Mycoplasma Genitalium in Men｜Symptoms, Testing, Treatment & Antimicrobial Resistance Guide

Mycoplasma genitalium is a relatively newly discovered STI pathogen, identified in the 1980s. With wider availability of PCR testing, detection rates have climbed, and clinical attention has grown rapidly in recent years.

The guidelines of the European Association of Urology (EAU) and the U.S. Centers for Disease Control and Prevention (CDC) position Mycoplasma genitalium as a leading cause of non-chlamydial non-gonococcal urethritis (NCNGU), responsible for 15-35% of cases in men. In Japan as well, insurance-covered PCR testing is becoming more accessible, and detection in STI care is steadily increasing.

Another major reason Mycoplasma infection has become a concern is the rapid global rise in resistance to macrolide antibiotics (azithromycin). Strategies for tackling resistant strains are discussed in detail in section H2-7.

Overseas epidemiological studies report that Mycoplasma genitalium carriage in the general adult male population is around 1-3%. Among men visiting STI clinics, some reports show that 10-20% test positive for Mycoplasma.

Both sexes can become infected, but men tend to develop more visible symptoms (urethritis), while women frequently remain asymptomatic carriers. As a result, the typical pattern is that men notice symptoms, seek care, and the infection is found on testing.

The most common presentation of Mycoplasma infection in men is urethritis. Characteristic complaints include:

• Mild pain or stinging on urination: Not as intense as with gonorrhea, but discomfort with every void.
• Itching or tingling in the urethra: Sensation persists even when not urinating.
• Small amounts of clear-to-cloudy discharge: Often only a tiny stain on underwear in the morning.
• Increased urinary frequency: Sometimes accompanied by residual urine sensation or frequency.
• Genital discomfort: Tends to worsen after sexual activity.

These symptoms are very similar to chlamydial urethritis. In fact, it is not uncommon for someone to be tested thinking it is chlamydia infection, get a negative result, and then have Mycoplasma identified on follow-up testing.

The most common STIs causing male urethritis are gonorrhea, chlamydia, Mycoplasma, and Ureaplasma. Symptom patterns differ as follows:

Because Mycoplasma causes mild, slow-developing symptoms, infected individuals often do not notice it and may transmit it unknowingly to partners.

Reports indicate that 30-50% of male Mycoplasma cases remain asymptomatic, making it a “silent STD” that spreads to partners without the carriers awareness.

Left untreated, the following complications may occur:

• Chronic urethritis: Persistent mild symptoms that significantly reduce quality of life.
• Prostatitis: Causes perineal discomfort, urinary difficulty, and pain on ejaculation.
• Epididymitis: Scrotal swelling, pain, and fever. Can contribute to male infertility.
• Reactive arthritis: Rare, but can include arthritis and conjunctivitis (Reiter syndrome-like presentation).

Letting mild discomfort slide can lead to these complications or to male infertility. Early testing is essential if you notice any unusual symptoms.

• Vaginal intercourse: The most common route. Risk increases with condomless sex.
• Oral sex: Can cause pharyngeal infection. An important transmission route from male to female partners.
• Anal sex: Risk of rectal infection. Recognized as a transmission route among men who have sex with men.
• Deep kissing: Pharynx-to-pharynx transmission is theoretically possible but considered uncommon.

Because Mycoplasma is spread by mucosa-to-mucosa contact, any mucosal site (genital, oral, or rectal) can become infected. Pharyngeal Mycoplasma infection is usually asymptomatic, making it easy to overlook.

The incubation period of Mycoplasma genitalium typically spans 1 to 5 weeks after exposure. This is longer than chlamydia (1-3 weeks) and considerably longer than gonorrhea (2-7 days).

• Day 1 to week 1 after exposure: Mostly asymptomatic; testing may not detect the infection reliably.
• 1 to 3 weeks after exposure: Many people begin to feel mild urethral discomfort or itching.
• 3 to 5 weeks after exposure: Typical symptoms appear, such as pain on urination and small amounts of discharge.
• Asymptomatic course: 30-50% of those infected remain carriers without clear symptoms.

Because the incubation is long and symptoms are mild, most patients cannot identify which sexual encounter caused the infection. If you notice any discomfort within 1-2 months of a risky encounter, testing is recommended.

PID = Pelvic Inflammatory Disease. Severe cases in women can raise the risk of infertility and ectopic pregnancy.

It is not unusual for people with Mycoplasma to also have concurrent chlamydia or gonorrhea. STI clinic data show that 10-20% of those positive for Mycoplasma also carry chlamydia or gonorrhea at the same time.

It is therefore a mistake to assume “I tested negative for chlamydia and gonorrhea, so I am safe.” If symptoms persist, a comprehensive STI panel that includes Mycoplasma is advisable.

At Mens Care Clinic, we offer set test menus tailored to your symptoms and risk exposure. Comprehensive panels that also cover HIV, syphilis, and hepatitis B are available.

For Mycoplasma testing in men, specimens are collected based on the suspected site of infection:

• First-void urine PCR: The standard test for urethral infection. Collect the first 20-30 ml of urine. Painless.
• Pharyngeal swab PCR: Recommended when there is oral-sex exposure. A cotton swab gently brushes the back of the throat.
• Rectal swab PCR: Added when there is anal-sex exposure.
• Gram stain of urethral discharge: A supplementary microscopic test to confirm inflammation.

For men, testing can be completed with a urine sample alone, posing virtually no physical burden. Pharyngeal and rectal tests are chosen based on exposure history.

The ideal time to test for Mycoplasma infection is 2-3 weeks after exposure. Testing earlier may produce a false negative because the bacterial load is still low.

• Day 3-7 after exposure: Low likelihood of positivity. Retesting needed.
• 2-3 weeks after exposure: Recommended timing; sensitivity is near maximum.
• While symptoms are present: Bacterial load is sufficient and detection is almost certain.
• Post-treatment confirmation: A “Test of Cure” should be performed 4 weeks after completing treatment.

If symptoms are already present, do not wait. Seek care promptly. The sooner testing and treatment begin, the lower the risk of passing the infection to partners.

The cost of Mycoplasma testing varies by clinic and test set. Typical ranges are below:

Note: PCR testing for Mycoplasma genitalium may be covered by national health insurance under specific conditions, but when performed as STI screening it is typically out-of-pocket.
Note: Treatment cost (prescription drugs) for positive cases is charged separately.

Mail-order test kits (collect urine at home, mail in, then receive results) are widely available, but note the following:

• A positive result still requires a clinic visit: Antibiotic prescriptions require a physicians examination.
• Variability in collection technique: Home collection may reduce accuracy and yield false negatives.
• Resistance cannot be assessed: Follow-up when treatment fails becomes difficult.
• Slower turnaround: Treatment is often delayed.

If you want a reliable diagnosis and treatment, it is more reassuring to be tested at a medical institution from the start. Mens Care Clinic also offers online consultations, so a workflow of kit shipment, video consultation, and prescription is available without an in-person visit.

Azithromycin (brand name Zithromax, etc.) has long been the international first-line agent for Mycoplasma genitalium. The two representative regimens are:

• Single-dose (1 g once): Excellent adherence, but promotes selection of resistant strains. Its recommendation has weakened in recent years.
• Extended course (500 mg on day 1, then 250 mg for 4 days; total 5 days): Increasingly preferred for reducing the risk of resistance emergence.

However, because of macrolide resistance (discussed below), azithromycin failures are increasing, and pre-treatment resistance genotyping is becoming more common.

Doxycycline (brand name Vibramycin, etc.) retains some activity against macrolide-resistant strains. It is also a standard option for chlamydia, which makes it useful in cases of co-infection.

• Regimen: 100 mg twice daily for 7 days (standard).
• Efficacy: When used alone for Mycoplasma, cure rates are relatively modest at about 30-40%.
• Combination therapy: Sequential therapy of 7 days of doxycycline followed by 7 days of moxifloxacin has been reported to improve cure rates.
• Side effects: Gastrointestinal symptoms and photosensitivity (sunscreen is recommended).

Moxifloxacin (brand name Avelox, etc.) achieves the highest cure rate against Mycoplasma genitalium and serves as the salvage agent for macrolide-resistant strains.

• Regimen: 400 mg once daily for 7-10 days.
• Efficacy: Cure rates exceed 90%, the highest among standard options.
• Positioning: Salvage therapy when first- or second-line treatment fails.
• Side effects: Tendon rupture, QT prolongation, hypoglycemia, and other more serious adverse effects; should be used with care.

Overusing moxifloxacin also risks fostering resistance, so modern infectious-disease practice reserves it strictly for cases that truly require it.

Following these guidelines during treatment is key to successful eradication and to preventing transmission to partners:

• Take the full prescribed course: Do not stop early on your own even if symptoms improve. That raises the risk of resistance.
• No sex during treatment: Avoid sexual activity for 1-2 weeks after completing treatment as well.
• Treat partners at the same time: Even if you are cured, you can be reinfected by an untreated partner (ping-pong infection).
• Always have a Test of Cure: Re-test 4 weeks after finishing treatment to confirm a negative PCR.
• Alcohol: Avoid heavy drinking while on antibiotics.

Reported macrolide resistance rates of Mycoplasma genitalium in Western countries and parts of Asia have been climbing year by year. Representative figures include:

Note: Rates vary by study and time period; all regions show an upward trend in the most recent data.

The main drivers behind rising macrolide resistance are thought to be:

• Overuse of single-dose azithromycin (1 g): Sub-optimal antimicrobial pressure selects resistant strains.
• Spillover from chlamydia treatment: Azithromycin given for chlamydia acts on co-existing Mycoplasma and promotes resistance.
• Personal importation and self-treatment: Inadequate dosing and duration accelerate resistance.
• Ping-pong infection from untreated partners: Repeated cycles of reinfection and re-treatment entrench resistance.

Practices such as “I just took a single antibiotic tablet” or “I bought it cheaply through overseas mail order” are among the biggest contributors to resistance. Always take the full course exactly as your physician directs.

If symptoms fail to improve after azithromycin treatment, or if the Test of Cure is still positive, a macrolide-resistant strain is likely. The standard workflow is:

• STEP 1: Resistance genotyping (where available): Test for mutations in the 23S rRNA gene.
• STEP 2: Switch medication: Sequential therapy of doxycycline (7 days) followed by moxifloxacin (7 days).
• STEP 3: Re-test the partner: Rule out reinfection.
• STEP 4: Test of Cure: Confirm PCR negativity 4 weeks after completing treatment.

European and U.S. guidelines have increasingly adopted resistance-guided therapy, selecting drugs based on resistance genotyping from the outset. This approach is gradually being introduced in Japan.

Female partners infected with Mycoplasma may experience the following symptoms and complications:

• Cervicitis: Increased vaginal discharge, painful intercourse, and breakthrough bleeding.
• Pelvic Inflammatory Disease (PID): Lower abdominal pain and fever. Severe cases may require hospitalization.
• Increased infertility risk: Through tubal inflammation, leading to tubal obstruction or adhesions.
• Increased ectopic pregnancy risk: A secondary effect of fallopian tube damage.
• Pre-term birth or miscarriage during pregnancy: Reported (debate continues).
• Asymptomatic infection: Over 50% remain asymptomatic and unaware.

Because women tend to develop more serious complications, if a man tests positive he must encourage his partner to see an OB-GYN. Early testing and treatment can prevent progression to severe disease.

Telling a partner that you have an STI is emotionally difficult, but hiding it is far riskier. The following approaches may help:

• State the facts concisely: Say plainly, “The test found Mycoplasma. I want us to be treated together.”
• Avoid blame on either side: Focus on the present and future rather than pursuing where the infection came from.
• Share medical information: Explain that “many carriers are asymptomatic” and “without joint treatment, reinfection is likely.”
• Suggest a clinic: List OB-GYNs or STI clinics where she can be seen.
• Offer to cover costs: Volunteering to pay for testing and treatment lowers the barrier.

Mens Care Clinic can also issue a partner referral letter when needed. Please feel free to ask.

Key follow-up steps to prevent recurrence and reinfection of Mycoplasma infection:

• Test of Cure 4 weeks after treatment: Mandatory: confirm PCR is negative.
• Confirm partner has also completed treatment: Finish treatment at the same time.
• Abstain from sex during treatment and until cure is confirmed: Wait 1-2 weeks after completing therapy.
• Re-test in 3-6 months if reinfection risk exists: For example, if there was activity with a new partner.

Do not assume “the symptoms are gone, so I am cured.” Always confirm cure at a medical institution. Mycoplasma can persist after symptoms disappear, and visible improvement does not always equal microbiological eradication.

Condoms are the foundation of STI prevention, but they have specific advantages and limits with respect to Mycoplasma:

• Significantly lowers vaginal-sex transmission risk: When used correctly, reduces the risk of chlamydia, gonorrhea, and Mycoplasma transmission by 80-90%.
• Recommended for oral sex as well: To help prevent pharyngeal infection.
• Put on for the entire act: Late application reduces effectiveness.
• Limitations: Mucosal contact at sites the condom does not cover (scrotum, perineum, lips) can still permit transmission.

Condoms are not “100% prevention,” but they are the most practical single measure for reducing overall STI risk. Treat them as essential with new partners or when you have multiple partners.

Because Mycoplasma infection is often asymptomatic, waiting for symptoms tends to mean detection comes too late. Sexually active adult men are recommended to undergo STI screening 1-2 times per year. Useful checkpoints include:

• Beginning of a new relationship: Ideally both partners are tested for mutual peace of mind.
• When a partner tests positive for an STI: Get tested immediately, even if asymptomatic.
• During periods of multiple partners: Testing every 3-6 months is advised.
• Marriage or planning a pregnancy: Testing both partners is strongly recommended.
• After condomless sex: Test 2-4 weeks afterward.

Regular testing is the best strategy that combines early detection, early treatment, and prevention of onward transmission.

Practical day-to-day measures to lower infection risk include:

• Open conversations with your partner about STIs: Build a culture of sharing testing history.
• Refrain from sex when feeling unwell or noticing discomfort: Hold off until testing, even for minor symptoms.
• Limit partners: Concentrating on a steady partner reduces risk.
• Test after sex-industry exposure: Schedule a test 2-3 weeks after the exposure.

Not only for Mycoplasma, the “condoms + regular testing + early treatment” trio is the foundation of STI prevention. Faithful execution of the basics is the strongest prevention.

The flow of STI care at Mens Care Clinic is as follows:

• STEP 1 Booking: Book via web, phone, or LINE (same-day available). Anonymous consultations welcome.
• STEP 2 Interview & Exam: The physician confirms symptoms and exposure history (5-10 min).
• STEP 3 Specimen collection: Completed with urine alone. Pharyngeal or rectal tests on request.
• STEP 4 Result notification: Results delivered by email or phone in 3-7 days.
• STEP 5 Start of treatment (if positive): Antibiotics dispensed in-clinic or shipped.
• STEP 6 Test of Cure: Re-test 4 weeks after completing treatment.

First-visit and follow-up fees are free. You pay only for the actual testing and prescription costs.

For those who feel “embarrassed to visit a clinic” or “too busy to commute,” online STI care is a strong option. Consult a physician by smartphone or PC, then have the test kit and prescription shipped to your home.

• Online consultations are available from the first visit.
• Test kits arrive in discreet packaging that hides the contents.
• Results are notified by email or LINE; treatment can begin online if positive.
• Evening and weekend slots are available, so you can be seen after work.

Mens Care Clinic places the utmost importance on privacy protection in STI care:

• Fully private rooms for consultations: Patient flow designed so you do not cross paths with others from the waiting area to the exam room.
• Male-physician care available on request: We accommodate preferences for a same-sex physician.
• No insurance card needed: Out-of-pocket care means no risk of disclosure via insurance to family or workplace.
• Discreet packaging for prescriptions: Contents are not visible from outer packaging in home delivery.
• Strict medical records management: No disclosure to any third party.

STIs are sensitive matters, so we have made it as easy as possible for patients to seek care comfortably.

No, they are different bacteria. Sexually-transmitted Mycoplasma is Mycoplasma genitalium / hominis, spread by sexual contact. The cause of Mycoplasma pneumonia, common in children and young people, is Mycoplasma pneumoniae, spread by droplet infection in the respiratory tract. They belong to the same family but differ entirely in transmission route and clinical course. Treat them as distinct entities.

Spontaneous resolution should not be expected. Symptoms may temporarily ease, but as long as the bacterium remains it can flare, cause chronic urethritis or prostatitis, and spread to partners. Reliable cure requires oral antibiotics. Do not judge yourself cured just because symptoms have gone; always confirm negativity with a Test of Cure.

A macrolide-resistant strain is likely, so the next step is typically sequential therapy of doxycycline (7 days) followed by moxifloxacin (7 days). Do not add or change antibiotics on your own. See a physician, identify the cause of treatment failure (resistance, reinfection, non-adherence, etc.), and decide the next regimen together. Resistance genotyping is helpful where available.

Yes, partner co-treatment is essential even without symptoms. Over 50% of women carrying Mycoplasma are asymptomatic. If you alone are treated, an untreated partner can cause “ping-pong reinfection” that resets your treatment. Encourage your partner to see an OB-GYN or STI clinic.

Yes, Mycoplasma can be transmitted through oral sex. Infection in the throat is called “pharyngeal Mycoplasma.” Most cases are asymptomatic or cause only mild throat discomfort. Pharyngeal infection is hard to notice and may be passed to new partners through oral sex. If you have had a risky encounter, a pharyngeal swab PCR is recommended.

In men, untreated infection can cause epididymitis and prostatitis, which may indirectly affect sperm motility and morphology and increase infertility risk. In women, the risks are more serious: untreated Mycoplasma can lead to PID, then tubal obstruction, then infertility and ectopic pregnancy. Couples trying to conceive or planning to have children in the future should prioritize early detection and treatment. See also the male infertility page.

It is recommended to abstain from sex for at least 1-2 weeks after completing antibiotics. Ideally, wait until a Test of Cure 4 weeks after treatment is negative, and until your partner has also finished treatment. Resuming too early can cause reinfection or treatment failure.

Strongly discouraged. There are three reasons. First, risk of counterfeit drugs (Japans Ministry of Health, Labour and Welfare has reported that roughly 40% of medicines bought via overseas mail order are counterfeit). Second, selection of resistant strains (improper dose and duration accelerate macrolide resistance). Third, no Test of Cure (undetected residual bacteria lead to chronic infection and partner transmission). Always get a prescription from a clinic.

PCR testing for Mycoplasma genitalium may be covered by Japanese national health insurance under specific conditions, but when used as STI screening for asymptomatic individuals it is generally out-of-pocket. Antibiotic treatment is often covered. Please confirm details with the clinic at the time of consultation. Note that Mens Care Clinic operates under self-pay care, so no insurance card is required.

Ureaplasma (Ureaplasma urealyticum / parvum) is a close relative of Mycoplasma and can also cause non-chlamydial urethritis in men. It is transmitted by sexual contact, diagnosed by PCR, and treated with antibiotics, all shared in common with Mycoplasma. Its pathogenicity, however, is less well established than that of Mycoplasma genitalium and it is sometimes regarded as commensal flora. Tests are commonly bundled as a combined Mycoplasma + Ureaplasma panel.

Yes, very much. Mycoplasma is asymptomatic in 30-50% of men, and without awareness people may infect partners and lead to complications like PID and infertility. Around the start or end of a new relationship, at marriage or pregnancy planning, or during periods of multiple partners, undergoing STI screening 1-2 times per year is recommended even without symptoms.

Because Mens Care Clinic operates as self-pay care, no insurance card is required, so there is no risk that family or workplace will learn about your consultation through insurance claims. Records are managed strictly and never disclosed to any third party. Prescriptions shipped to your home come in packaging that does not reveal the contents. We make every effort to protect privacy. Please feel free to consult us.