Last updated: 11/2/2022

Editor's Note: Below Evvy's Senior Scientist, Dr. Krystal Thomas-White, shares a scientist's perspective on Mycoplasma, reviewing existing research on Mycoplasma and pointing out the gaps between what is known and unknown. Dr. Thomas-White got her PhD in microbiology and immunology from Loyola University Chicago where her research was focused on understanding the connection between the bladder and vaginal microbiomes in urogenital (urinary + genital) disorders. 

Everything comes back to bacteria. I’ve always been fascinated by it: the way it affects each part of our lives, despite being invisible to the human eye; its diversity; and its versatility. There isn’t anything bacteria can’t do. 

Luckily, I get to hang out with bacteria every day! As Senior Scientist at Evvy, I spend my time combing through research papers, searching for the root causes of vaginal disorders, and talking to our community about the conditions and symptoms that affect them most. 

Now that you know how much I love bacteria, you’ll understand why I was excited when I heard that so many other people in the vaginal health community are interested in learning more about the smallest, free-living, self-replicating bacteria that we know of: Mycoplasma

Why are so many people fascinated with this tiny bacterial genus and its relationship to vaginal health? And what is important to understand about it from a scientific perspective? I give a ‘who, what, where, and why’ overview and some of the most common questions about Mycoplasma circulating online below. 

What is Mycoplasma

Mycoplasma is a type of bacteria known as a Mollicute. Like Ureaplasma, another Mollicute, Mycoplasma also happens to be kind of unique in the microbial world. It is the smallest, free-living, self-replicating bacteria that we know of.

Mycoplasma has no cell wall, so it doesn’t appear on Gram stains (a quick test using a microscope that checks for bacteria at the site of a suspected infection) and is often very slow growing. These two qualities mean it can be difficult to detect.

Mycoplasma and the vaginal microbiome 

Can Mycoplasma be the root cause of infections like bacterial vaginosis, yeast infections, and UTIs? 

Based on the existing research, it’s unlikely. There are three species of Mycoplasma that are predominantly found in the vaginal microbiome: Mycoplasma genitalium, Mycoplasma hominis, and Mycoplasma girerdii

With the exception of M. genitalium (more on that below), most Mycoplasma are considered “opportunistic pathogens”, meaning that they are normally harmless and only cause infections under certain conditions. What that means is that Mycoplasma has been associated with a lot of diseases, but has never been shown to be the cause of those diseases. 

Let’s talk about the most commonly found Mycoplasma, M. hominis before we get into the other species later on.  

M. hominis

Around 20-50% of reproductive age women have M. hominis in their vaginal microbiome. 

M. hominis tends to be found in people who have bacterial vaginosis (BV), and increases up to 10,000 times when other BV-associated bacteria are present

It has also been associated with trichomoniasis. Notably it’s been shown to improve Trichomonas adhesion to vaginal epithelial cells  (the cells that make up the vaginal wall). 

But here’s the most important part: it’s commensal, meaning that it does not seem to act out on its own, but rather follows the crowd — if it’s alongside disruptive bacteria, it acts disruptive. Treating the Mycoplasma hominis likely won’t do anything to rid of the disruptive bacteria it’s latching onto, just like getting rid of barnacles on a whale won’t do anything if the problem is the whale. 

The research today supports that focusing on treating the overall infection (e.g. bacterial vaginosis) completely (getting to a place where your microbiome is dominated by protective microbes with low levels of pathogenic like Gardnerella vaginalis, Prevotella, etc.) is more likely to get rid of your symptoms than just treating Mycoplasma hominis

Why? Remember how I said I love bacteria for its diversity and versatility? Certain other BV-associated bacteria like Prevotella and Mobiluncus are more likely to be contributing to symptoms than Mycoplasma hominis because of their specific abilities and characteristics to cause an immune response —characteristics Mycoplasma hominis simply doesn’t have. We also have much more data and research to back up that bacteria like Prevotella and Mobiluncus cause symptoms than we do M. hominis (although the research is evolving!).  

Does Mycoplasma cause recurrent vaginal infections? 

Currently, there is no research to suggest Mycoplasma causes recurrent vaginal infections. 

If you are experiencing recurrent infections, such as bacterial vaginosis, it’s possible that there is a presence of biofilm, a sticky, film-like web created by certain pathogens to maintain their hold in the vaginal microbiome.

You can think of this film as a structure that offers bacteria protection from their environment and any external threat to their survival (like antibiotics or the lactic acid produced by protective Lactobacillus bacteria)! 

Research suggests that some of the disruptive microbes, like Gardnerella, found in your vaginal microbiome and associated with BV can produce biofilm. To tie things back to our conversation about Mycoplasma, there is no current research to support that Mycoplasma contributes to biofilm formation.

Many vaginal health experts believe that biofilm formation in the vaginal microbiome is one of the key reasons why vaginal infections persist and/or recur! 

What should I do if there is Mycoplasma in my Evvy results?

Let’s start off by saying that everything treatment-related should be a conversation with your doctor! 

While Mycoplasma has been shown to live alongside other pathogens in the vagina, there is little to no research supporting the idea that Mycoplasma alone causes symptoms, let alone at what percent abundance treatment is necessary. 

Most of the experts Evvy has talked to share the belief that there is no universal guidance around whether or not these microbes should be “treated” at all, and any treatment should be determined on an individual basis. 

You can think of Mycoplasma as an “indicator species”. Meaning that if it is there in high amounts, then it is likely that other disruptive bacteria are there as well. Remember, levels of M. hominis increase as levels of Gardnerella increase. So high levels of Mycoplasma might be a sign that there are also high levels of BV-related organisms. Whereas lower levels might indicate that your microbiome is mostly fine, and Mycoplasma is just hanging out with the lactobacilli. 

The important part to get a full picture of all the species of bacteria and fungi in your vaginal microbiome — so you can make sure to focus on the right problem!

This is easy to do with an Evvy test, which tells you what’s happening microbially in your vagina. Our results also provide context for each species of bacteria including if they’re protective or disruptive, existing research, and context around effective treatments. Then you can talk to your doctor about a care plan that works best for you, your body, and your unique vaginal microbiome.  

Recurrent symptoms? Meet Evvy's at-home vaginal microbiome test, approved by leading OB-GYNs.
Learn more

Is Mycoplasma an STI? 

It depends on the species. 

M. genitalium

M. genitalium is the only one of the Mollicutes recognized as an STI by the CDC. In men it can cause non-gonococcal urethritis (NGU) - basically painful infection of the urethra. Most cases of NGU are caused by other STIs like Chlamydia or trichomoniasis, but 15-20% of cases in men are caused by M. genitalium.

It is uncommon for women to get NGU, therefore it is not considered an STI in women. However, M. genitalium can cause other problems in people with vaginas. 

A meta-analysis of studies done in women found that the presence of M. genitalium is associated with cervicitis, pelvic inflammatory disease (PID), and preterm birth

We know that reading those words together may feel daunting, but it’s not meant to scare you. M. genitalium is fairly rare: only 0-5% of women have it

If you do find out that you have M. genitalium in your vaginal microbiome, it’s important to know two things. First, an association between a microbe and a condition is not a diagnosis! Having M. genitalium in your microbiome does not mean you will develop those conditions. Also, due to lack of research (hat tip to the gender health gap), it is unclear if treating M. genitalium changes outcomes for women!  We recommend talking to your doctor about if and what treatment is right for you.

Should I be worried about Mycoplasma girerdii and other species? 

Mycoplasma girerdii

M. girerdii has associations with the STI Trichomonas. Trichomonas is a parasite (a multicellular organism) that other bacteria will attach to for survival. This species of Mycoplasma has only been found in patients with Trichomonas, not in healthy individuals. Like Mycoplasma hominis, M. girerdii has been shown to improve Trichomonas’ attachment to vaginal epithelial cells.

TLDR: research suggests that treating Trich will most likely remove the M. girerdii as well.

Other Mycoplasma species:

There are other Mycoplasma species that are less well studied but they are all thought to be benign. These include: 

  • Mycoplasma amphoriforme
  • Mycoplasma fermentans
  • Mycoplasma penetrans, Mycoplasma pirum
  • Mycoplasma primatum 
  • Mycoplasma spermatophilum

Why are people talking so much about Mycoplasma

Like its cousin Ureaplasma, Mycoplasma has long been included on PCR-based tests for STIs. Because they are included in STI panels, it sometimes leads to the assumption that all Mycoplasma (rather than just M. genitalium) are STIs, but the science doesn’t back that up

Sadly, this is not the only problem with diagnostic tests for urogenital health. Existing tests simply don’t look at the whole picture. So instead doctors and patients are left with making the best guess possible given the information provided. And if that information is flawed or biased, then the conclusions will be flawed or biased as well. 

Inadequate testing is one of the many reasons why Evvy exists and I feel my work here is so important. The consequences of today’s limited vaginal health standards—physical discomfort and emotional exhaustion, to name a few —lead to a lower quality of life than we deserve. 

Treating Mycoplasma

It’s completely understandable to gravitate towards treating something that sounds suspicious when nothing else has worked. Mycoplasma is something we can test for and it offers a novel answer (though not necessarily the right one) to mystery vaginal symptoms that are horribly uncomfortable and, not reacting to treatments, and may not have an identifiable cause. 

You may hear reports online of people who treated Mycoplasma and got better. And believe it or not, that makes sense. As I said before Mycoplasma is an indicator species. So if levels of Mycoplasma are high, chances are other disruptive organisms are as well. Remember, antibiotics are not very targeted. One antibiotic can kill off a wide range of different organisms. 

So, If you took an antibiotic and your symptoms went away and your levels of Mycoplasma went down, chances are that you accidentally treated the underlying cause without realizing it. As all the disruptive microbes went down, so too did Mycoplasma

For these people, we are happy that the treatment worked! But we want to caution that just because it worked doesn’t mean Mycoplasma was the cause of the symptoms (correlation does not equal causation). It’s like if someone cuts out gluten because they want to lose weight. If they end up losing weight, they may attribute it to not eating gluten, but in reality, it’s likely because they are eating fewer simple carbohydrates and processed foods. 

Case in point, it’s important to understand what the scientific research currently states, especially before undergoing potentially unnecessary treatment (as that can further irritate or imbalance your microbiome!)