The Impact of Bacterial Infections on Delayed Hematopoietic Recovery in Patients with Acute Leukemia After Induction and Consolidation Therapy

Objective: To evaluate whether documented bacterial infection or neutropenic fever is associated with delayed hematopoietic recovery in patients with acute leukemia undergoing induction or consolidation chemotherapy. Methods: We conducted a retrospective observational study of 171 adult patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) treated between 2022 and 2025. Patients were divided into three groups: (1) microbiologically documented infection (n = 73); (2) neutropenic fever without pathogen identification (n = 73); and (3) no fever or infection (n = 25). Hematopoietic recovery was assessed by time to neutrophil recovery (>0.5 × 109/L) and time to reticulocyte production index (RPI) > 1.0. Statistical comparisons were performed using ANOVA or Kruskal–Wallis tests as appropriate. Results: The mean time to neutrophil recovery was 32.0 days (95% CI: 30.0–34.0) in Group 1, 28.4 days (95% CI: 27.3–29.6) in Group 2, and 15.2 days (95% CI: 14.3–16.2) in Group 3 (p = 0.0039). The mean time to RPI > 1.0 was 36.3 days (95% CI: 34.2–38.4), 33.0 days (95% CI: 31.8–34.2), and 19.4 days (95% CI: 18.5–20.3), respectively (p = 0.0018). Differences between Groups 1 and 2 were not statistically significant. Conclusions: Infection and neutropenic fever are associated with significantly prolonged hematopoietic recovery following chemotherapy for acute leukemia. Delayed regeneration may increase the risk of complications and negatively affect treatment outcomes.