Retrospective comparative analysis of risk factors and outcomes in patients with carbapenem resistant Acinetobacter baumannii bloodstream infections: cefoperazone–sulbactam associated with resistance and tigecycline increased the mortality Tianshui Niu,1 TingTing Xiao,1 Lihua Guo,1 Wei Yu,2 Yunbo Chen,1 Beiwen Zheng,1 Chen Huang,1 Xiao Yu,1 Yonghong Xiao1 1Collaborative Initiative Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China; 2Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, 310003, China Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a rapidly emerging, life-threatening nosocomial infection. This study aimed to explore the risk factors, clinical features, antimicrobial therapy, and outcomes of CRAB bloodstream infections (BSIs).Methods: This is a retrospective, comparative analysis of data from patients with A. baumannii BSI, treated from 2012 to 2015 at a tertiary teaching hospital. Risk factors associated with CRAB BSI and factors associated with the 28-day mortality were evaluated using logistic analyses.Results: Data from 293 patients with confirmed A. baumannii BSI were included; 242 (82.6%) patients had CRAB BSI and 51 (17.4%) patients had non-CRAB BSI. Risk factors significantly associated with CRAB BSI were a previous intensive care unit (ICU) stay (P