Pneumocystis pneumonia (PCP) is a serious "yeast-like" fungal infection caused by the fungus Pneumocystis jirovecii.20
Still referred to as PCP (for Pneumocystis carinii pneumonia), the fungal cysts are known to be the cause of opportunistic infections. Most people who have PCP are immunosuppressed or immunocompromised:
- Transplant patients
- Rheumatoid arthritis patients
- HIV/AIDS patients
- Others taking medicines such as corticosteroids which weaken the immune system
Lung sputum or bronchial washing (lavage), and lung biopsy are specimens of choice.
Diagnosis is made using:
- microscopic examination,
- molecular testing by polymerase chain reaction (PCR) for specific DNA, or by
- or by a blood test for detection of beta-D-glucan in the cell wall.
This organism was once thought to be a parasite but is now classified as a yeast-like fungus. It will not grow on conventional mycology media.
21. CDC/Melvin. Image #19330. This image depicts a photomicrograph of a Weigert-Gram-stained human lung tissue impression smear, which revealed the presence of numerous Pneumocystis jirovecii, formerly Pneumocystis carinii, fungal cysts. PHIL public domain. Created 1980. Accessed January 13, 2023. https://phil.cdc.gov/Details.aspx?pid=19330
