

History & Disease Patterns


Mycoplasma pneumoniae (M. pneumoniae) was discovered in 1944 in a patient with “atypical” pneumonia. It was first thought to be a virus or fungus, which is why the name “mycoplasma” (Greek for “fungus-formed”) was chosen. It was eventually learned to be a bacterium, but unlike many other bacteria, it has many unique characteristics. For example, it does not have a rigid cell wall, which affects the types of antibiotics that work well against it. This is why it is classified as an “atypical” bacterium. It is also the smallest organism capable of living and reproducing on its own. Smaller germs, like viruses, have to live and reproduce inside cells.

Disease Patterns

M. pneumoniae infections are common in the United States. The number of infections varies over time, with peaks of disease every 3 to 7 years. An estimated 2 million cases of M. pneumoniae infections occur each year in the United States.1,2 However, many infections are not diagnosed, so the actual number is likely higher, and the true size of the health problem is unknown. This illness can happen any time during the year but may be more common in summer and early fall.3


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 Winchell JM. Mycoplasma pneumoniae – A national public health perspective. Curr Pediatr Rev. 2013; doi:10.2174/15733963113099990009