1. Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
2. Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
3. Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
4. Division of Pulmonary, Allergy and Critical Care Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.