Mycoplasma pneumonia

Mycoplasma pneumonia is a bacterial infection caused by *Mycoplasma pneumoniae*, a member of the class Mollicutes, distinguished by its lack of a cell wall and dependence on host-derived nutrients for replication. The organism primarily colonizes the epithelial surfaces of the upper and lower respiratory tract, where it attaches via specialized adhesion proteins and induces local inflammation through direct cytotoxicity and immune-mediated mechanisms. Clinically, it manifests as primary atypical pneumonia—characterized by insidious onset, minimal sputum production, and frequent extrapulmonary involvement—alongside tracheobronchitis and upper respiratory illness. Its pathogenesis is further complicated by associations with chronic inflammatory conditions, including rheumatological and dermatological syndromes.

The clinical spectrum ranges from asymptomatic infection (noted in ~15% of cases, particularly among adults) to severe primary atypical pneumonia. Most symptomatic cases develop over several days and feature cough, fever, headache, myalgia, sore throat, rhinitis, and wheezing; tracheobronchitis is the most common presentation, especially in pediatric populations. Up to 18% of infected children may require hospitalization, often due to progressive respiratory compromise. Non-pulmonary manifestations occur in up to 25% of cases and include autoimmune hemolytic anemia, central nervous system involvement (e.g., encephalitis), Stevens–Johnson syndrome, and cutaneous eruptions. Rarely, fatal outcomes have been reported secondary to pulmonary edema, bronchiolitis obliterans, or epithelial ulceration. Symptom severity and duration may be attenuated with early antibiotic intervention.

Mycoplasma pneumoniae is globally distributed and causes seasonal outbreaks, particularly in closed or semi-closed settings such as schools and military barracks. It is a leading cause of community-acquired pneumonia in children and young adults, though it accounts for only a minority of adult pneumonias. The disease exhibits a bimodal age distribution, with peak incidence in school-aged children and young adults, and a notable proportion of infections remain subclinical or asymptomatic. Surveillance data indicate that it contributes significantly to outpatient respiratory illness burden but is underdiagnosed due to challenges in laboratory confirmation and clinical mimicry of other etiologies. No specific ICD-10/ICD-11 codes are provided in the source material.

Transmission occurs primarily through respiratory droplets and aerosols generated during coughing or sneezing, with close person-to-person contact facilitating spread. The organism does not survive long outside the human host, and no animal reservoirs or environmental persistence have been documented in the available sources. The incubation period is typically 1–3 weeks, consistent with the delayed onset of symptoms observed clinically.

Children aged 5–15 years are at highest risk for symptomatic infection and hospitalization, likely due to immature immune responses and higher exposure in group settings. Young adults, particularly those in military or institutional environments, also experience elevated incidence. Adults may be more likely to present asymptomatically or with milder disease. Individuals with preexisting autoimmune or immunocompromised conditions may be at increased risk for severe or atypical presentations, including non-pulmonary complications. No specific comorbidities or occupational exposures are explicitly described in the source material.

No vaccine is currently available for *Mycoplasma pneumoniae*. Public health measures focus on standard respiratory hygiene, including handwashing and mask use during outbreaks, particularly in high-density environments. Given the absence of effective prophylaxis, case isolation and contact tracing are recommended in institutional outbreak settings, although evidence for their efficacy in routine community transmission is limited. Antibiotic use for prevention is not supported by current evidence and is discouraged due to risks of resistance and adverse effects.

Surveillance for Mycoplasma pneumonia should prioritize differential diagnosis in patients presenting with prolonged cough, low-grade fever, and non-productive sputum, especially in school-age and young adult populations. Due to clinical overlap with viral and other bacterial pneumonias, laboratory confirmation—such as PCR or serology—is essential for accurate case identification. In sentinel surveillance systems, this entity may be captured under broad categories like 'atypical pneumonia' or 'community-acquired pneumonia without identified pathogen', necessitating targeted testing to avoid misclassification. Source-backed detail on temporal trends, geographic variation, or specific risk factors beyond age and setting is not available in the provided snippets.

1. 1 Wikidata. Mycoplasma pneumoniae.
2. 2 Wikipedia. Mycoplasma pneumonia - Wikipedia.

ICD-10

ICD-11

Total cases

124K

Peak month

2024-11

Coverage

1 reporting countries · 2012-09-15 → 2026-05-02