1. Department of Bacteriology; Graduate School of Medicine, University of the Ryukyus; Nishihara Okinawa 903-0213 Japan
2. Department of Food Science and Nutrition; Nara Women's University; Nara 630-8506 Japan
3. Department of Pathology and Comprehensive Cancer Center; University of Michigan Medical School; 3852 E Medical Center Dr Ann Arbor MI 48109 USA
4. Tropical Biosphere Research Center University of the Ryukyus; Nishihara Okinawa 903-0213 Japan
5. Department of Bacterial Pathogenesis; Infection and Host Response Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Yushima Bunkyo-ku 1130034 Tokyo Japan