1. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Chonbuk National University Hospital, Jeonju, Korea.
4. Department of Preventive Medicine, Chonbuk National University Hospital, Jeonju, Korea.
5. Department of Microbiology, Chonbuk National University Hospital, Jeonju, Korea.
6. Research Institute of Clinical Medicine of Chonbuk National University-Chonbuk National University Hospital, Jeonju, Korea.