Changing Patterns of Causative Pathogens over Time and Efficacy of Empirical Antibiotic Therapies in Acute Cholangitis with Bacteremia

BACKGROUND/AIMS: To select appropriate empirical antibiotics, updates on the changes in pathogens are essential. We aimed to investigate the changes in pathogens and their antibiotic susceptibility in acute cholangitis (AC) with bacteremia over a period of 15 years. Furthermore, the efficacy of empirical antibiotic therapies and the risk factors predicting antibiotic-resistant pathogens (ARPs) were analyzed. METHODS: A total of 568 patients with AC and bacteremia who were admitted to Daegu Catholic University Medical Center from January 2006 to December 2020 were included. Their medical records were retrospectively reviewed. In addition, the data were grouped and analyzed at 3-year intervals under the criteria of Tokyo Guideline 2018. RESULTS: During the study period, 596 pathogens were isolated from blood cultures of 568 patients. The three most common pathogens were Escherichia coli (50.5%), Klebsiella species (24.5%), and Enterococcus species (8.1%). The proportion of vancomycin-resistant Enterococci (VRE) has increased since the mid-2010 (0.0% to 4.3%, p=0.007). There was emergence of carbapenem-resistant Enterobacteriaceae (CRE) in 2018 to 2020, albeit not statistically significant (1.3%, p=0.096). Risk factors predicting ARP were healthcare-associated infection, history of previous biliary intervention, and the severity of AC. For patients with these aforementioned risk factors, imipenem was the most effective antibiotic and piperacillin-tazobactam was also effective but to a lesser degree (susceptibility rates of 92.1% and 75.0%, respectively). CONCLUSIONS: The proportion of VRE has increased and CRE has emerged in AC. In addition, healthcare-associated infection, history of previous biliary intervention, and the severity of AC were independent risk factors predicting ARP. For patients with these risk factors, the administration of imipenem or piperacillin-tazobactam should be considered.