 Bloodstream infections are a common and serious problem, affecting 15 of critically ill patients, increasing length of hospital stay by 2-3 weeks, adding 25,000-40,000 in excess hospital costs, and tripling the risk of death. At the same time, antibiotic overuse is also a common and serious problem, in that 30-50 of antibiotic use is unnecessary or inappropriate, and results in avoidable drug side effects such as kidney failure, Clostridium difficile infection, increased costs, and spiraling antibiotic resistance rates. The greatest contributor to antibiotic overuse is excessive durations of treatment. 