1. 1Department of Microbiology, Kanagawa Prefectural Institute of Public Health, 1-3-1 Simomachiya, Chigasaki 253-0087, Japan
2. 2Yamanashi Institute for Public Health, 1-7-31 Fujimi Kofu-shi Yamanashi Prefecture 400-0027, Japan
3. 3Saitama Institute of Public Health, Saitama 338-0824, Japan
4. 4Gunma Prefectural Institute of Public Health and Environmental Sciences, 378 Kamioki, Maebashi, Gunma 371-0052, Japan
5. 5Department of Microbiology, Tokyo Metropolitan Research Laboratory of Public Health, Hyakunincho 3 Chome 24-1, Shinjuku-ku, Tokyo 169-0073, Japan
6. 6Division of Microbiology, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan