Ureaplasma is a group of small organisms belonging to the class Mollicutes, often found in the urogenital tract of both men and women. These organisms are frequently part of the normal microbial community in sexually active adults and usually do not cause issues. However, when their population increases significantly, they can transition from a harmless presence to a potential pathogen. This bacterium is increasingly recognized as a factor contributing to various health complications.
The Specific Bacterial Agents
The cause of a Ureaplasma infection is limited to two primary species: Ureaplasma urealyticum and Ureaplasma parvum. These two species were once grouped together but are now recognized as distinct organisms, distinguishable primarily through molecular testing. Both species lack a cell wall, which makes them inherently resistant to many common antibiotics, such as penicillin, that target cell wall synthesis.
Their minuscule size makes them among the smallest known free-living bacteria, requiring them to reside on the mucosal surfaces of the respiratory and urogenital tracts. A defining characteristic of the Ureaplasma genus is their reliance on the enzyme urease, which allows them to break down urea. This metabolic process generates ammonia as a byproduct, which is thought to contribute to inflammation and potentially lead to the formation of kidney stones in the urinary tract.
While both are present in the human microbiome, Ureaplasma urealyticum is more consistently associated with clinically significant diseases of the reproductive system. Ureaplasma parvum is more common, often acting as a harmless member of the urogenital flora, though it can become problematic when found in high concentrations.
Primary Mechanisms of Transmission
The most frequent way Ureaplasma is spread between people is through direct sexual contact. Transmission occurs during unprotected vaginal, oral, and anal sex, allowing the organism to colonize the urogenital tract, mouth, or rectum. Contact between the urinary and genital tracts during intimacy is the main route for its acquisition.
Beyond sexual activity, a significant mechanism of spread is vertical transmission, involving the passing of the organism from a mother to her offspring. This can happen either while the fetus is still in the uterus or as the baby passes through the birth canal during delivery. Exposure to the bacteria at birth can lead to the colonization of the newborn’s respiratory tract.
In rare cases, Ureaplasma may be acquired through non-sterile medical procedures or contaminated instruments, particularly in hospital settings. However, this is not a typical route for the general population.
Populations at Highest Risk
Individuals who have a greater number of sexual partners over time face an increased probability of Ureaplasma colonization and potential disease development. The frequency of sexual contact is a strong predictor of carriage, regardless of whether symptoms develop.
Co-infection with other sexually transmitted organisms, such as those causing chlamydia or gonorrhea, can also increase vulnerability to Ureaplasma overgrowth. The presence of multiple infections often disrupts the genital microbiome, creating an environment where Ureaplasma can proliferate and become symptomatic.
A compromised immune system is another major risk factor for developing an active Ureaplasma infection. People with immune deficiencies, such as those who have undergone organ transplantation or have certain congenital immune issues, are more susceptible to the bacteria spreading beyond the urogenital tract. Premature newborns also represent a highly vulnerable population due to their underdeveloped immune defenses, making them prone to severe, disseminated infection.
Manifestation of Infection
When Ureaplasma overgrows or invades host tissues, it can lead to a variety of clinical conditions in adults and cause serious consequences for newborns. In men, the infection is a known cause of urethritis (inflammation of the urethra). This condition is often categorized as non-gonococcal urethritis (NGU) when other common bacteria are ruled out. Symptoms may include a burning sensation during urination, a clear or cloudy discharge from the penis, or urethral itching.
In women, the infection is associated with conditions affecting the lower and upper reproductive tract. Ureaplasma has been linked to cervicitis (inflammation of the cervix) and can also contribute to bacterial vaginosis (BV) by disrupting the normal vaginal flora. If the infection ascends, it may result in pelvic inflammatory disease (PID), a condition that can cause chronic pelvic pain and increase the risk of infertility or ectopic pregnancy.
For pregnant women and their babies, the consequences of Ureaplasma infection are particularly concerning. The presence of the bacteria in the uterus can cause inflammation of the fetal membranes, known as chorioamnionitis. This inflammation is strongly associated with adverse pregnancy outcomes, including the premature rupture of membranes and spontaneous preterm birth.
Newborns who acquire the organism, especially those born prematurely, face the most severe risks. The infection can lead to congenital pneumonia, bacteremia, and meningitis, which can be life-threatening. Ureaplasma has also been implicated in the development of bronchopulmonary dysplasia, a chronic lung disease that affects the underdeveloped lungs of premature infants.