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Fast Facts

  • Mycoplasma pneumoniae is a small bacterium that can infect the lungs and other parts of the respiratory tract and is spread from person-to-person.
  • Pneumonia caused by M. pneumoniae is considered an atypical bacterial pneumonia because it has different symptoms, can appear different on x-ray, and historically the antibiotics commonly used to treat bacterial pneumonia did not work against it.
  • An M. pneumoniae infection is characterized by a gradual onset of symptoms and long incubation period (1 to 4 weeks).
  • Most cases of M. pneumoniae infection are mild and get better on their own without treatment, but serious complications can occur.
  • An estimated 2 million cases of M. pneumoniae infection occur each year in the United States, but the true size of the health problem is unknown and likely underestimated.1,2
  • M. pneumoniae is the second most common cause of pneumonia-related hospitalization in adults with community-acquired pneumonia (lung infections developed outside of a hospital).2
  • • Between 1 and 10 out of every 50 cases of community-acquired pneumonia in the United States may be caused by M. pneumoniae.1,3,4,5,6


1 Marston BJ, Plouffe JF, File Jr TM, Hackman BA, Salstrom SJ, Lipman HB, Kolczak MS, Breiman RF. Incidence of community-acquired pneumonia requiring hospitalization. Results of a population-based active surveillance study in Ohio. The Community-Based Pneumoniae Incidence Study Group. Arch Intern Med. 1997;157:1709–18.

2 Porath A, Schlaeffer F, Lieberman D. The epidemiology of community-acquired pneumonia among hospitalized adults. J Infect. 1997;34:41–8.

3 Foy HM. Infections caused by Mycoplasma pneumoniae and possible carrier state in different populations of patients. Clin Infect Dis. 1993;17:S37–46.

4 Foy HM, Kenny GE, McMahan R, Mansy AM, Grayston JT. Mycoplasma pneumoniae pneumonia in an urban area. Five years of surveillance. JAMA. 1970;214:1666–72.

5 Mundy LM, Oldach D, Auwaerter PG, et al. Implications for macrolide treatment in community-acquired pneumonia. Hopkins CAP Team. Chest. 1998;113:1201–6.

6 Michelow IC, Olsen K, Lozano J, et al. Epidemiology and clinical characteristics of community-acquired pneumonia in hospitalized children. Pediatrics. 2004;113:701–7.