Antibiotic-resistant STIs are sexually transmitted infections that no longer respond to drugs once used to cure them. Gonorrhea is the clearest example — it has outlasted nearly every antibiotic thrown at it. But resistance also shapes how clinicians treat Mycoplasma genitalium and, increasingly, trichomoniasis. Using the right drug at the right dose, and finishing it, keeps these infections curable CDC, drug-resistant gonorrhea.
antibiotics clear them
medicine controls, doesn't cure
| Item | Value |
|---|---|
| Bacterial & parasitic (chlamydia, gonorrhea, syphilis, trich) | curable — antibiotics clear them |
| Viral (herpes, HIV, hepatitis B, HPV) | managed — medicine controls, doesn't cure |
The essentials: what resistance does and doesn't mean
Resistance means a bacterium has changed enough that an antibiotic that used to kill it no longer reliably does. It doesn't mean an infection is untreatable — it means the easy, cheap, older options are off the table and clinicians have to escalate to a narrower set of drugs. That's why guidance changes over time: a regimen that worked a decade ago may be dropped not because it's unsafe, but because too many strains shrug it off.
First, the dividing line that matters most. Whether an STI can be cured at all depends on its cause. Bacterial and parasitic infections — chlamydia, gonorrhea, syphilis, and trichomoniasis — are cured with antibiotics. Viral infections — herpes, HIV, hepatitis B, and HPV — are controlled with medicine but not cured CDC STI Treatment Guidelines, 2021. Resistance is a bacterial and parasitic problem. Antibiotics do nothing for a virus, and taking them "just in case" for herpes or HIV is useless and actively feeds resistance in the bacteria you're carrying.
How antibiotic resistance works across the major STIs
Every time a population of bacteria meets an antibiotic, the few that happen to survive are the ones that pass on their genes. Under-dosing, stopping early, or using a drug the bug has already learned to dodge all speed this up. The story plays out differently for each pathogen.
Gonorrhea ("super gonorrhea")
Gonorrhea is the headline. Over the years it has grown resistant to nearly every antibiotic once used against it — the sulfa drugs, penicillins, tetracyclines, and fluoroquinolones all fell, one by one. That history is why the only currently recommended treatment is a single ceftriaxone injection. There's no oral first-line backup anymore for most people, so this drug is the line clinicians are guarding hardest. Taking the right drug at the right dose isn't a formality here — it's what keeps gonorrhea curable at all. The main side effect of the shot is soreness at the injection site. You can read what to look for on a positive result and how the diagnosis is confirmed on our gonorrhea test page.
Mycoplasma genitalium (MG)
MG is a slow-growing bacterium that causes urethritis in men (burning, discharge) and cervicitis and pelvic inflammatory disease in women (inflammation of the upper reproductive tract that can threaten fertility). It's a resistance problem people rarely hear about. A large share of strains now resist the macrolide antibiotics that were once the go-to, so treatment is escalated in stages — often resistance-guided, meaning the lab checks which drugs the specific strain will respond to before the second drug is chosen. MG is also why a lingering urethritis that didn't clear after standard chlamydia treatment gets a second, harder look.
Trichomoniasis (trich)
Trich is caused by a single-celled parasite, not a bacterium, but reduced susceptibility to its core drugs — metronidazole and tinidazole — does occur and can cause treatment to fail. When that happens, clinicians escalate the dose or switch to the alternative agent rather than abandoning treatment CDC, trichomoniasis treatment. One practical catch with these drugs: they react badly with alcohol. Avoid alcohol during treatment and for a short time after you finish, or you risk nausea, flushing, and vomiting.
Chlamydia and syphilis
Chlamydia is typically treated with doxycycline, which still works well; clinically meaningful resistance hasn't taken hold the way it has in gonorrhea. Doxycycline can cause stomach upset and sun sensitivity, so take it with food and stay out of strong sun. Syphilis remains reliably treatable with penicillin and has not developed the resistance seen elsewhere — a reminder that resistance is pathogen-specific, not a blanket inevitability.
What treatment actually looks like in practice
For most curable STIs, treatment is a short course of pills or a single injection — far less involved than people fear. It's often free or low-cost at a health department or Planned Parenthood, and your partners can frequently be treated without their own appointment through expedited partner therapy, where your clinician sends medication or a prescription home with you for them.
| Infection | Type | Typical approach | Resistance note |
|---|---|---|---|
| Gonorrhea | Bacterial | Single ceftriaxone injection | Resistant to nearly every older drug — last reliable first line |
| Chlamydia | Bacterial | Doxycycline (oral course) | Still responds well; take with food, avoid sun |
| Trichomoniasis | Parasitic | Metronidazole or tinidazole | Some reduced susceptibility; escalate dose/switch drug; no alcohol |
| Mycoplasma genitalium | Bacterial | Staged, often resistance-guided | High macrolide resistance; second drug chosen by testing |
| Syphilis | Bacterial | Penicillin | No meaningful resistance |
A few rules apply no matter which infection you're treating:
- Take the full course exactly as prescribed. Stopping early because you feel better is the single most common mistake — and it's how an infection quietly persists or bounces straight back.
- Make sure partners are treated too. An untreated partner re-infects you the moment you resume sex, no matter how perfectly you took your own medicine.
- Wait to have sex until you and your partners have finished treatment and any wait period your clinician gives — often about a week after a single-dose treatment — so you don't pass it back and forth.
- Feeling better is not proof of cure. Most people improve within a few days, but some infections need a test-of-cure or a retest weeks to months later to confirm it's gone.
- Skip the home remedies. Yogurt, garlic, douching, and detoxes don't cure any bacterial or viral STI. There is no over-the-counter product that works — you need the specific prescription drug and a real diagnosis.
Side effects are usually mild and manageable; we cover the common ones drug by drug in our guide to std antibiotic side effects and what to expect.
What this page does not cover
This is a primer on what resistance means and how regimens are chosen — not a dosing manual. Exact doses, durations, and second-line regimens are decided by your clinician based on the infection, your test results, and any allergies. If you're trying to figure out whether you need testing at all, start with our overview of how to get tested, and if you've had a recent exposure, check when to test after exposure so you don't test too early and get a falsely reassuring result.
When to see a clinician
See a clinician if you have symptoms — discharge, burning with urination, sores, pelvic or testicular pain — or if a partner tells you they tested positive. Go back if your symptoms don't improve within a few days of starting treatment, or return after you finish, since that can signal resistance, reinfection, or a missed second infection. Don't self-treat with leftover antibiotics; the wrong drug at the wrong dose is exactly what drives resistance.