1. Department of Hospital Epidemiology and Infection Control, Johns Hopkins Hospital
2. Johns Hopkins Armstrong Institute for Patient Safety and Quality
3. Department of Anesthesia and Critical Care Medicine, Johns Hopkins University School of Medicine
4. Department of Applied Biological Sciences, Johns Hopkins Applied Physics Laboratory
5. Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health
6. Department of Medicine, Johns Hopkins University School of Medicine
7. Johns Hopkins Bloomberg School of Public Health, Department of Epidemiology, Baltimore, Maryland