Selective decontamination of the digestive tract: risks outweigh benefits for intensive care unit patients.

Selective decontamination of the digestive tract (SDD) involves the administration of non-absorbable antibiotics (+/- a systemic antibiotic) to prevent colonization and infection in intensive care unit patients. The regimen is targeted at nosocomial gram-negative bacilli, some gram-positive bacteria and yeast. Although all studies of SDD have demonstrated reduced rates of bacterial colonization and most yielded lower respiratory tract infection, it is unclear if the major impact of SDD is on pneumonia or tracheobronchitis. SDD regimens utilizing a broad spectrum, systemic antibiotic appear to be more effective, suggesting that this constitutes early treatment rather than prophylaxis. To date, there is conflicting evidence that SDD significantly reduces length of stay, mortality, or hospital costs. Currently, there are concerns that SDD may result in increased colonization and infection with gram-positive organisms and multi-drug resistant pathogens, particularly in medical ICU patients or when used for extended periods of time.