About Pneumocystis pneumonia the true statement is:
Pneumocystis jirovecii is a fungus responding to Cotrimoxazole. It causes opportunistic pneumonia in patients with HIV infection. 
The most common radiology finding is a normal X-ray chest.  However, the most typical X-ray is  a bat wing distribution of infiltrates with pneumocysts in peripheral fields. 
Steroids are combined with Cotrimoxazole in treatment of severe Pneumocystis jirovecii pneumonia.