Affiliation: | a Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, 301-721, Republic of Korea;b College of Medicine, Chungnam National University, Daejeon 35015, Republic of Korea;c Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon 35015, Republic of Korea. |