1. Laboratory of Microbiology and Immunology; Faculty of Pharmaceutical Sciences; Chiba Institute of Science; 3 Shiomi-cho Choshi Chiba 288-0025 Japan
2. Department of Microbiology; School of Medicine; University of Occupational and Environmental Health; Kita-Kyushu 807-8555 Japan
3. Department of Bacteriology; Graduate School of Medical Sciences; Kyushu University; Higashi-ku Fukuoka 819-0395 Japan
4. Department of Medical Microbiology; College of Public Health; University of the Philippines-Manila; Manila Philippines
5. University of Shizuoka; Surugaku-ku Shizuoka 422-8525 Japan