Nosocomial pneumonia in patients in intensive care units.

Nosocomial pneumonia is a major cause of mortality among patients in intensive care units, despite recent advances in antimicrobial therapy. Aerobic Gram-negative bacilli remain the pathogens responsible for most of these pneumonias. These organisms colonize the oropharynx of severely ill patients, and their subsequent aspiration results in lower respiratory tract infection. Recent investigation into the pathogenesis of oropharyngeal bacterial colonization has shown the central importance of bacterial adherence mechanisms.