Pneumocystis jirovecii

  • Pneumocystis jirovecii pneumonia (PCP)

  • Pneumocystis carinii (previous term)

  • O2 desaturation test

  • Clotrimoxazole preventative therapy

Historical aspects

  • Scientists have changed both the classification and the name of this organism since it first appeared in patients with HIV in the 1980s. Pneumocystis jirovecii used to be classified as a protozoan but is now considered a fungus. Pneumocystis jirovecii used to be called Pneumocystis carinii. When scientists renamed P. carinii to P. jirovecii, some people considered using the abbreviation “PJP,” but to avoid confusion, Pneumocystis jirovecii pneumonia is still abbreviated “PCP"