance testing — the lab step that would tell your clinician whether azithromycin will work — should guide therapy but isn't commercially available in the US. Until it is, clinicians often use a sequential approach instead, which shapes how partners get treated.
What treatment looks like for a partner who tests positive
If a partner tests positive, current guidance calls for resistance-guided treatment: doxycycline first to lower the bacterial load, then azithromycin if the strain is macrolide-susceptible, or moxifloxacin if it's resistant NYSDOH/Johns Hopkins. Because the resistance test isn't widely available, many clinicians run the doxycycline-then-moxifloxacin sequence or follow up to confirm cure. A specific Mgen test, not a generic STI panel, confirms the infection is there before anyone commits to this multi-step regimen.
This is also why "just take my partner's leftover pills" is a bad idea. A single azithromycin dose, the old standard, frequently fails now and can push a susceptible infection toward resistance. Get your own test and your own prescription.
Vaccines, PrEP, and DoxyPEP — do they apply here?
There's no vaccine for Mgen, and HIV PrEP doesn't prevent it. DoxyPEP (doxycycline taken after sex to prevent bacterial STIs) is studied mainly for syphilis, chlamydia, and gonorrhea; it isn't an established Mgen prevention tool, and using doxycycline broadly raises the same resistance concerns that already plague this organism. For now, condoms plus targeted testing remain the realistic prevention toolkit.
Putting it together
Here's how the pieces fit for a couple managing an Mgen diagnosis:
- Index patient: the person diagnosed completes resistance-guided treatment and avoids unprotected sex until cleared.
- Partner: gets tested with a specific Mgen NAAT rather than treated on assumption.
- If the partner is positive: they receive the same sequential, resistance-aware treatment.
- If the partner is negative: no antibiotics — using condoms every time and a follow-up test if symptoms appear is enough.
- Both: hold off on unprotected sex until treatment is finished and, where recommended, cure is confirmed.
| Partner scenario | What guidance supports | Why |
|---|---|---|
| Symptomatic partner, tests positive | Treat with resistance-guided therapy | Active infection; treatment limits reinfection and complications |
| Partner tests negative | No antibiotics; condoms + retest if symptoms | Treating an uninfected person only drives resistance |
| Partner declines testing | Discuss testing first; avoid blind azithromycin | A single old-dose regimen frequently fails and selects resistance |
When to see a clinician
See a clinician if you've been told a partner has Mgen, if you have urethral discharge or burning that doesn't clear after treatment for another infection, or if a partner has recurrent cervicitis. Bring up Mgen specifically, since it isn't always on the default test menu. A clinician can order the right NAAT, interpret timing, and set up the sequential treatment if needed.
Mgen partner treatment FAQ
Should my partner just take antibiotics if I have Mgen?
No — test your partner first. Treating blindly exposes someone who may not be infected to antibiotics and contributes to the macrolide resistance that already makes Mgen hard to cure. Positive partners then get matched, resistance-guided treatment.
Which partners should be tested?
Guidance focuses on the partners of people who test positive, especially when the index patient had symptoms. Beyond that, testing is aimed at men with recurrent NGU and women with recurrent cervicitis rather than everyone.
Will a standard STI panel catch Mgen?
Not always. Mgen needs a specific FDA-cleared NAAT, and it's often left off default panels. If you're being evaluated as a partner, ask for the Mgen test by name.
Why can't the lab tell us which antibiotic will work?
Macrolide-resistance testing should guide therapy but isn't commercially available in the US yet. So clinicians use a sequential approach — doxycycline first, then azithromycin or moxifloxacin — and sometimes confirm cure afterward.
How long should we avoid sex during treatment?
Wait until treatment is complete and, where recommended, a follow-up test confirms the infection has cleared. Resuming unprotected sex too early is the most common way couples reinfect each other. Your clinician will give a specific timeline based on your regimen.
Do condoms fully prevent Mgen?
No, but they help a lot when used every time. They reduce contact with infected secretions but don't cover every area, so pair them with testing for the strongest protection.
Is having Mgen a big deal?
It's common and treatable, and clinics handle it daily. The main challenge is resistance, which is why testing before treating matters. A diagnosis says nothing about you as a person.
Where can I learn more about Mgen?
Our mgen faq answers more questions about symptoms, testing, and follow-up if you want detail beyond partner management.