Pneumonia is the second most common nosocomial infection and is associated with substantial morbidity and mortality. 

Most patients who have nosocomial pneumonia are infants, young children, and persons >65 years of age. (1)

 

Nosocomial pneumonia consists of an hospital-acquired infection of the pulmonary parenchyma occurring in patients who were admitted to the hospital for more than 48 hours. Nosocomial pneumonia can be classified into Hospital-Acquired Pneumonia (HAP), Ventilator-Acquired Pneumonia (VAP), and Health Care Associated Pneumonia (HCAP).*

 

Bacteria can invade the lower respiratory tract by aspiration of oropharyngeal organisms, inhalation of aerosols containing bacteria, or, less frequently, by hematogenous spread from a distant body site. In addition, bacterial translocation from the gastrointestinal tract has been hypothesized recently as a mechanism for infection. (1)

 

Currently, therapy often involves monotherapy or combination therapy with antimicrobial agents against Gram negative and positive bacteria.*