Mycoplasma: guilty, an accomplice, or just a bystander?

The story of a medical investigation into genital infections

When a vaginal or cervical swab result comes back positive, one question often comes up:

“Is this bacteria dangerous? Is it responsible for my symptoms?”

With Mycoplasma, the answer is not always straightforward.

Because in medicine, detecting a microorganism does not automatically mean that it is causing disease.

To understand this better, imagine a police investigation…

The story of Mycoplasma and the jewelry store investigation

Imagine:

I am Mycoplasma.

I like jewelry.

Not because I want to steal it… I simply like spending time in jewelry stores.

So I often visit a large jewelry store.

One day, a robbery occurs.

The police arrive.

And who do they find at the scene?

Me: Mycoplasma.

And right next to me:

Chlamydia.

The police already know Chlamydia.

Because Chlamydia is known to rob jewelry stores.

The investigators then start noticing something:

Several times, when Chlamydia is found during a robbery…

Mycoplasma is also present at the scene.

So a question arises:

“Is Mycoplasma also a thief?”

Am I automatically guilty just because I am often found in the same place as Chlamydia?

No.

Maybe:

• I am truly involved in the robberies;

• I help Chlamydia;

• I make its work easier;

• or maybe I am simply present in the same place without being responsible.

To answer this question, investigators must ask something essential:

Does Mycoplasma also rob jewelry stores when it is alone?

And this is exactly the question medicine is trying to answer.

In medicine: association does not always mean causation

When a laboratory detects a bacterium, it answers one question:

“Is this bacterium present?”

But medicine must answer another:

“Is this bacterium responsible for the disease?”

These are two different questions.

A microorganism can be:

• a true pathogen;

• a contributing factor;

• a companion found together with other bacteria;

• or simply a colonizer present without causing disease.

  
  

Chlamydia: the already identified thief

Chlamydia trachomatis is one of the best-studied sexually transmitted infections in gynecology.

We know that it can:

• remain silent for a long time;

• cause cervicitis;

• ascend toward the uterus and fallopian tubes;

• lead to pelvic inflammatory disease (PID).

Chlamydia-related PID can cause complications such as:

• chronic pelvic pain;

• tubal adhesions;

• increased risk of tubal infertility.

In our story:

Chlamydia is the thief already known by the investigators.

Mycoplasma genitalium: the new serious suspect

Now let’s talk about Mycoplasma genitalium.

For many years, this bacterium was less recognized.

Today, scientific evidence shows that it is not simply a bystander.

Mycoplasma genitalium is recognized as a sexually transmitted infection (STI).

It is associated with:

• cervicitis;

• urethritis;

• pelvic inflammatory disease (PID).

Several studies have shown an association between M. genitalium infection and an increased risk of PID.

A systematic review and meta-analysis by Lis and colleagues found a significant association between M. genitalium infection and female reproductive tract disease.(Lis R et al. Mycoplasma genitalium infection and female reproductive tract disease: a systematic review and meta-analysis. Clinical Infectious Diseases, 2015.)

The CDC also recognizes M. genitalium as a pathogen associated with cervicitis and PID and provides specific recommendations regarding testing and treatment in selected clinical situations.

However, important questions remain:

• What proportion of PID is caused exclusively by M. genitalium?

• Should every positive test result be treated?

• How much does treatment reduce long-term complications?

Research is ongoing.

But be careful: not all Mycoplasma are the same

The word “Mycoplasma” includes several different bacteria with very different behaviors.

This is a common source of confusion.

Mycoplasma genitalium: a suspect with evidence

In our investigation:

Mycoplasma genitalium is the suspect for whom investigators have found many clues.

Evidence shows that it can contribute to certain genital infections.

It therefore deserves appropriate medical management.

Mycoplasma hominis: the suspect who has not been convicted

Now let us introduce another character:

Mycoplasma hominis.

It can also be detected on laboratory testing.

It can also be present at the “crime scene.”

But the story is different.

Mycoplasma hominis can be found in people without symptoms.

Its presence alone does not prove:

• that it is causing an infection;

• that it explains symptoms;

• that it is responsible for PID.

In our investigation:

Mycoplasma hominis is more like a person frequently seen in the jewelry store… but without enough evidence to accuse them of the robbery.

What do scientific societies say?

The European STI Guidelines Editorial Board published an important position regarding:

• Mycoplasma hominis;

• Ureaplasma parvum;

• Ureaplasma urealyticum.

Their conclusions:

• asymptomatic carriage is common;

• detection alone does not necessarily mean disease;

• routine screening and treatment of asymptomatic individuals are not recommended.

(Horner P et al. Should we be testing for urogenital Mycoplasma hominis, Ureaplasma parvum and Ureaplasma urealyticum in men and women? Journal of the European Academy of Dermatology and Venereology, 2018.)

And what about Ureaplasma?

Ureaplasma species are also frequently found in the genital microbiome.

Their role in genital infections in adults remains debated.

A positive result alone does not automatically mean that treatment is required.

As always:

a test result must be interpreted in its clinical context.

Why does this difference matter?

Because a positive test result can create a lot of anxiety.

Some people immediately think:

“I have a serious infection.”

or:

“My partner must have recently transmitted something to me.”

But medical reality is more complex.

A biological result must always be interpreted together with:

• symptoms;

• clinical examination;

• other test results;

• medical history;

• relationship context.

  
  

Medicine is not a search for someone to blame

In our story:

• Chlamydia is a known thief.

• Mycoplasma genitalium is a suspect with increasingly strong evidence.

• Mycoplasma hominis is often a witness found at the scene, but without enough evidence to accuse it routinely.

Medicine does not only look for a microorganism.

It seeks to understand its role.

Because being found in a jewelry store…

does not necessarily mean you robbed the jewelry store.

Key points

• Mycoplasma genitalium is a recognized STI and can cause certain genital infections.

• Mycoplasma hominis does not have the same status, and its presence alone does not prove disease.

• Not every positive test result automatically requires treatment.

• A medical diagnosis is based on the whole clinical picture, not only the name of a bacterium.

The most important question is not only:

“Which microorganism did we find?”

The real question is:

“What role does this microorganism actually play in this specific situation?”

Kindly yours,

Dr Sandra Yene Amougui