Bacterial colonization: pathogenesis and clinical significance.

Bacterial colonization of the respiratory tract frequently precedes the onset of serious invasive infection. It is increasingly evident that the risk for colonization is greatest in patients with serious underlying illness. These patients have been shown to have increased bacterial binding to their respiratory mucosa. In addition to the patients' own predisposition to infection, many of our medical interventions may further compromise the respiratory tract host defenses and permit successful bacterial growth. Methods for prevention of bacterial colonization have not been very successful to date. Although methods to decrease the introduction of exogenous bacteria to patients have been developed, problems persist with the patients' endogenous enteric gram-negative bacilli. It is hoped that increased understanding of bacterial-mucosal interactions will lead to new therapeutic strategies to prevent bacterial invasion of the respiratory tract.