Pre-engraftment bloodstream infections in acute leukemia patients undergoing unrelated cord blood transplantation following intensified myeloablative conditioning without ATG.

The aim of this study is to investigate the impact of pre-engraftment bloodstream infections (BSIs) on the outcomes in acute leukemia patients undergoing myeloablative cord blood transplantation (CBT). A total of 226 acute leukemia patients who received unrelated CBT were enrolled in this study, and all these patients received an intensified myeloablative conditioning without ATG. Pre-engraftment BSIs occurred in 72 patients (31.9 %), and the median time of onset was 4.5 days after cord blood infusion, BSIs of gram-negative bacilli, and gram-positive cocci comprised of 63.8 and 36.2 %, respectively. The cumulative incidences of neutrophil and platelet engraftment, acute or chronic graft versus host disease (GVHD) were comparable among the non-BSI, gram-negative bacilli BSI, and gram-positive cocci BSI groups. The cumulative incidence of transplant-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DFS) was similar between the non-BSI and the BSI groups. For subgroups analysis, TRM was lower in gram-positive cocci BSI patients compared with that of gram-negative bacilli BSI patients (8.3 vs 39.3 %) (p = 0.01) (HR = 0.39, p = 0.034), and the 5-year OS was higher in gram-positive cocci BSI cohort (79.1 vs 44.2 %) (p = 0.01) (HR = 0.36, p = 0.046). Our study demonstrated that, for acute leukemia patients who received CBT after myeloablative conditioning that omitted ATG, pre-engraftment BSI had no impact on engraftment, GVHD, TRM, relapse, and long-term survival. Due to the fact that gram-negative bacilli BSI was associated with poor outcomes compared with gram-positive cocci BSI, appropriate early empirical antimicrobial management strategies and better supportive care are required to decrease the gram-negative bacilli BSI-related mortality.