Aspiration pneumonia is pneumonia resulting from inhalation of gastric or oropharyngeal fluid containing bacteria.

• A. Pneumonia caused by inhalation of viruses
• B. Pneumonia resulting from inhalation of pollen
• C. Pneumonia resulting from inhalation of gastric or oropharyngeal fluid containing bacteria
• D. Pneumonia caused by exposure to environmental toxins

Answer: (C)

Aspiration pneumonia occurs when material from the mouth or stomach is inhaled into the lungs, bringing bacteria with it and causing infection. The description of pneumonia resulting from inhalation of gastric or oropharyngeal fluid containing bacteria fits this mechanism exactly, since the infectious agent comes from the aspirated content.

In contrast, inhaling viruses can cause viral pneumonia, inhaling pollen tends to trigger allergic or inflammatory responses rather than infection, and inhaling environmental toxins leads to chemical pneumonitis or inhalation injury rather than bacterial infection from aspirated material.