1. Division of Infectious Diseases, Boston, Massachusetts
2. Infection Control Unit, Massachusetts General Hospital, Boston, Massachusetts
3. Department of Medicine, Harvard Medical School, Boston, Massachusetts
4. Microbiology Laboratory, Pathology Service, Massachusetts General Hospital, Boston, Massachusetts
5. Pediatric Infectious Disease Unit, MassGeneral Hospital for Children, Boston, Massachusetts
6. Department of Pathology, Harvard Medical School, Boston, Massachusetts
7. Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
8. Bureau of Infectious Disease and Laboratory Sciences, Boston, Massachusetts
9. Bureau of Health Care Safety and Quality, Massachusetts Department of Public Health, Boston, Massachusetts