1. Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan
2. Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, Tampa, FL 33612, USA
3. Laboratory of Molecular Microbiology, Department of Basic Laboratory Sciences, Osaka University Graduate School of Medicine, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan