Bloodstream Infections in Patients with Malignancy: Microbiological Epidemiology, Antimicrobial Resistance, and Factors Associated with Mortality in a Nine-Year Single-Center Retrospective Cohort

Background/Objectives: Bloodstream infections (BSIs) are a major cause of morbidity and mortality among patients with malignancy because of disease-related immune dysfunction, intensive chemotherapy, neutropenia, and frequent exposure to invasive procedures. This study aimed to characterize the microbiological profile and antimicrobial resistance patterns of BSIs in patients with malignancy and to identify clinical and laboratory factors associated with in-hospital mortality, explicitly treating ICU admission as an associated marker of critical illness rather than a predictor.

Methods

This retrospective study included 191 clinically significant BSI episodes recorded between 2016 and 2025; record review confirmed that each included episode represented a different patient. Demographic characteristics, underlying diagnoses, comorbidities, chemotherapy history, catheter status, infection source, hematological and biochemical parameters, bloodstream pathogen category, antimicrobial susceptibility patterns, ward and intensive care unit (ICU) lengths of stay, and in-hospital mortality were evaluated. Categorical variables were compared using the chi-square or Fisher’s exact test, while continuous variables were analyzed using the Mann–Whitney U test. Multivariable logistic regression analysis was performed to identify factors independently associated with in-hospital mortality.