Bacterial colonization of the tracheobronchial tree

Colonization of the tracheobronchial tree, especially with aerobic gram-negative bacteria, is a major and increasing problem in seriously ill and hospitalized patients. The association between colonization and nosocomial pneumonia is well established; pneumonia develops after aspiration of pathogens that have initially colonized the tracheobronchial tree. The same risk factors associated with hospital-acquired pneumonia are relevant for the development of colonization. An understanding of the pathogenesis of bacterial colonization is advancing rapidly and may provide the basis for strategies to diminish this significant problem.