Saturday November 5, 2005
Pneumocystis Jiroveci (PCP) - previously P. carinii

Patients with Pneumocystis jiroveci (PCP) usually detriorate in first 2 -3 days of treatment with worsening of A-a gradient (Alveolar-arterial gradient of oxygen) and this should not be presumed as treatment failure. If patient continue to show same trend by 5-7 days than treatment failure should be considered. Initial worsening is due to inflammation as organisms get killed and this is one of the reason to administer steroid at the initiation of PCP treatment.

Nomenclature has been changed as DNA analysis by PCR (polymerase chain reaction) showed that sequences from P. jiroveci (human-derived) differ by 5% from P. carinii (rat-derived). But acronym PCP has been retained for Pneumocystis pneumonia. Jiroveci (pronounced "yee row vet zee") has been named in honor of the Czech parasitologist Otto Jirovec, who is credited with describing the microbe in humans in 1999.

Refrences: click on link to get article/abstract
1. A New Name (Pneumocystis jiroveci) for Pneumocystis from Humans - cdc.gov
2. Pneumocystis pneumonia in humans is caused by P jiroveci not P carinii - Thorax 2004;59:83-84 (letter to editor)