1. Division of Infection Control, Dokkyo Medical University Saitama Medical Center, Japan
2. Department of Infection Control and Prevention, The University of Tokyo Hospital, Japan
3. Department of Microbiology, Fujita Health University School of Medicine, Japan
4. Department of Neurology, Dokkyo Medical University Saitama Medical Center, Japan
5. Department of Otorhinolaryngology, Dokkyo Medical University Saitama Medical Center, Japan