Pneumocystis carinii is a fungus because
Fugus - possess rigid cell wall containing chitin mannan and other polysaccharides. The cytoplasmic membrane containing sterols. Cytoplasm contains true nuclei with nuclear membrane, mitochondria and endoplasmic reticulum. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition
mycology
rRNA, mitochondrial protein gene sequence and presence of thymidylate synthase
Cell wall contains glucans
Angifungals are effective against P. Carini
Commonest infection in AIDS
rRNA, mitochondrial protein gene sequence and presence of thymidylate synthase