1. Division of Infectious Diseases, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Division of Infectious Diseases, Department of Internal Medicine, Kyungpook National University, School of Medicine, Kyungpook National University Chilgok Hospital, Daegu, Korea.
3. Division of Infectious Diseases, Department of Internal Medicine, Kyungpook National University, School of Medicine, Kyungpook National University Hospital, Daegu, Korea.
4. Division of Infectious Diseases, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.
7. Department of Internal Medicine, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, Korea.
8. Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, Jeju National University, Jeju, Korea.
9. Division of Infectious Diseases, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.
10. Division of Infectious Disease, Department of Internal Medicine, National Medical Center, Seoul, Korea.
11. Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, Korea.
12. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
13. Hospital Infection Control Team, Daegu Medical Center, Daegu, Korea.
14. Division of Respiratory Diseases, Department of Internal Medicine, Masan Medical Center, Changwon, Korea.
15. Department of Internal Medicine, Andong Medical Center, Andong, Korea.
16. Department of Internal Medicine, Konyang University Hospital, Daejeon, Korea.