What Is It?
Pneumonia is an infection of the lungs. Almost all cases of pneumonia are caused by viral or bacterial infections.
When pneumonia is first diagnosed, there often is no way to be sure if the infection is caused by a virus or bacteria. Therefore your doctor will need to treat it with antibiotics.
There are multiple antibiotics that treat pneumonia. The initial choice of drug(s) is made based on the category of pneumonia you most likely have. The two major categories are community acquired pneumonia (CAP) and health care associated pneumonia (HCAP).