• Pneumocystis refers to a genus of fungi which can cause pulmonary infection in a variety of mammals. Infection in humans appears to be due to the species Pneumocystis jiroveci (Previously known as Pneumocystis carinii). Until recently, pneuocystis was thought to be a protozoa; however, molecular techniques have now identified this organism as a fungus.
  • Pneumocystis is widely distributed throughout the world and most individuals have been exposed to the organism likely through a respiratory route.
Clinical Consequences
  • Pneumocystis causes pneumonia, known as Pneumocystis Pneumonia (PCP), almost exclusively in immunocompromised patients, especially those with AIDS. Disease usually manifests with a dry cough along with dyspnea and fever. Because pneumocystis pneumonia occurs at such a high frequency in immunocompromised patients, prophylactic antimicrobial treatment is recommended once T-cell counts fall below 200/uL.
  • Treatment and prophylaxis of pneumocystis pneumonia is with Bactrim.