Infection control and pneumonia prophylaxis strategies in the intensive care unit.

Conventional infection control approaches, such as dedicated surveillance and control programs and barrier isolation techniques, effectively interrupt acquisition of many pathogens and reduce infection rates in the intensive care unit (ICU). However, a substantial proportion of infections results from endogenous rather than acquired organisms and require that we also develop strategies to prevent the progression from colonization to infection. Studies of systemic antimicrobial prophylaxis for patients at risk for pneumonia have consistently failed to demonstrate benefit. Topical endotracheal prophylaxis succeeded in preventing pneumonia but was complicated by the emergence of intrinsically resistant gram-negative bacilli. More recently, a number of trails have evaluated selective decontamination of the oropharynx and gastrointestinal tract with nonabsorbable antibiotics. These regimens have demonstrated a substantial impact on pneumonia and overall infection rates in ICU patients. Further investigation will define the role of selective decontamination in selected patient populations as well as address concerns over selection of resistance. Other strategies, including immunoprophylaxis, colonization-resistant devices, and methods to decrease bacterial adherence may also prevent progression from colonization to infection and will be the subject of future investigation.