1. Division of Infectious Diseases; Harbor-UCLA Medical Center, and Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center; Torrance California
2. Division of Infectious Diseases; UCSD Medical Center; San Diego California
3. UCLA Clinical and Translational Science Institute; Los Angeles California
4. Division of General Internal Medicine and Health Services Research; David Geffen School of Medicine at UCLA; Los Angeles, and the RAND Corporation; Santa Monica California
5. Department of Hospital Epidemiology; Cedars-Sinai Medical Center; Los Angeles California