The causes of pneumonia. Md. Saifur Rahman Pneumonia may be caused by viral infections, bacterial infections, or fungi; less frequently by other causes. The most common bacterial type that causes pneumonia is streptococcus pneumoniae. You may likeDo I need car insurance?What is car insurance?How could I get cheaper car insurance?What is auto insurance?Why Adulterant food is the barrier to sound health?What are the producers?What are food preservatives?What is food chain?What is tertiary consumer?