Clinical and Epidemiologic Features of Mycoplasma pneumoniae Infection Among Adults Hospitalized with Community-acquired Pneumonia

Background/Purpose: The burden and epidemiology of Mycoplasma pneumoniae (Mp) community-acquired pneumonia (CAP) among hospitalized U. S. adults (>= 18 years) are poorly understood. Methods: In the Etiology of Pneumonia in the Community (EPIC) study, we prospectively enrolled 2272 adults hospitalized with radiographically-confirmed pneumonia between January 2010-June 2012 and tested nasopharyngeal/oropharyngeal swabs for Mp by real-time polymerase chain reaction (PCR). Clinical and epidemiological features of Mp-PCR-positive and -negative adults were compared using logistic regression. Macrolide susceptibility was assessed by genotyping isolates. Results: Among 2272 adults, 43 (1.8%) were Mp-PCR-positive (median age: 45 years); 52% were male, and 56% were non-Hispanic white. Only one patient had Mp macrolide resistance. Four (9%) were admitted to the intensive care unit (ICU). No in-hospital deaths were reported. Of the 9 (21%) who received an outpatient antibiotic <= 5 days pre-admission, 2 (22%) received an antibiotic with Mp activity. Variables significantly associated with higher odds of Mp detection included age {18-29 years [(adjusted odds ratio (aOR): 11.7 (95% confidence interval (CI): 5.1- 26.6) versus >= 50 years]} and radiographic lymphadenopathy [aOR: 3.5 (95% CI: 1.2- 9.3)]. Conclusions: M. pneumoniae, commonly known to cause "walking pneumonia", was detected among hospitalized adults, with the highest prevalence among young adults. Although associated with clinically non-specific symptoms, approximately one out of every ten patients were admitted to the ICU. Increasing access to M. pneumoniae point-of-care testing could facilitate targeted treatment and avoid hospitalization.