Nosocomial pneumonia: pathogenesis and recent advances in diagnosis and therapy.

Despite recent progress in the prevention and treatment of hospital-acquired infections, nosocomial pneumonia remains an important problem among critically ill patients. Nosocomial pneumonia develops in five to 10 patients per 1,000 admissions and has a mortality rate of 20%-50%. This review focuses on three areas of nosocomial pneumonia that have been the subject of investigation in recent years: (1) pathogenesis, especially the role of gastric colonization with gram-negative bacilli in retrograde pharyngeal spread; (2) diagnosis, particularly by means of bronchoalveolar lavage and the protected specimen brush during bronchoscopy; and (3) therapy with extended-spectrum penicillins, third-generation cephalosporins, imipenem, aztreonam, and quinolones.