1. Division of Cariology, Operative Dentistry and Endodontics, Faculty of Dentistry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
2. Division of Gastroenterology and Hepatology, Faculty of Dentistry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan
3. Division of Genome-Wide Infectious Diseases, Research Center for GLOBAL and LOCAL Infectious Disease, Oita University, Oita 870-1192, Japan