Synergistic Effect of Antimicrobial Resistance and Cytogenetic Risk on Mortality in Acute Myeloid Leukemia.

Background/aim: Acute myeloid leukemia (AML) is an aggressive hematological malignancy requiring intensive chemotherapy, which induces profound immunosuppression. Multidrug-resistant Gram-negative (MDRGN) bacterial colonization and infection are an emerging challenge in AML management, potentially worsening survival outcomes. This retrospective single-center cohort study evaluated the impact of MDRGN colonization and infection on overall survival (OS) in patients with AML undergoing chemotherapy.

Materials and methods: MDRGN status was determined via routine cultures, while infection was defined by positive sterile-site cultures accompanied by clinical symptoms. Cytogenetic risk was stratified according to ELN 2022 criteria. Survival analysis was performed using the Kaplan-Meier method.

Results: A total of 64 patients with AML were analyzed, with a median OS of 8.03 months. MDRGN-colonized patients had significantly shorter OS (3.53 months) than non-colonized patients (18.83 months; p=0.024). High-risk cytogenetics independently reduced OS (4.63 vs. 18.93 months; p=0.011). Patients with both high-risk cytogenetics and MDRGN colonization had the poorest prognosis, with a median OS of 1.47 months. MDRGN colonization was associated with significantly increased infection risk, treatment-related complications, and reduced survival in AML. The combined effect of antimicrobial resistance and high-risk cytogenetics suggests a synergistic impact on prognosis. Delayed targeted antibiotic therapy, chemotherapy modifications, and increased septic episodes likely contributed to the observed mortality.

Conclusion: MDRGN colonization is a critical negative prognostic factor in AML, particularly in patients with adverse cytogenetics. Strengthening infection control measures, implementing rapid molecular diagnostics, and optimizing antimicrobial stewardship are essential to improve outcomes.