1. Hanyang University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
4. Division of Infectious Diseases, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea.
5. Department of Internal Medicine, Inje University Sanggye Paik Hospital, Seoul, Korea.
6. Department of Pediatrics, Chung-Ang University Hospital, Seoul, Korea.
7. Department of Infectious Diseases, Seongnam Citizens Medical Center, Seongnam, Korea.
8. Infection Control Office, Seoul National University Bundang Hospital, Seongnam, Korea.
9. Department of Pediatrics, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.