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Girl sneezing

Mycoplasma pneumoniae  is an "atypical" bacterium (the singular form of bacteria) that  commonly causes infections of the respiratory system. The most common type of illness caused by these bacteria, especially in children, is tracheobronchitis, commonly called a chest cold. This illness is often seen with other upper respiratory tract symptoms, like a sore throat. Sometimes M. pneumoniae infection can cause pneumonia, a more serious infection of the lungs, which may require treatment or care in 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 (lung infections developed outside of a hospital) in the United States is caused by M. pneumoniae. However, not everyone who is exposed to M. pneumoniae develops pneumonia.

In general, M. pneumoniae infection is a mild illness that is most common in young adults and school-aged children.  Outbreaks of M. pneumoniae occur mostly in crowded environments, like schools, college dormitories, military barracks, and nursing homes,  when small droplets of water that contain the bacteria get into the air by coughing and sneezing while in close contact with others, who then breathe in the bacteria. M. pneumoniae infections often spread within households.

Fact Sheet

Mycoplasma Fact Sheet

This fact sheet [1 page] describes what Mycoplasma pneumoniae infection is, its symptoms, how it’s spread and treated, and who is at increased risk.

How Do You Say That?

Find pronunciation guides below for common words associated with Mycoplasma pneumoniae.

  • Bronchitis — brahn-KITE-uss
  • Mycoplasma — MY-ko-plaz-ma
  • Pneumonia — noo-MOAN-yah
  • Pneumoniae — noo-MOAN-e-a
  • Tracheobronchitis — TRAY-key-o-brahn-KITE-uss