1. Department of Bacteriology, National Institute of Infectious Diseases, Tokyo 162-8640
2. Department of Microbiology, National Institute of Public Health, Tokyo 108-8638
3. Department of Microbiology, Okayama Prefectural Institute for Environmental Science and Public Health, Okayama 701-0298
4. Saitama Institute for Public Health, Saitama 338-0842
5. Saga Prefectural Institute of Public Health, Saga 849-0925
6. Department of Microbiology, Gifu University, School of Medicine, Gifu 500-8750, Japan