1. Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
2. School of Bioscience and Technology, Chengdu Medical College, Chengdu, Sichuan 610500, P.R. China
3. Department of Hepatobiliary Surgery, Sichuan Provincial People's Hospital, Chengdu, Sichuan 610000, P.R. China
4. Department of Hepatobiliary Surgery, Pidu District People's Hospital of Chengdu, Chengdu, Sichuan 611730, P.R. China
5. Department of Nosocomial Infection Control, Pidu District People's Hospital of Chengdu, Chengdu, Sichuan 611730, P.R. China