Hematological patients with gram-negative bacteria bloodstream infection: risk factors and outcomes of antibiotic-resistant bacteria

Background Bloodstream infection (BSI) is a life-threatening complication in hematological patients. Multidrug-resistant (MDR) and carbapenem-resistant (CR) Gram-negative bacteria (GNB) BSI have risen sharply, posing major therapeutic challenges. We analyzed pathogen distribution, resistance profiles, CR risk factors, and 30-day mortality predictors in hematological patients with GNB BSI. Methods This retrospective study enrolled hematological patients with confirmed GNB BSI at our institution (May 2023–May 2025). Pathogen distribution and resistance profiles were analyzed. The least absolute shrinkage and selection operator (LASSO) regression analysis and multivariable logistic regression identified nomogram predictors, and model performance was evaluated. Survival was assessed via Kaplan-Meier analysis. Results 210 GNB BSI patients were included (overall 30-day mortality: 19.05%). CR-GNB BSI was associated with significantly higher mortality ( P < 0.001). Carbapenems exposure within 30 days before BSI, length of stay before BSI, inappropriate antimicrobial therapy and IL-6 levels were identified as independent risk factors for CR-GNB BSI. Agranulocytosis time ≥7days, Albumin<30g/L, IL-6 levels and septic shock were independent predictors of 30-day mortality, with IL-6 levels elevated in both CR-GNB patients and non-survivors. IL-6 showed excellent predictive performance for 30-day mortality (AUC = 0.826, cutoff: 3241 pg/mL). Conclusion Antimicrobial-resistant GNB BSI is highly prevalent in hematological patients, with CR-GNB BSI conferring significantly higher mortality. Two internally calibrated nomograms predict 30-day mortality and incident CR-GNB BSI risk. Circulating IL-6 was elevated in CR-GNB patients and non-survivors, which was associated with disease severity and poor 30-day prognosis in hematological patients with GNB BSI, particularly among those with CR-GNB BSI.