1. Lead Generation Research Laboratory; Tanabe Seiyaku Co., Ltd.; Toda Saitama 335-8505 Japan
2. Pharmaceutical Development Research Laboratory; Tanabe Seiyaku Co., Ltd.; Toda Saitama 335-8505 Japan
3. Department of Microbiology; Hiroshima University School of Dentistry; Hiroshima Hiroshima 734-8553 Japan