Mycoplasma pneumoniae (M. pneumoniae) is an atypical bacterium (the singular form of bacteria) that causes lung infection. It is a common cause of community-acquired pneumonia (lung infections developed outside of a hospital). M. pneumoniae infections are sometimes referred to as walking pneumonia. Some experts estimate that between 1 and 10 out of every 50 cases of community-acquired pneumonia in the United States is caused by M. pneumoniae. However, not everyone who is exposed to M. pneumoniae develops pneumonia. Outbreaks of M. pneumoniae occur mostly in crowded environments, like schools, college dormitories, military barracks, and nursing homes, where transmission is possible through airborne droplets from close person-to-person contact. M. pneumoniae infections also frequently spread within households. Clinical Features & Complications Mycoplasma pneumoniae (M. pneumoniae) infections can occur in the upper or lower respiratory tract. The bacterium can also cause a wide array of extrapulmonary manifestations without obvious respiratory disease. Therefore, patients may have a highly variable presentation. The incubation period is generally between 1 to 4 weeks; however, shorter and longer durations have been documented. Infection most commonly results in: •Tracheobronchitis •Pharyngitis •Malaise •Fever •Cough •Headache Onset can be gradual and subacute, slowly progressing to a higher fever and a persistent cough. While the disease can persist for weeks or months, it is frequently mild and self-resolving. The organism may persist for several weeks in the oropharynx despite completion of recommended antimicrobial therapy and resolution of clinical symptoms. Younger patients often manifest with different clinical characteristics than patients over 5 years old. For example, the infection may run subclinical, mild, and non-pneumonia courses. Infections in younger patients are often characterized by coryza and wheezing without concomitant fever, and sometimes include diarrhea and vomiting. Clinical Complications Severe complications can occur that result in hospitalization and sometimes death. Complications that have been reported include: •Severe pneumonia •Exacerbation of asthma •Encephalitis •Hemolytic anemia •Renal dysfunction •Gastrointestinal complaints •Erythema multiforme, Stevens-Johnson syndrome, or toxic epidermal necrolysis References •Waites KB, Atkinson TP. The role of mycoplasma in upper respiratory infections. Curr Infect Dis Rep. 2009;11:198–206. •Waites KB, Talkington DF. Mycoplasma pneumoniae and its role as a human pathogen. Clin Microbiol Rev. 2004;17:697–728. cdc.gov/pneumonia/atypical/mycoplasma/
Posted on: Sat, 18 Oct 2014 01:49:41 +0000