This page is general health information, not medical advice. It cannot tell you whether you have an infection. A clinician can, and the testing options on this site are a good place to start.

Mycoplasma genitalium is a sexually transmitted bacterium that many people have never heard of. Clinicians often shorten the name to M. genitalium or MG. It is less familiar than chlamydia or gonorrhea, and it is handled differently in testing and treatment.

This guide covers what the organism is, what research suggests about it, what the symptoms can look like, and when the CDC recommends a test. It also explains how to ask about testing in Chicago.

It follows the usual deep-dive layout, but there are no compounds or ingredients to review. M. genitalium is a living organism, so the "composition" section describes its biology instead.

Quick answers

M. genitalium is a bacterium that can infect the urethra, cervix and rectum. It is spread through sexual contact.
Many infections cause no symptoms at all, according to the CDC.
The CDC does not recommend routine screening of people without symptoms.
The CDC does recommend testing in specific situations, such as urethritis or cervicitis that keeps coming back or does not go away.
It is not part of most standard STI panels, so you usually have to ask for it.
It is treatable with antibiotics from a clinician, and resistance testing helps guide the choice.

What M. genitalium is: the biology

M. genitalium belongs to a group of very small bacteria called mycoplasmas. Its defining feature is that it has no cell wall. Most common antibiotics work by attacking cell walls, so this matters for treatment.

It also has one of the smallest genomes of any known bacterium that can reproduce on its own. It depends heavily on the cells it lives in. Because of this, it grows slowly and is hard to grow in a lab, which is part of why it went unrecognized for so long.

The practical result is that it cannot be found with the older culture methods used for some other bacteria. Detection relies on nucleic acid amplification tests, often called NAATs. These look for the organism's genetic material in a urine sample or a swab.

M. genitalium symptoms

The CDC's STI Treatment Guidelines (2021) say M. genitalium has been linked to urethritis in people with a penis and to cervicitis in people with a cervix. The guidelines also describe an association with pelvic inflammatory disease, or PID.

Symptoms are not specific to this organism. Many infections cause no symptoms. When symptoms do appear, they can overlap with those of chlamydia and gonorrhea.

Symptoms that can appear with urethritis

Burning or discomfort when urinating
Discharge from the penis
Irritation or itching at the opening of the urethra

Symptoms that can appear with cervicitis or PID

Unusual vaginal discharge
Bleeding between periods or after sex
Pain during sex
Lower abdominal or pelvic pain

None of these symptoms can tell you which infection is behind them. Only a clinician and a test can do that. Symptoms can also come from causes that are not infections.

If you notice any of these symptoms, a clinic visit is a good next step. If you have no symptoms, that is also common with this infection. A clinician can talk through your situation with you.

What the research suggests

Research on M. genitalium is still developing. The points below are observations from published work summarized in the CDC guidelines. They are not settled conclusions.

Persistent urethritis. Research suggests M. genitalium accounts for a meaningful share of urethritis that does not respond to first-line treatment for other causes.
Cervicitis and PID. Studies have found the organism more often in people with cervicitis and PID than in those without. That points to an association, but it does not prove how often it is the cause.
Antibiotic resistance. The CDC notes that resistance to some commonly used antibiotic classes is widespread. Research also suggests resistance can develop during treatment. This is the main reason testing is treated carefully.
Screening. The CDC does not recommend screening people who have no symptoms. One concern is that finding and treating infections that would never cause problems may add to resistance. The evidence on benefit is also limited.

Window periods are another open question. The CDC guidelines do not give a window period for M. genitalium tests that I can cite here. If you are wondering when a test would be reliable after a possible exposure, ask the clinician who is testing you.

When the CDC recommends testing

The CDC STI Treatment Guidelines (2021) point to testing in a few situations:

Persistent or recurrent urethritis in people with a penis
Persistent or recurrent cervicitis in people with a cervix
PID, where testing for M. genitalium should be considered
Sexual partners of someone who has been diagnosed with M. genitalium

The word "persistent" matters here. It generally means symptoms that continue after a course of treatment for the more common causes. A clinician decides whether your situation fits.

Outside these situations, the CDC guidance is to test for the infections that are routinely screened. Those include chlamydia, gonorrhea, syphilis and HIV, depending on your age, anatomy and exposures.

Why it is not on standard panels

If you have had a routine STI panel and it came back negative, that panel most likely did not include M. genitalium. A few reasons explain this.

The CDC does not recommend screening people without symptoms, so labs and clinics do not build it into routine screening.
It needs a separate NAAT, not the same one used for chlamydia and gonorrhea.
Resistance testing, which the CDC prefers when available, adds another layer that not every lab offers.

Because of this, you may need to ask for it by name. A clinician who is evaluating symptoms that will not go away can order it.

Treatment and resistance-guided care

M. genitalium is a bacterial infection, and bacterial STIs can be cured with treatment from a clinician. The details are where it gets more complicated than other bacterial STIs.

Because the organism has no cell wall and resistance is common, the CDC guidelines favor resistance-guided treatment. When a lab can test for markers of resistance, the result helps the clinician choose which antibiotics to prescribe and in what sequence. When that testing is not available, the guidelines describe a different approach.

Only a clinician can decide which prescription is right for you. Do not use leftover antibiotics or take someone else's. Doing so can make a later infection harder to treat.

After treatment, a clinician may recommend that sexual partners be evaluated. The CDC advises avoiding sex until treatment is complete and symptoms have resolved, to prevent passing the infection back and forth. Your clinician will tell you how long that is for your case.

Safety profile and who should talk to a clinician first

There is no product to buy and no home remedy for M. genitalium. The "safety" questions here are about testing and treatment.

Testing is low risk. A urine sample or a swab is typical. Discomfort is usually minimal.
Antibiotics have contraindications. Allergies, pregnancy, other medicines and kidney or liver conditions can all change which antibiotics are suitable. Tell the clinician about all of them.
Pregnancy. If you are pregnant or could be, say so at the start of the visit. It affects which treatments a clinician considers.
Ongoing symptoms. Pelvic pain, fever or pain in the testicles needs prompt medical attention. A clinician can check for complications.

Anyone sexually active can ask for testing, whatever their gender or orientation. Clinicians use the same questions about symptoms, partners and exposures for everyone.

Quality indicators: what a good testing visit looks like

For this topic, "sourcing and quality" means finding care that can actually handle M. genitalium. These are reasonable things to look for.

A clinician is involved. The CDC's approach depends on symptoms, history and treatment response. That is a clinician's judgment, not a checkbox on a form.
The clinic can say whether it runs the test. If staff are unsure, ask whether they can order it through a lab, or refer you.
The clinic can discuss resistance testing. You can ask whether the lab offers it.
Results come with a follow-up plan. A good visit explains what happens if the result is positive, negative or unclear.
Privacy is explained. Ask how results are shared and who sees them.

Getting tested in Chicago

Chicago has several public and nonprofit clinics that provide sexual health care. The clinic pages I reviewed list services such as chlamydia, gonorrhea, syphilis and HIV testing. They do not say whether each site tests for M. genitalium.

That means the best approach is to call first and ask. Tell them you are asking about M. genitalium, and mention any symptoms that have not gone away.

The Chicago Department of Public Health runs Sexual Health Specialty Clinics. Its sexual health services page lists locations in Lakeview, Austin and Roseland, and says care is provided regardless of ability to pay or insurance status. The page asks insured patients to bring their insurance card. It does not say visits are free, and it advises calling ahead to verify hours. Walk-ins are limited, so calling for an appointment is the safer plan. The page is at the Chicago Department of Public Health sexual health services.

Cook County Health runs a walk-in STI Screening Clinic at the Ruth M. Rothstein CORE Center, 2020 W. Harrison St. Its website says same-day HIV and STI services are provided. CDC GetTested lists a sliding scale for this site. You can reach the clinic by phone at 312-572-4700, Monday through Friday, 8:30 am to 3:30 pm.

Howard Brown Health runs a walk-in sexual health clinic with no appointment needed, seeing patients first come, first served. It describes the service as low-cost and offers a Sliding Fee Discount Program based on income and family size. Its Sheridan, 63rd Street and Broadway Youth Center locations are listed on its walk-in page. The main number is 773.388.1600.

You can compare all of these options, with addresses and details, in the local testing list. For a wider look at costs and how to choose, see where to get tested and what it costs.

To find other sites, the CDC runs GetTested, a locator for STI and HIV testing. The Illinois HIV/STD Hotline at 1-800-243-2437 can also answer questions.

Questions you might ask when you call

Do you test for Mycoplasma genitalium, or can you refer me to a place that does?
Is resistance testing available?
What will the visit cost, and is there a sliding scale?
Do I need an appointment, or can I walk in?

Privacy, consent and partners in Illinois

Under the Illinois Consent by Minors to Health Care Services Act (410 ILCS 210/4), a minor aged 12 or older who may have come into contact with a sexually transmitted infection can consent to care related to prevention, diagnosis or treatment. Parental consent is not necessary. The law says providers should make reasonable efforts to involve family if they believe it will not be harmful, and that each STD incident must be reported to public health.

Illinois rules list AIDS, HIV infection, syphilis, gonorrhea, chlamydia and chancroid as reportable infections (77 Ill. Adm. Code 693). M. genitalium is not on that list. Clinicians report cases within seven days of diagnosis or treatment, and in Chicago those reports go to the city health department.

Illinois law also allows expedited partner therapy for chlamydia, gonorrhea and trichomoniasis, according to the CDC's legal status page. It does not cover M. genitalium. For partners, the usual path is for them to see a clinician directly.

What to take away

M. genitalium is real, treatable and often silent. The CDC recommends testing when urethritis or cervicitis persists or returns, and in a few other situations. It does not recommend screening people without symptoms.

Because it is not on standard panels, you usually need to ask for it. Treatment is more careful than for other bacterial STIs because resistance is common. A clinician can guide that choice, ideally with resistance testing.

If you are in Chicago and have symptoms that have not cleared, call a clinic and ask about it by name. Free and low-cost options exist across the city.

Mycoplasma Genitalium: What It Is and Where to Get Tested in Chicago