1. Department of Pediatrics; Asahikawa Kosei Hospital; Asahikawa Hokkaido Japan
2. Department of Pediatrics; Subaru Health Insurance Society Ota Memorial Hospital; Ota Gunma Japan
3. Department of Pediatrics; Sekishinkai Sayama Hospital; Sayama Saitama Japan
4. Kitasato Institute; Kitasato University Research Center for Anti-infectious Drugs; Tokyo Japan