1. Department of Bacteriology, School of Medicine, Kanazawa University, Kanazawa 920-8640,1
2. Department of Veterinary Science, College of Agriculture, Osaka Prefecture University, Sakai, Osaka 599-8531,2
3. Department of Bacteriology, Toyama Institute of Health, Toyama 939-0363,3 and
4. Department of Bacteriology, Okayama University Medical School, Okayama 700-8558,4 Japan