Acute lung injury and bacterial infection.

The relationships between acute lung injury and bacterial infection are complex. Indeed, sepsis and in particular pneumonia are leading causes of acute lung injury. Bacterial superinfection of the lung is a frequent complication of acute lung injury. Because of impaired host defenses and prolonged mechanical ventilation, more than one third of patients with the acute respiratory distress syndrome acquire ventilator-associated pneumonia, with resistant pathogens in most instances. This complication is responsible for more than a doubling of the time on mechanical ventilation but does not seem to increase mortality.