Is Ureaplasma an STI?
By James Myhre & Dennis Sifris, MD Published on January 11, 2024
12–16 minutes
Ureaplasma is a genus of bacteria that primarily infects the genitals and urinary tract. It can be passed through sexual contact but is not considered a
sexually transmitted infection (STI) because of its low degree of pathogenicity (capacity to cause disease).
It is estimated that a large proportion of the sexually active population is infected with
Ureaplasma without it causing any symptoms. However, when a person's
immune system is low and the bacterium overgrows, it can cause urethritis (inflammation of the urethra) or bacterial vaginosis and possibly contribute to infertility.
Some infections will clear up on their own; others need to be treated with a course of antibiotics.
This article explains what
Ureaplasma is, including the symptoms, modes of transmission, and methods of diagnosis. It also explains how infections are prevented and treated and the possible complications of an untreated infection.
Milko / Getty Images
What Does "Ureaplasma-Positive" Mean?
Ureaplasma belongs to a class of bacteria known as mycoplasma. These are the smallest self-replicating organisms known in nature and ones that tend to be commensal in the human body (meaning cohabitate with other organisms without causing damage).1
There are two major strains known as
Ureaplasma urealyticum and
Ureaplasma parvum.2
How Common Is Ureaplasma?
Females (people with a vagina) appear more vulnerable to Ureaplasma infections than males (people with a penis). Studies suggest that infection rates may be as high as 40% to 80% in females and up to 50% in males.2
Once infected,
Ureaplasma will inhabit
mucosal tissues of the genital and urinary tract but usually are well controlled by the immune system, causing little if any harm. As such, testing positive for the
Ureaplasma in and of itself does not mean anything.
It is only when the bacteria overgrows and establishes a symptomatic infection that a person may need treatment. An active infection may also place a person of any sex at an increased risk of infertility.
Ureaplasma Symptoms
If
Ureaplasma is well-controlled and living in check with other organisms in the
genital microbiome, it will not cause any symptoms. In fact, the vast majority of
Ureaplasma infections are
asymptomatic (without symptoms) and may never cause any symptoms.2
However, if the immune system cannot control the bacterium,
Ureaplasma can overgrow and establish a symptomatic infection in the urinary and/or genital tract. This can lead to infections known as
nongonococcal urethritis (NGU) or
bacterial vaginosis (BV).3
Nongonococcal Urethritis
Urethritis is inflammation of the
urethra (the tube through which urine exits the body). Nongonococcal urethritis occurs when the inflammation is caused by something other than
gonorrhea.4
While STIs like
chlamydia are the most likely causes, NGUs can also be caused by viruses, bacteria, fungi, and parasites that are not exclusively transmitted by sex.5
Studies vary, but some suggest that the incidence of
Ureaplasma in people with NGU ranges from 32% to 44%.6
Common symptoms of NGU include:4
- Pain or burning with urination
- A clear or creamy, foul-smelling discharge
- Urethral itching
- Frequent or urgent need to urinate
People with a penis may also experience
balanitis (inflammation of the penis head) or
posthitis (inflammation of the foreskin),7 while people with a vagina may experience
cervicitis (inflammation of the cervix) and vaginal bleeding.8
Bacterial Vaginosis
Bacterial vaginosis is a common condition in which the balance of bacteria in the vagina gets out of sync. Symptoms tend to be mild but can be persistent and difficult to treat.9
Common symptoms of BV include:9
- Vaginal itchiness, redness, and swelling
- A thin gray, white, or greenish vaginal discharge
- Burning sensations when urinating
- A "fishy" vaginal odor
- Pressure or heaviness in the pelvis
While many people with BV are asymptomatic, studies suggest that those with
Ureaplasma are 4 times more likely to experience symptoms compared to other common bacteria types.10
Understanding Ureaplasma Transmission
Ureaplasma can be passed through sexual contact, including vaginal, oral, and anal sex. Although the vagina and penis are common sites of infection,
Ureaplasma can also inhabit the mouth11 and rectum,12 though they don't typically cause any symptoms.
Ureaplasma can also be passed to a fetus or newborn during pregnancy. This can occur while the fetus is in the
uterus (womb) or as it passes through the birth canal during delivery.13 The rate of
Ureaplasma transmission from birthing parent to child is 15% to 88%.14
How to Get Tested for Ureaplasma
Ureaplasma infection can be diagnosed with a urine sample or a
swab of fluid from the vagina or urethra. The bacteria can be detected with
polymerase chain reaction (PCR), a test that is able to multiply even small amounts of an organism's genetic material (DNA) to detectable levels.
The test is highly accurate, with a
sensitivity of 96.5% and specificity of 93.6%.15 (Sensitivity refers to a test's ability to return a true positive result, while specificity is the ability to return a true negative result.) Results can usually be returned within 36 hours.15
The PCR can also be used to detect
Ureaplasma in the mouth, throat, rectum, and eyes.
At-Home Ureaplasma Test Kits
At-home tests are available to detect
Ureaplasma alone or as part of a panel of STIs. The cost of these tests is between $100 and $250.
The tests allow you to take a genital swab in the privacy of your home and mail it to a lab for testing. The results are usually returned via a secure website within two to three business days.
Should My Partner Get Tested?
If you test positive for
Ureaplasma during a symptomatic infection, your partner can also be tested or simply be treated under the presumption that they have
Ureaplasma.16
Outside of a symptomatic infection, the Centers for Disease Control and Prevention (CDC) does not recommend routine testing as the implication of a positive result may be negligible. In the end, having
Ureaplasma does not mean that you will ever have symptoms or any health concerns.
The only exceptions may be for males who experience unexplained recurrent NGUs or females with unexplained recurrent cervicitis. In such cases, testing can help determine if
Ureaplasma is the cause and direct the appropriate course of treatment.
Ureaplasma Antibiotics
As with any acute bacterial infection, the primary form of treatment for a symptomatic
Ureaplasma infection is
antibiotics. Even so, the treatment can be challenging due to the unique structure of the bacteria, which lacks a cell wall.
This makes certain antibiotics, like
penicillins, ineffective against
Ureaplasma because they work by blocking the formation of the cell wall as a bacterium multiplies, causing it to collapse and die.17
Because of this unique feature,
Ureaplasma and other mycoplasma bacteria require specific antibiotics to control the infection. These are taken orally (by mouth) and dosed in milligrams (mg).
The CDC currently recommends the following treatment regimens for mycoplasma
-induced NGU and cervicitis, including
Ureaplasma:18
| Condition | Recommendation | Antibiotic Therapy |
|---|
| Urethritis | Preferred | Doxycycline 100 mg twice daily for seven days |
| Alternative | Azithromycin 1 gram (1,000 mg) in a single dose or azithromycin 500 mg in a single dose, followed by 250 mg daily for four days |
| Cervicitis | Preferred | Doxycycline 100 mg twice daily for seven days |
| Alternative | Azithromycin 1 gram (1,000 mg) in a single dose |
In newborns, azithromycin can also be used. To prevent transmission of the bacterium, the drug may also be given to the pregnant person during the pregnancy either by mouth or intravenously (into a vein). Consultation with a specialist
obstetrician is needed to make an informed choice.13
Can Ureaplasma Go Away On Its Own?
Oftentimes,
Ureaplasma infections will go away on their own without treatment, though antibiotics may be prescribed to speed the process.
With that said, studies have shown that certain mutations of the bacteria can evade immune detection and either persist or recur.19 Because of this, people with recurrent unexplained
urinary tract infections should undergo testing to determine if
Ureaplasma is the cause.
Complications of Untreated Ureaplasma
There is even evidence, though not conclusive, that
Ureaplasma may cause unexplained infertility in some people.20 ("Infertility" is defined as the inability to conceive after trying for 12 months.)
This has been verified in studies in which
Ureaplasma urealyticum is seen more frequently in females with unexplained infertility.21 Although study findings are inconsistent,
Ureaplasma is also linked to
pelvic inflammatory disease (PID), a condition that can also increase the risk of infertility.22
In males, Ureaplasma (particularly
Ureaplasma parvum) appears to lower not only the
sperm count but also the proportion of forward-moving sperm cells.23
Whether the infection alone is the cause of infertility is unknown. What is known is that recurrent NGU or cervicitis can independently increase the risk of infertility despite the type of causative agent.18
Pregnancy Complications
Ureaplasma can affect a pregnancy, causing
preterm birth (meaning birth before 32 weeks of gestation).
Ureaplasma parvum is the species most commonly associated with this.13
A 2014 study from the University of Maryland School of Medicine found that nearly half of all preterm births involved birthing parents with
Ureaplasma. In such cases, the transmission occurred in utero (while in the uterus), causing infection in either the
respiratory tract,
nervous system,
digestive tract, or multiple organ systems of the fetus.13
Infection in these organs can lead to potentially severe complications in preterm babies, including:13
- Bronchopulmonary dysplasia (BPD): A form of lung disease in newborns that damages the tiny air sacs of the lungs (alveoli)
- Necrotizing enterocolitis (NEC): A potentially life-threatening condition in preterm babies in which bacteria start to destroy the digestive tract
- Hemorrhagic hydrocephalus (HH): The accumulation of fluid in the brain that causes potentially devastating bleeding
While exposure to
Ureaplasma on its own does not cause these complications—other factors such as
low birth weight and being born before 29 weeks can contribute—an infection in newborns is independently linked to a fourfold increased risk of BPD, a three-fold increased risk of NEC, and a 2.5-fold increased risk of HH.13
Other Complications
In adults, it is uncommon for
Ureaplasma to disseminate (spread) and cause complications outside of the urinary and genital tracts. Even so, people who are severely immunocompromised are vulnerable to complications.
Among this group, rare complications have been reported, such as :
- Recurrent skin and soft-tissue infections24
- Kidney abscesses25 and pyelonephritis (a kidney infection)26
- Gastrointestinal abscesses27
- Empyema (a collection of pus between the lungs and surrounding membrane)27
- Brain abscesses (causing neurological symptoms such as hearing loss and loss of balance)28
Severely immunocompromised people who experience these events—including organ transplant recipients and those with
advanced, untreated human immunodeficiency virus (HIV)—should be tested for
Ureaplasma to ensure the correct treatment is delivered.
Ureaplasma Prevention and Reinfection
Because
Ureaplasma often causes no symptoms, it is possible to be reinfected without knowing. It is unclear if repeated infection poses any health concerns in the absence of symptoms.
On the other hand, recurrent NGU and cervicitis do pose health risks. So, the avoidance of reinfection is essential—particularly if you are trying to get pregnant.
If you have been diagnosed with
Ureaplasma, you can take steps to reduce your risk of reinfection:
- Take antibiotics as prescribed and to completion even if you feel better.18
- Abstain from sex until you and your partners have been treated.18
- Given the high rate of reinfection, it is important to get retested after three months, regardless of whether partners have been treated.18
- Use condoms correctly and consistently.29
- Reduce your number of sex partners.29
- Avoid douching, which can strip away the protective mucus barrier and increase your susceptibility to infection.18
Summary
Ureaplasma is a bacteria that can be passed through sex but is not a sexually transmitted infection because it can reside in the urinary and genital tracts without causing any symptoms. It can also be passed from birthing parent to child during pregnancy or delivery.
On occasion,
Ureaplasma can overgrow and cause infections like nongonococcal urethritis or cervicitis. Possible complications include infertility and preterm birth.
Ureaplasma can be detected with a urine sample or swab of vaginal or urethral fluid. The infection may clear on its own or with a course of antibiotics, typically doxycycline or azithromycin.
