Retrospective Analysis of the Epidemiology and Risk Factors for Recurrent Biliary-Source Bloodstream Infections in Oncologic Patients

Background: We aimed to describe the clinical and microbiological characteristics of biliary-source bloodstream infections (bBSIs) in patients with malignancies and identify risk factors for recurrence. Methods: All bBSI episodes in patients with active solid tumors during 2021–2025 were retrospectively reviewed. Independent risk factors for recurrent bBSI and mortality were identified. A previously published recurrence risk score was externally validated. Results: Overall, 136 patients experienced 199 bBSI episodes. Pancreatic (36.7%) and biliary tract (33.2%) were the most common cancers, and 60.8% had metastatic disease. The main pathogens were Escherichia coli (43.2%), Klebsiella pneumoniae (24.1%), and Enterococcus faecium (19.1%), and multidrug-resistant organisms accounted for 19.1%. Inappropriate empirical antibiotic treatment (IEAT) occurred in 37.2% and was independently associated with increased 30-day mortality, together with metastatic disease and septic shock. Thirty-day mortality was 24.6%. Recurrent bBSI occurred in 35.7% and was independently associated with biliary tract cancer, previous multidrug-resistant isolation, and prior hospitalization for suspected biliary infection. The externally validated recurrence score showed excellent discrimination (AUC 0.815). Conclusions: bBSI in oncology patients is associated with high rates of MDR pathogens, IEAT, recurrence, and mortality. A simple clinical score may identify patients at high risk of recurrence and guide preventive strategies.