What is pneumonia, and how do you avoid the particular germs that cause pneumonia?

Lung infection: Pneumonia is an infection of the lung tissue. There is really no good way to avoid contact with the most common bacteria that cause pneumonia as they colonize ( that is grow on) the nasopharynx ( nasal passages leading to the back of the throat). Infection occurs when the bacterial are "aspirated" into the lung). Risk of infection is lowered with usual good health practices, like not smoking, flu.