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

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.

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.

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.

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.