How Mycoplasma Infections Occur: Transmission Routes and Risk Factors

Mycoplasma is a unique group of microorganisms that fall between viruses and bacteria in terms of biological complexity. As the smallest free-living prokaryotic cells, they lack a cell wall, which makes them naturally resistant to many common antibiotics like penicillin. Among the various types, several species are known to cause human infections, including Mycoplasma pneumoniae, Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma urealyticum. These pathogens are responsible for a range of clinical conditions affecting the respiratory and urogenital systems.

Respiratory Infections Caused by Mycoplasma Pneumoniae

Mycoplasma pneumoniae is one of the most well-known species and a leading cause of atypical pneumonia, especially in school-aged children and young adults. It spreads primarily through the respiratory tract and can lead to infections such as pharyngitis, bronchitis, tracheobronchitis, and pneumonia—often referred to as "walking pneumonia" due to its relatively mild symptoms compared to bacterial pneumonia.

Transmission Through Airborne Droplets

The main source of infection includes individuals who are actively ill or asymptomatic carriers. When infected people cough, sneeze, or talk, they release tiny droplets containing the pathogen into the air. Inhalation of these contaminated respiratory droplets by nearby individuals is the most common transmission route. Because the incubation period can last from 1 to 4 weeks, infected individuals may unknowingly spread the bacteria before showing any symptoms.

Indirect Contact and Surface Contamination

In addition to airborne transmission, indirect contact plays a significant role in spreading M. pneumoniae. The organism can survive on surfaces for several hours. Touching objects or materials contaminated with an infected person's nasal or oral secretions—such as towels, clothing, utensils, or shared electronics—and then touching the mouth, nose, or eyes can lead to infection. This highlights the importance of good hand hygiene and regular disinfection of commonly used items, particularly in schools, households, and healthcare settings.

Genitourinary Tract Infections Linked to Mycoplasma Species

Other clinically relevant mycoplasmas—Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma urealyticum—primarily affect the urogenital tract. Unlike M. pneumoniae, these species are mainly transmitted through sexual contact and are increasingly recognized as causes of non-gonococcal urethritis in men and inflammatory conditions in women, such as bacterial vaginosis, cervicitis, and pelvic inflammatory disease (PID).

Sexual Transmission and Long-Term Complications

M. genitalium, in particular, has been associated with persistent urethral discomfort and is considered a potential contributor to infertility in both men and women. Due to rising antibiotic resistance, especially to macrolides and fluoroquinolones, treating these infections can be challenging. Untreated or recurrent infections may lead to complications such as epididymitis in men and tubal factor infertility in women.

Risk During Pregnancy and Newborn Infection

Pregnant women carrying urogenital mycoplasmas face additional risks. These organisms can ascend into the amniotic cavity, potentially causing chorioamnionitis, preterm labor, or miscarriage. During childbirth, newborns passing through the birth canal can become infected, leading to serious postnatal conditions such as neonatal pneumonia, sepsis, or even meningitis. Early screening and appropriate management during pregnancy may help reduce these adverse outcomes.

Prevention remains key in controlling mycoplasma infections. Practicing respiratory etiquette (like covering coughs and wearing masks when sick), maintaining personal hygiene, avoiding sharing personal items, and using protection during sexual activity are effective strategies. Increased awareness and timely diagnosis—often requiring specialized PCR testing—are essential for proper treatment and reducing transmission in communities.