Atypical Pneumonia

woman sneezing, label: Chlamydia pneumoniae Infection

Chlamydia pneumoniae Infection

Couple relaxing in a hot tub, label: Legionnaires' Disease

Legionnaires’ Disease

Girl blowing nose, label: Mycoplasma pneumoniae Infection

Mycoplasma pneumoniae Infection

Parakeet, label: Psittacosis


Pneumonia is an infection of the lungs that can be caused by viruses, bacteria, and fungi. A common cause of bacterial pneumonia is Streptococcus pneumoniae. Other bacteria can cause pneumonia, including Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci, and Legionella pneumophila. These bacteria are referred to as “atypical” because pneumonia caused by these organisms might have slightly different symptoms, appear different on a chest X-ray, or respond to different antibiotics than the typical bacteria that cause pneumonia. Even though these infections are called “atypical,” they are not uncommon.


Common Types of Pneumonia Caused by Atypical Bacteria
  • Chlamydia pneumoniae Infection
    This illness, caused by Chlamydia pneumoniae, is most common in school-aged children and usually develops into mild pneumonia or bronchitis…
  • Legionnaires’ Disease
    Legionnaires’ disease is a severe type of pneumonia that is caused by a type of bacteria called Legionella
  • Mycoplasma pneumoniae Infection
    This generally mild illness is a common cause of “walking pneumonia”…
  • Psittacosis
    People get this sometimes serious illness, caused by Chlamydia psittaci, from infected pet birds (parrots, parakeets) and poultry (turkeys, ducks)…

How Do You Say That?

Find pronunciation guides below for common words associated with atypical pneumonia.

  • Bronchitis — brahn-KITE-uss
  • Chlamydia — klah-MID-e-a
  • Legionella — lee-juh-NELL-a
  • Legionnaires — lee-juh-NAIRS
  • Mycoplasma — MY-ko-plaz-ma
  • Pneumonia — noo-MOAN-yah
  • Pneumoniae — noo-MOAN-e-a
  • Psittaci — SIT-ah-see
  • Psittacosis — sit-ah-KOH-sis
  • Pneumophila — noo-MAH-fil-ah
  • Streptococcus — strep-toe-KAH-kuss
  • Tracheobronchitis — TRAY-key-o-brahn-KITE-uss

Page last reviewed: July 14, 2016