1. Department of Microbiology, College of Medicine, Konyang University, Daejeon 35365, Korea.
2. Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Konyang University, Daejeon 35365, Korea.
3. Priority Research Center, Myunggok Medical Research Institute, College of Medicine, Konyang University, Daejeon 35365, Korea.