PCP is the most common opportunistic infection in persons infected
with HIV. The organism has characteristics of both fungi and
protozoa and causes disease only in immunocompromised hosts.
Patients may present with shortness of breath and a non-productive
cough. Hypoxemia is common and chest x-ray often reveals a mixed
interstitial and alveolar pattern. Treatment is with sulfa-trimethoprim or pentamidine.