Because P. aeruginosa is found in most moist environments (e.g., in soil, in tap water, and on countertops), people routinely come into contact with the organism. The many factors that predispose to P. aeruginosa infection include disruption of cutaneous or mucosal barriers (e.g., due to burns or trauma), immunosuppression (e.g., due to neutropenia, AIDS, or diabetes), and disruption of the normal bacterial flora (e.g., due to broad-spectrum antibiotic therapy).

• P. aeruginosa is no longer a major cause of life-threatening bacteremia among pts with neutropenia or burn injury.
• P. aeruginosa bacteremia is currently most common among pts in the ICU.