More than 3 million cases of pneumonia occur annually in the United States. Defined as an infection of the lung, pneumonia can be bacterial, viral, of fungal in origin. The infection is usually further categorized into community-acquired pneumonia or hospital- or healthcare-acquired pneumonia. Pneumonia accounts for approximately 15% of all hospital-associated infections with estimated mortality rates of 20% to 33%. The primary risk factor for the development of hospital-associated bacterial pneumonia is mechanical ventilation. This condition is known as ventilator-acquired pneumonia.