1. Center for Infectious Disease, National Medical Center, Seoul, Korea.
2. Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, Korea.
3. Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, St. Vincent's Hospital, The Catholic University of Korea, Seoul, Korea.
4. Department of Internal Medicine, Gil Hospital, Gacheon University, Incheon, Korea.
5. Department of Internal Medicine, Ajou University Hospital, Suwon, Korea.
6. Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Seoul, Korea.
7. Department of Internal Medicine, Daegu Fatima Hospital, Daegu, Korea.
8. Department of Internal Medicine, Dong-A University Hospital, Busan, Korea.
9. Department of Internal Medicine, Korea University Guro Hospital, Seoul, Korea.
10. Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Korea.
11. Department of Internal Medicine, Gyemyeong University Hospital, Daegu, Korea.
12. Department of Internal Medicine, Inha University Hospital, Incheon, Korea.