The Characteristics of Febrile Neutropenia among Allogeneic Hematopoietic Stem Cell Transplant Recipients on Levofloxacin Prophylaxis

Abstract

Background. Data on febrile neutropenia (FN) among recipients of allogeneic hematopoietic stem cell transplant (allo-HSCT) on prophylactic levofloxacin (LVFX) are limited. Methods. Retrospective analysis of FN among allo-HSCT recipients (age, ≥16 years) who received 500 mg/day of oral prophylactic LVFX was conducted between January 2011 and September 2014. Causative strains were identified using VITEK2 and WalkAway 96 SI. Antibiotic susceptibility were determined by the current breakpoints standardized by the CLSI. Results. During the study period, 260 of the 262 allo-HSCT recipients who received prophylactic LVFX had FN. Prophylactic LVFX was changed to any one of the anti-pseudomonal β-lactams (APBLs) for all 260 recipients immediately after obtaining ≥ 2 sets of blood cultures at the onset of the first FN episode. Cefepime was most frequently used in these patients (87%). Most common underlying disease was acute leukemia (64%). Of the 260 recipients, 184 received cord blood transplantation (CBT). Bacteremia at the first FN episode occurred in 109 (42%) of the 260 recipients with FN; 17 of them had polymicrobial bacteremia. Causative organisms identified were Viridans group streptococci (VGS) (41), coagulase negative staphylococci (33), Gram-negative rods (GNRs) (20), and others (33). Only 1 patient was infected with Methicillin-resistant Staphylococcus aureus (MRSA), and none with vancomycin-resistant enterococci (VRE). Of the 41 VGS strains, only 1 was not susceptible to APBLs. Six of the 20 causative GNR strains were extended-spectrum β-lactamase producers. The independent risk factors for the occurrence of bacteremia at the first FN episode were high-risk transplantation (P < 0.001), ≥5 days of severe neutropenia (P < 0.001), and total body irradiation (P = 0.013). CBT was not an independent risk factor. The crude 30-day mortality rate did not differ significantly between those with bacteremia (10%) and those without (6.0%) (P = 0.22). Conclusion. Severe underlying conditions and immune status were associated with the occurrence of bacteremia in patients who underwent allo-HSCT. Bacteremia was not a major cause of death in this setting where APBLs non-susceptible VGS, MRSA, and VRE infections were rare.