Mycoplasma Genitalium: The New STD

Yes, you read that right: There’s a new STD in town. You might have already heard of it. It’s called mycoplasma genitalium, and it goes by the nicknames Mg, Mgen, Mycoplasma G, and M. genitalium.

And, it’s actually not so new. Scientists have known about this little guy since the 80s; in 2015, the CDC identified it as an emerging issue; and in December 2017, internet searches for the term “Mycoplasma Genitalium” skyrocketed.

So if it’s been around for so long, then why is the public still so widely unaware of it? That’s a great question that we, unfortunately, don’t have the answer to. All we can do is be a beacon of light in this dark storm of confusion, by providing you with everything that you need to know about mycoplasma genitalium, including what it is, how you can get it, and what all of this means for you.

What is Mycoplasma Genitalium?

Mycoplasma genitalium is a sexually transmitted disease caused by a bacteria aptly named Mycoplasma genitalium. Mgen is just one strain of a group of bacteria called Mycoplasma. There are over 100 strains of different mycoplasmas. They are characterized as the smallest bacteria known of and can’t even be seen under a microscope.

Of these 100 strains of mycoplasmas, four of them are known to be transmitted sexually:

  • Mycoplasma genitalium
  • Mycoplasma hominis
  • Ureaplasma urealyticum
  • Ureaplasma parvum

Mycoplasma genitalium is the most widespread of the four. Studies estimate that between 2 and 4 percent of the population have the infection. This makes it more prevalent than gonorrhea, which is estimated at .5 percent of the population.
Let’s repeat that: Mycoplasma genitalium is estimated to affect more people in America than gonorrhea.

blueberries with one green blueberry signifying the mycoplasma genitalium among the other STDs

Mycoplasma genitalium is estimated to affect more people in America than gonorrhea.

What are the Symptoms?

Mg is usually asymptomatic, meaning that it doesn’t display any symptoms (much like most other STDs). If you do experience symptoms, they can include the following:

  • Vaginal itching
  • Penile itching
  • Unusual vaginal discharge
  • Penile discharge
  • Painful urination
  • Painful sex
  • Bleeding between periods
  • Swelling of the joints (arthritis)

Symptoms for Mg are scarily close to symptoms for chlamydia and gonorrhea. This is troubling because so many people don’t know about Mg. And, even if they know about it, they may not realize that they have to ask to be tested for it.

What Happens if Mgen is Left Untreated?

Untreated Mg can lead to some pretty scary consequences.

Complications in Women

  • Pelvic inflammatory disease (PID)
  • Bacterial vaginosis (BV)
  • Arthritis
  • Infertility
  • Cervicitis
  • Ectopic pregnancy

Complications in Men

  • Urethritis
  • Epididymitis
  • Arthritis
little sprouts growing out of a plot meant to symbolizing mycoplasma g growing

Keep in mind that because so few people get tested for MG, its true complication rate is unknown

How Can You Get Mg?

Mycoplasma G tends to invade the cells lining the urogenital tract (urinary, genital, and reproductive), but it has also been found in rectum and lung cells. Therefore, it’s safe to assume you can get Mg through sexual contact, but scientists are still unsure about the mechanisms through which transmission could occur, which is scary as heck.

Is it spread through skin-to-skin contact, like herpes? Is it airborne, like its cousin mycoplasma pneumoniae? Can it survive on surfaces, like trichomoniasis? We don’t know, because scientists don’t know.

It’s also unclear how long it takes for a person to become infected with mycoplasma genitalium after they’ve been exposed to the bacteria. Mycoplasma genitalium is a slow-growing bacteria, which has, in the past, made testing difficult, as it can take weeks or even months to grow a culture in the lab. So, scientists aren’t sure about the average length of time it takes for the bacteria to cause an infection.

How Do You Test for Mg?

Mycoplasma can be diagnosed with a urine sample or a swab specimen.

There are a few options for testing for Mgen:

1. Ask your doctor (though they might refuse, which is what frustratingly happened to yours truly)
2. Order an at-home test kit (though these are super annoying, as our team found out)
3. Order a lab test online

At this time, does not sell mycoplasma genitalium tests. However, our sister site does.

link to purchase mycoplasma genitalium test

Is Mgen Treatable?

Yes! Just like chlamydia, gonorrhea, and all the other bacterial infections, mycoplasma can be cured with antibiotics. However, the mycoplasma family of bacteria is a little special because they don’t have cell walls. This matters because most antibiotics used to eliminate bacteria do so by dissolving the cell wall.

According to the National Institute of Health, the best way to treat mycoplasma G is with the antibiotic azithromycin. This is the same antibiotic used to treat chlamydia, gonorrhea, and other respiratory infections. But, it’s important to note that doses for the three infections differ, and certain cases of Mg are becoming antibiotic-resistant. That’s why it’s so important to retest 3–4 weeks after treatment to ensure the bacteria has been eradicated. If azithromycin doesn’t work to treat Mg, the NIH suggests following up the treatment with a round of another antibiotic: moxifloxacin.

rainbow-colored chalk

Mycoplasma Genitalium and Antibiotic Resistance

Imagine a conversation like this:

Doctor: “Why did you come in today?”
Patient: Well, I’ve been having some unusual discharge and painful urination. I think it might be a case of chlamydia or gonorrhea because I recently got with a new partner.”
D: “Ah yes. I’ve heard of those. I’ll test you straight away.”
*2 very long weeks later*
D: “Well, we tested you for both chlamydia and gonorrhea and you were clear.”
P: “Well that’s great!”
D: “Yep! We also ran tests for the other common STDs and you didn’t have any of those either, so it may just be a UTI.”
P: “Ah yes, I’ve heard of that. Okay. that’s good because the symptoms have been lessening, so I’m guessing it’s just going away.”
D: “As UTI symptoms sometimes do. Okay. Well, we can give you some antibiotics for that UTI.”|
P: “Sounds great!”

And that does sound great…but it’s not. Here are two reasons why it’s actually really bad:

1. The patient doesn’t realize that they have an STD. They were not tested for the STD that they have, and they don’t even realize that there are more STDs to be tested for. They assume the doctor knows to test for all the STDs, but doctors won’t test for Mg unless specifically asked. Therefore, the patient will go out and continue having sex, spreading mycoplasma genitalium without even realizing that they have it.

2. The patient received antibiotics that will not treat their condition. Not all antibiotics are created equally, and different antibiotics must be used for different conditions. It would be impossible to treat Mg with the antibiotics used to treat a UTI. Amoxicillin is one of the main antibiotics prescribed to treat urinary tract infections, and it does so by dissolving the bacteria’s cell wall, which Mg doesn’t have. Plus, doctors are notorious for overprescribing antibiotics, which is leading to diseases becoming resistant to antibiotics. Yikes.

An alternative scenario to this is that the patient was found to have chlamydia and/or gonorrhea. This is actually a more likely scenario because Mgen tends to occur as an “opportunistic disease,” meaning that it typically appears when the immune system is weak or as a co-infection with another bacterial infection (like chlamydia or gonorrhea). In this case, the patient would receive antibiotic treatment for chlamydia or gonorrhea.

You might be thinking “Great! That’ll clear up the Mg too!” but you’d be wrong.

Chlamydia and Mg can be cured with the same antibiotics, but they require different doses. The dosage received would only be for chlamydia, which isn’t enough to get rid of Mg. Taking a small amount of an antibiotic or not finishing the course of antibiotics is a surefire way to make the bacteria antibiotic-resistant, which may be why there have been more and more cases of antibiotic-resistant mycoplasma genitalium popping up. For example, this study found that nearly two-thirds of all Mg-positive patients tested had a form of Mg that was associated with antibiotic resistance. Two Thirds! ⅔! 66%! More than half! However you say it, it’s a lot.

Your doctor is inadvertently making mycoplasma genitalium resistant to antibiotics by not testing you for it.

three flowes in three vases

What Does This All Mean?

There’s an STD that you’ve likely never been tested for, which also means you could have this STD and not know it. You may be thinking “who me?” to which we reply “YES, YOU!”

You, the person who gets checked for STDs religiously, every 3 months.
Or you, who’s been in a monogamous relationship with the same partner for 6 years.
Or even you, who’s never had sex with anybody before seeing their test results and sharing your own.

You could have mycoplasma genitalium and not even know it.

So what do you do? Get tested! If you’ve never been tested for Mg and you’re sexually active, you should get tested for it ASAP! You should especially get tested if you’ve ever had an STD in the past, since Mg is opportunistic, and tends to sneak in with other STDs while the door is left open (so to speak).

But don’t worry! The first thing to do is get tested so that you can know if you need treatment. The next thing is to get treatment if you need it, and the final step is to alert previous partners and retest at 4 weeks.

You have to be your own advocate when it comes to your health.

You can pretend like you didn’t read this. You can tell yourself that it’s not that big of a deal, and if it were you would’ve heard about it before. You can even tell yourself that there’s no way you have this STD, but all of that is wrong. You need to take control of your health. Now that you’ve learned about this new STD, it’s your responsibility to get tested for it!

Medically Reviewed by on November 4, 2019

Secure and Confidential
STD testing services

The fastest results possbile - available in 1 to 2 days

Cartoon of person with laptop at the STDcheck website
Categorized As
Author: Lauren Crain

Lauren Crain is a writer, designer, and joke-teller. With an academic background from Texas State University in communication and education, Lauren works tirelessly to find the best way to transform hard-to-grasp concepts into straightforward information. She's been a writer her whole life, but she began writing professionally in 2014. In 2018, she joined the editorial staff because of her passion for communicating information about public health and destigmatizing sexual health. Before becoming a member of the team, Lauren worked as a communication skills teacher, marketing coordinator, and freelance writer and designer. Her work has been featured on Forbes, The Muse, Insider,, Her Campus, and Business News Daily. When she's not researching, writing, or trying to communicate authentically, you can find her sitting outside.