What is Mycoplasma hominis? The Hidden Infection You Might Not Know

Estimated reading time: 8 minutes

Mycoplasma hominis is an extremely small bacterium that lacks a cell wall, making it different from most other bacteria. It often lives silently in the human reproductive system, affecting both men and women without showing noticeable symptoms.

Even though it may not cause discomfort, the infection can still spread through unprotected sexual contact, and in pregnant women, it can be passed to the baby during childbirth. Accurate testing, such as the PCR method, is therefore essential for early detection and proper treatment.

What is Mycoplasma hominis

Mycoplasma hominis is a very small bacterium that lacks a cell wall — a distinctive feature of the Mycoplasma group. Unlike most bacteria with rigid cell walls, it lives naturally in the human reproductive system, commonly found in the vagina, urethra, and sometimes in the upper urinary tract of both men and women.

In many cases, Mycoplasma hominis can exist in the body without causing symptoms. However, it can still be transmitted to others through unprotected sexual contact and may cause inflammation in the reproductive organs, especially in individuals with weakened immunity.

This organism is classified as a sexually transmitted infection (STI). Because it often causes no obvious symptoms, laboratory testing — particularly PCR (Polymerase Chain Reaction) — is the most accurate method for detecting its presence.

How is Mycoplasma hominis transmitted

Mycoplasma hominis is mainly transmitted through unprotected sexual contact — vaginal, oral, or anal. The bacterium enters the body via the mucous membranes of the reproductive tract and can persist silently without causing noticeable symptoms.

During pregnancy, the infection can be passed from mother to baby during childbirth, potentially leading to respiratory or urinary infections in newborns. Among adults, non-sexual transmission — such as sharing towels or using public toilets — is very uncommon.

Even in the absence of symptoms, an infected person can still spread the bacterium to their partner. Regular sexual-health screening and consistent condom use remain the most effective ways to prevent and reduce transmission of Mycoplasma hominis.

Mycoplasma hominis – Myths vs Facts

Many people mistakenly believe that Mycoplasma hominis is a harmless bacterium. In reality, it is classified as a sexually transmitted infection (STIs) and can spread even when there are no visible symptoms. Ignoring it or skipping regular checkups can increase the risk of unnoticed transmission.

A common misconception is that a simple blood test can detect this bacterium. This is incorrect — since Mycoplasma hominis lacks a cell wall, it cannot be detected through blood tests. The most accurate method is PCR (Polymerase Chain Reaction), which analyzes urine or genital secretions.

Another myth is that “no symptoms mean no infection.” In fact, most infected individuals do not show any signs but can still transmit the bacterium to their partners. Regular screening and consistent prevention practices are key to maintaining safe sexual health.

What infections are commonly found with Mycoplasma hominis

Mycoplasma hominis is often found alongside other bacteria in the reproductive tract, particularly Ureaplasma, Chlamydia trachomatis, and Gardnerella vaginalis. This condition, known as co-infection, can make inflammation more severe and treatment more complicated.

In many cases, patients diagnosed with Mycoplasma hominis are also unknowingly infected with additional pathogens. Therefore, testing for a single bacterium may not be sufficient. The Multiplex PCR technique allows for multiple infections to be detected in one test, improving both accuracy and treatment planning.

Comprehensive STD screening is recommended for individuals with sexual risk factors or a history of infection. It helps physicians provide complete care and reduces the chance of reinfection.

Symptoms of Mycoplasma hominis infection

Most people infected with Mycoplasma hominis show no noticeable symptoms, which is why the infection often goes undetected. However, in some cases, the bacterium can cause inflammation in the reproductive tract—especially when immunity is weakened or when co-infection with other pathogens occurs.

In women, possible signs include abnormal vaginal discharge with odor, itching, pelvic pain, or burning during urination. In more severe cases, the infection may spread upward, leading to pelvic inflammatory disease (PID).

In men, symptoms may include burning during urination, mild pain at the tip of the penis, or a clear discharge from the urethra. These signs can resemble non-gonococcal urethritis (NGU), which may not be detected by standard tests.

Anyone experiencing genital discomfort or unusual discharge should seek medical evaluation. Proper diagnosis helps rule out other causes and ensures appropriate treatment.

How is Mycoplasma hominis tested

Testing for Mycoplasma hominis involves collecting a urine sample or genital swab, which is analyzed in the laboratory using the PCR (Polymerase Chain Reaction) method. This technique is highly accurate for detecting bacteria that lack cell walls, such as Mycoplasma.

Before the test, it is recommended to avoid urinating for at least two hours to ensure sufficient bacterial concentration in the sample. Fasting or medication restrictions are generally unnecessary unless instructed by a doctor. Test results are typically available within a few days.

Modern laboratories also offer Multiplex PCR testing, which detects multiple pathogens—such as Mycoplasma, Ureaplasma, and Chlamydia—in a single test. This method is ideal for individuals with sexual risk factors, as it saves time and enhances diagnostic accuracy.

Treatment of Mycoplasma hominis and antibiotic resistance

Mycoplasma hominis infection is treated with antibiotics prescribed by a doctor. The choice of medication depends on the bacterial strain and laboratory results. Most treatments target the bacterial protein synthesis process because this organism lacks a cell wall, making drugs like penicillin ineffective.

In some cases, antibiotic resistance can occur, often due to incorrect drug use or stopping medication too early. If the infection persists, doctors may adjust the treatment regimen or switch to a more effective antibiotic, followed by a PCR retest to confirm recovery.

Successful treatment requires that both partners receive therapy simultaneously and abstain from sexual activity until completion. Following medical advice carefully helps prevent reinfection and ensures long-term recovery.

Effects of Mycoplasma hominis on fertility and pregnancy

Mycoplasma hominis infection can affect reproductive health, especially in women when left untreated for a long period. The bacterium can ascend from the vagina to the uterus or fallopian tubes, leading to pelvic inflammatory disease (PID), a major cause of infertility.

In pregnant women, the infection may increase the risk of preterm labor, amniotic fluid infection, or neonatal infections such as pneumonia and conjunctivitis. Doctors often recommend screening when abnormal discharge, pelvic pain, or a history of uterine inflammation is present.

In men, Mycoplasma hominis may impact sperm quality and contribute to infertility. Testing and treating both partners simultaneously is essential to restore reproductive health and prevent future complications.

How to prevent Mycoplasma hominis infection

Preventing Mycoplasma hominis infection starts with safe sexual practices. Always use condoms during vaginal, oral, or anal sex, as the bacterium spreads through direct contact with the mucous membranes of the reproductive tract.

Regular sexual-health checkups—at least once a year—are recommended, especially for those with multiple partners or a history of sexually transmitted infections. Because many cases are asymptomatic, preventive screening helps detect and treat infections early.

It’s also important that both partners receive treatment at the same time to prevent reinfection. Maintaining good personal hygiene and avoiding sharing personal items such as towels or underwear can further reduce the risk of transmission.

How much does a Mycoplasma hominis test cost

At Safe Clinic Bangkok, the cost of Mycoplasma hominis testing depends on the selected PCR package, a highly accurate molecular method that detects even small amounts of bacteria.

Two options are available:

• Urine PCR test for 7 STIs – 3,500 THB, including Mycoplasma hominis and other common infections.
• Urine PCR test for 15 STIs – 4,900 THB, recommended for those who prefer comprehensive screening for multiple pathogens such as Chlamydia and Ureaplasma.

All tests are conducted in certified laboratories under the supervision of experienced STD physicians. Results are available within a few days, and appointments can be booked online or via Safe Clinic’s official LINE account for convenience and privacy.

FAQ – Frequently Asked Questions about Mycoplasma hominis

Can Mycoplasma hominis go away on its own?

No. The infection usually does not clear up by itself. Even without symptoms, the bacterium can remain in the body and spread to others. Medical treatment with antibiotics prescribed by a doctor is the safest and most effective option.

Should I get tested even if I have no symptoms?

Yes. Testing is recommended for anyone who has had unprotected sex or whose partner tested positive. Mycoplasma hominis often causes no symptoms in the early stages, so preventive testing helps avoid long-term complications.

How long does it take to get test results?

With the PCR method, results are typically available within 3–5 working days, depending on the laboratory and the number of infections being tested at once.

Do both partners need to be tested?

Yes. Both partners should be tested and treated at the same time. Treating only one person can lead to reinfection, as the untreated partner may still carry the bacterium.

Can Mycoplasma hominis spread through sharing personal items?

The risk is very low. Transmission mainly occurs through direct mucosal contact during sexual activity. However, avoiding sharing personal items such as towels or underwear is still recommended for good hygiene.

Conclusion

Mycoplasma hominis is a common reproductive bacterium that often shows no symptoms until complications arise. Early detection through accurate PCR testing allows for timely treatment and reduces the risk of infection spreading.

Consistent condom use, regular sexual-health checkups, and testing with your partner are key preventive steps. For safe and private STD screening in Bangkok, Safe Clinic offers professional medical care and certified laboratory testing to ensure accuracy and confidentiality.

References

1. Horner P. Should we be testing for urogenital Mycoplasma hominis, Ureaplasma parvum and U. urealyticum? (IUSTI, review)
2. Horner P. Should we be testing for urogenital M. hominis and Ureaplasma? (PubMed record)
3. Jonduo M.E. et al. Adverse pregnancy and birth outcomes associated with genital mycoplasmas (systematic review, 2022)
4. Poku V.O. et al. The role of Mycoplasma hominis in maternal & neonatal health (review, 2022)
5. Sadeqi S. et al. Multiplex qPCR for C. trachomatis, M. hominis, U. urealyticum, M. genitalium (2022)
6. Chan J.L. et al. Rapid high-throughput multiplex PCR detecting M. hominis & Ureaplasma (2023)
7. Zhang S. et al. Azithromycin resistance in Ureaplasma urealyticum and M. hominis (2023)
8. Chen J. et al. CRISPR-Cas12a rapid assay for M. hominis (2022)

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