| Affiliation: | 1. Infection Control Unit, Massachusetts General Hospital, 55 Fruit Street, Bulfinch 334, Boston, MA 02114, USA;2. Division of Infectious Diseases, Massachusetts General Hospital, 55 Fruit Street, Bulfinch 334, Boston, MA, USA;3. Harvard Medical School, Boston, MA, USA;4. Division of Infectious Disease, School of Medicine, University of North Carolina at Chapel Hill, Bioinformatics Building, Suite 2163, Campus Box 7030, 130 Mason Farm Road, Chapel Hill, NC 27599-7030, USA;5. Department of Hospital Epidemiology, UNC Medical Center, Chapel Hill, NC, USA |
