Mycoplasma genitalium is usually curable, but the word comes with a condition: cure now depends on matching the antibiotic to the strain. Because more than half of strains in many areas resist the old single-dose azithromycin, clinicians use a two-step, resistance-guided course. Done right, most infections clear — done blindly, treatment often fails.
rising — guides therapy
doxy → moxifloxacin
| Item | Value |
|---|---|
| US adults infected | ~1–2% |
| Azithromycin resistance | ~50% — rising — guides therapy |
| Often | no symptoms |
| Treatment | resistance-guided — doxy → moxifloxacin |
Is Mycoplasma genitalium curable?
Yes — in most cases M. genitalium (often shortened to Mgen or MG) can be fully cleared with the right antibiotics. The catch is that "the right antibiotics" is no longer a single prescription you can hand out reflexively. This bug lacks a cell wall, so penicillins and cephalosporins (the beta-lactam family) do nothing to it CDC, 2021. That leaves a short list of drugs, and the workhorse of that list — azithromycin — is losing ground fast to resistance. So "curable" is true, but it's conditional on testing and sequencing the treatment correctly. If you want the full step-by-step regimen, see our deep dive on mgen treatment.
What "cure" actually means here
Cure means microbiological eradication — the organism is gone from your urine or genital tract, confirmed by a test that comes back negative, not just symptoms that quieted down. That distinction matters more for Mgen than for most STIs, because it's a slow, low-grade infection that can keep simmering without obvious signs. A clinician's goal isn't "you feel fine"; it's "the test no longer detects it." Those two things don't always line up, which is why follow-up testing is built into modern management.
The treatment that clears it
Current CDC guidance uses resistance-guided, two-step therapy, and it always opens the same way: doxycycline first to knock the bacterial load down, then a second drug chosen by whether the strain carries a macrolide-resistance mutation. This isn't optional fine-tuning — it's the reason cure rates hold up at all.
- If the strain is macrolide-sensitive: doxycycline 100 mg twice daily for 7 days, followed by azithromycin 1 g once, then 500 mg daily for 3 days.
- If the strain is macrolide-resistant (or resistance testing isn't available): doxycycline 100 mg twice daily for 7 days, then moxifloxacin 400 mg daily for 7 days NYSDOH/Johns Hopkins.
Notice what's missing: the old standby of a single 1 g azithromycin dose on its own. That worked when most strains were susceptible, but it now fails frequently and — worse — a half-treated infection can be pushed toward resistance. That's why a specific M. genitalium test, not a standard STI panel, is the linchpin: the panel won't tell you whether your strain is macrolide-resistant, and that single piece of information decides which second drug you get. This is exactly the point made in our explainer on why awareness is key in mg diagnosis and treatment.
On the practical side, treatment is a defined course of pills — finish every dose even after you feel better, because stopping early is one of the most common ways an infection isn't fully cleared. Take doxycycline with food and water and stay upright for a bit afterward to avoid stomach upset. And ask your clinician whether your partner should be treated, since a symptomatic partner who tests positive can pass it right back to you.
Sensitive vs. resistant: how the two paths compare
| Factor | Macrolide-sensitive strain | Macrolide-resistant strain |
|---|---|---|
| First step | Doxycycline 100 mg twice daily, 7 days | Doxycycline 100 mg twice daily, 7 days |
| Second step | Azithromycin 1 g once, then 500 mg daily for 3 days | Moxifloxacin 400 mg daily, 7 days |
| What decides it | Resistance test shows no macrolide mutation | Resistance test shows a mutation, or testing unavailable |
| Why it matters | Azithromycin still reliable here | Azithromycin would likely fail; moxifloxacin needed |
Why symptoms fading isn't the same as cured
This is the trap. Doxycycline lowers the bacterial load early in treatment, so urethral burning or discharge often eases within days — but that first drug alone usually doesn't eradicate Mgen. The second-step antibiotic is what finishes the job. People who feel better, skip the rest of the course, or never confirm a cure can stay quietly infected and infectious. Add in the resistance problem, and "I felt fine after a few pills" is a poor proxy for "it's gone." The honest framing: feeling better is encouraging, a negative test is proof.
Follow-up and retesting
Because cure isn't guaranteed — especially with resistant strains — a test-of-cure is part of standard management. Your clinician will tell you when to come back; don't retest too early, since dead bacterial fragments can linger and give a false positive. If the follow-up test is still positive, that's not failure on your part — it usually means the strain was resistant to the drug you got, and treatment moves to the next agent. Reinfection from an untreated partner is the other common reason a repeat test stays positive, which loops back to treating partners. For timing of any STI test relative to a sexual contact, see our guide on when to test after exposure.
What happens if Mgen goes untreated
Untreated, M. genitalium isn't harmless. In men it's an established cause of persistent or recurrent urethritis (inflammation of the urethra that produces lingering discharge or burning that won't resolve). In women the stakes are higher: it's linked to cervicitis (inflammation of the cervix), pelvic inflammatory disease or PID (infection spreading into the uterus and fallopian tubes, which can scar them), preterm delivery in pregnancy, and infertility — with roughly a twofold increased risk of tubal-factor infertility reported. The slow, often symptom-free course is exactly what makes it dangerous: damage can accumulate while you feel nothing.
The resistance picture is why public-health bodies are paying attention at all. Macrolide-resistance mutations now exceed 50% in many areas — over 62% in one US STI clinic — so the older single-dose approach fails often enough to be unreliable. We unpack that trend in why health agencies around the world are worried about mycoplasma genitalium.
When to see a clinician
Get checked if you have urethral or vaginal discharge, burning with urination, pelvic pain, bleeding after sex, or symptoms that didn't clear after a previous STI treatment — that last one is a classic Mgen clue. Diagnosis is straightforward: most cases come from a simple sample — a urine cup, a self-collected swab, or a quick exam — with results usually back in a few days, and it's free or low-cost at health departments, Planned Parenthood, and Title X clinics. The key is asking specifically for a M. genitalium test, since it's not on every standard panel. You can get tested through a lab that offers Mgen-specific testing, and you can compare testing providers if you want to see who screens for it. A diagnosis here is common, it's treatable, clinics handle it daily, and it says nothing about you as a person.