1. Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, College of Medicine, Chang Gung University, Taoyuan 33375, Taiwan
2. Infection Control Committee, Chang Gung Memorial Hospital at Linkou, Taoyuan 33375, Taiwan
3. Division of Infectious Diseases, Department of Internal Medicine, New Taipei Municipal TuCheng Hospital (Built and Operated by Chang Gung), New Taipei City 23652, Taiwan