1. Department of Infectious Disease, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
2. Clinical Research Center, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
3. Digestive Disease Key Laboratory of Qingdao, Qingdao, China
4. Department of Gastroenterology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China