1. Department of Internal Medicine, Saint Louis University, St Louis, Missouri, USA
2. Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
3. Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
4. Division of Infectious Diseases, Vanderbilt University, Nashville, Tennessee, USA
5. Duke University School of Medicine, Durham, North Carolina, USA
6. Baylor College of Medicine, Houston, Texas, USA
7. Kaiser Permanente Washington Health Research Institute, Seattle, Washington, USA
8. Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
9. The Emmes Corporation, Rockville, Maryland, USA