1. Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama, 700-8558 , Japan
2. Department of Infectious Diseases, Okayama University Hospital , Okayama, 700-8558 , Japan
3. Department of Medical Laboratory Science, Okayama University Graduate School of Health Sciences , Okayama, 700-8558 , Japan
4. Microbiology Division , Clinical Laboratory, , Okayama, 700-8558 , Japan
5. Okayama University Hospital , Clinical Laboratory, , Okayama, 700-8558 , Japan