1. Harvard Pilgrim Health Care Institute, Department of Population Medicine, Harvard Medical School, Boston, Massachusetts
2. Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
3. Department of Pharmacy Administration and Clinical Pharmacy, Xi’an Jiaotong University School of Pharmacy, Xi’an, Shaanxi, China
4. Department of Medicine, Brigham and Women’s Faulkner Hospital, Boston, Massachusetts
5. Infection Control Unit, Massachusetts General Hospital, Boston, Massachusetts