Pneumonia is an infectious disease that clinically refers to inflammation of the terminal airways, alveoli, and interstitial spaces of the lungs, mainly due to pathogenic microorganisms, immune damage, and allergic medications. The pathogens that commonly cause pneumonia are as follows: 1. bacterial pneumonia, including Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus aureus, Klebsiella pneumoniae, Mycobacterium influenzae, Pseudomonas aeruginosa, Escherichia coli, etc. 2. viruses, including measles virus, influenza virus, cytomegalovirus, adenovirus, etc. 3. Mycoplasma pneumoniae, Chlamydia, Rickettsia, etc. 4. fungal infection.