When it comes to your vaginal health, understanding the different types of bacteria that live in your body is crucial. Among the many microorganisms that inhabit the vaginal microbiome, some get a lot of airtime, and some fly under the radar. One such lesser-known bacterium is Mycoplasma hominis. 

Mycoplasma species are notoriously hard to study (more on that below), so even though researchers discovered them decades ago, there’s still a lot we don’t know about them. For now, we break down the available literature we have on what Mycoplasma hominis is, how it affects your vaginal health, and what it means if it shows up in your Evvy test results.

What is Mycoplasma?

Mycoplasma is a unique type of bacteria, classified as a mollicute. Unlike most bacteria, mollicutes don't have a cell wall, which gives Mycoplasma bacteria some interesting characteristics. For example, they don’t show up on Gram stains, a common lab test used to identify bacteria at infection sites. Mycoplasma bacteria are also very small and slow-growing, making it tricky to detect or study in a lab.

In the vaginal microbiome, there are three main species of Mycoplasma: 

Mycoplasma genitalium is considered a sexually transmitted infection (STI), while the other two species are considered “opportunistic pathogens”. This means they're usually harmless but can contribute to infections under certain conditions — though they don’t act alone. While it’s true that Mycoplasma has been linked to various diseases, it hasn’t been definitively proven to cause them on its own. Remember: correlation doesn’t mean causation!

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Mycoplasma hominis

Of the Mycoplasma species, Mycoplasma hominis is the most commonly found in women of reproductive age. It's present in up to 50% of women's urinary tract and genital tract. 

For many women, Mycoplasma hominis doesn’t cause any symptoms or problems. It’s a part of the natural flora in the body, much like other bacteria that live in harmony with us. However, under certain circumstances, this bacterium can contribute to infections or complications, particularly in the reproductive and urinary systems.

Mycoplasma hominis is particularly interesting because it tends to appear in higher quantities in people who have bacterial vaginosis (BV) — a common condition caused by an imbalance of bacteria in the vagina. When other BV-associated bacteria are present, levels of Mycoplasma hominis can increase by up to 10,000 times.

Mycoplasma hominis has also been associated with trichomoniasis, a sexually transmitted infection caused by the parasite Trichomonas vaginalis. Research suggests that Mycoplasma hominis might help Trichomonas adhere more effectively to vaginal epithelial cells (the cells that line the vaginal wall), which could contribute to the infection.

Should Mycoplasma hominis be treated?

Here’s where things get a bit more nuanced. Despite its association with conditions like BV and trichomoniasis, Mycoplasma hominis is considered a commensal organism, meaning it typically doesn’t cause problems on its own. Instead, it just hangs with a bad crowd. However, treating Mycoplasma hominis directly isn’t likely to solve the underlying issue if it’s part of a larger imbalance in your vaginal microbiome.

Current research suggests that rather than targeting Mycoplasma hominis specifically, it’s more effective to treat the underlying infection, such as BV. As the levels of other problematic bacteria like Gardnerella and Prevotella decrease, the levels of Mycoplasma hominis usually decrease too. This is because certain BV-associated bacteria are more likely to contribute to symptoms due to their specific characteristics that trigger an immune response — something Mycoplasma hominis generally doesn’t do.

What if Mycoplasma hominis shows up in your test results?

If you see Mycoplasma hominis in your Evvy test results, it’s important not to panic. While the presence of this bacteria can indicate that there might be other disruptive bacteria in your vaginal microbiome, it doesn’t necessarily mean you need immediate treatment for Mycoplasma itself. 

Think of Mycoplasma hominis as an “indicator species.” High levels of it might suggest that there are also high levels of BV-related organisms, while lower levels could indicate that your vaginal microbiome is mostly balanced. Either way, your Evvy test results will give you a comprehensive overview of what bacteria and fungi are in your vaginal microbiome. 

The key is to look at the full picture. Understanding all the species of bacteria and fungi in your vaginal microbiome will help you and your healthcare provider focus on the right problem. This is where a comprehensive test like the Evvy test can be incredibly useful. Such tests provide detailed information about what’s happening microbially in your vagina, including whether certain bacteria are protective or disruptive, existing research on these bacteria, and context around effective treatments.

FAQ

What causes Mycoplasma hominis?

Mycoplasma hominis is a type of bacteria that naturally lives in the vaginal microbiome and urinary tract. It's considered part of the body's normal bacteria and is usually harmless. However, certain situations can cause Mycoplasma hominis to multiply. Normally, the vaginal and urinary tracts have a balanced mix of bacteria. When this balance is disrupted — like in the case of bacterial vaginosis — it can allow Mycoplasma hominis to grow more than usual. While Mycoplasma hominis isn’t considered a sexually transmitted infection, it can be passed between partners through sexual contact, especially if unprotected. A weakened immune system, due to illness, medication, or other factors, can make it harder for the body to control Mycoplasma hominis, leading to potential overgrowth and infection.

Does Mycoplasma hominis need treatment?

Current research suggests that treating the underlying infection, such as BV or trichomoniasis, is more effective than targeting Mycoplasma hominis specifically. Mycoplasma hominis is known as a "commensal" bacteria, which means it's usually present when other disruptive bacteria are present but unlikely to cause symptoms on its own.