Mycoplasma spreads from person to person, but the exact route depends on which type of mycoplasma you’re talking about. The two most common species that infect people are Mycoplasma pneumoniae, which causes respiratory illness, and Mycoplasma genitalium, which is a sexually transmitted infection. Both spread through direct close contact with an infected person, and both can be passed along by someone who has no symptoms at all.
Respiratory Mycoplasma: Spread Through Breathing
Mycoplasma pneumoniae travels in tiny respiratory droplets. When someone with the infection coughs or sneezes, they release droplets containing the bacteria into the air. You get infected by breathing those droplets in. This means close, prolonged contact is usually required. A brief encounter with a stranger is far less risky than spending hours in the same room with an infected family member, classmate, or coworker.
Outbreaks tend to happen in crowded environments where people share air for extended periods: schools, college residence halls, nursing homes, and military barracks. These settings create ideal conditions because the bacteria can move easily between people who are in close quarters day after day. Making things worse, the incubation period for respiratory mycoplasma is long, often one to three weeks, which means someone can be contagious and spreading bacteria well before they realize they’re sick.
Carriers Can Spread It for Months
One of the trickiest aspects of respiratory mycoplasma is that people can carry and shed the bacteria without ever developing symptoms. Research published in The Lancet’s eBioMedicine found that M. pneumoniae carriage can last several months and is, on its own, completely asymptomatic. That means a person who feels perfectly fine can still pass the bacteria to others over a long stretch of time. This silent shedding is a major reason outbreaks in schools and group living situations can drag on for weeks or even months before they’re recognized.
Sexual Mycoplasma: Passed During Intercourse
Mycoplasma genitalium is a different species that infects the genital and urinary tract. You get it through vaginal or anal sex without a condom with someone who carries the infection. Researchers are still working to determine whether it can also spread through oral sex, but that route hasn’t been confirmed yet.
Like the respiratory type, genitalium can be passed along by people who have no signs or symptoms. Many carriers don’t know they’re infected because the bacteria can live in the genital tract without causing obvious problems. When symptoms do appear, they can include burning during urination, unusual discharge, or pelvic pain, but the absence of symptoms doesn’t mean the infection isn’t there or that it can’t be transmitted.
Why Mycoplasma Is Hard to Eliminate
Mycoplasma bacteria are the smallest self-replicating organisms known. They lack a cell wall, which makes them fundamentally different from most other bacteria. This matters for two reasons. First, antibiotics that work by attacking bacterial cell walls (like penicillin and amoxicillin) have no effect on mycoplasma. Second, research from the American Society for Microbiology shows that mycoplasma organisms can slip inside human cells and survive there for extended periods. Once hidden inside your own cells, the bacteria are partially shielded from both your immune system and antibiotics, which helps explain why mycoplasma infections can linger and be difficult to fully clear.
This intracellular survival trick is especially relevant for genitalium infections of the genital tract. The bacteria can persist inside cells even during antibiotic treatment, which is one reason reinfection and treatment failure rates tend to be higher than with other sexually transmitted infections.
How Mycoplasma Is Diagnosed
If your doctor suspects mycoplasma, the preferred testing method is a molecular test called a nucleic acid amplification test, or NAAT. These tests look for the bacteria’s genetic material and offer high accuracy with fast turnaround times. Older methods like blood antibody testing are less reliable because they lack specificity and often require two separate blood draws weeks apart to compare results. Culturing mycoplasma in a lab is possible but extremely slow and only done by specialized reference laboratories, so it’s not practical for guiding treatment decisions.
For respiratory mycoplasma, the test is typically done with a throat or nasal swab. For genitalium, a urine sample or genital swab is used. If you’re experiencing symptoms consistent with either type of mycoplasma infection, asking specifically for NAAT testing gives you the most reliable answer.
Reducing Your Risk
For respiratory mycoplasma, the same habits that reduce spread of other airborne infections apply. Covering coughs and sneezes, washing your hands frequently, and avoiding close contact with people who have respiratory symptoms all lower your chances of picking up the bacteria. In outbreak settings like dorms or nursing homes, good ventilation and keeping sick individuals away from shared spaces help limit spread.
For genitalium, consistent condom use during vaginal and anal sex is the primary way to reduce transmission. Because carriers often have no symptoms, you can’t rely on a partner looking or feeling healthy as a sign they’re infection-free. If you or a partner are diagnosed, both people need to be tested and treated to prevent passing the bacteria back and forth.