Role of fluoroquinolone prophylaxis in allogeneic hematopoietic cell transplantation in regions with a high prevalence of fluoroquinolone resistance

INTRODUCTION: The role of fluoroquinolone (FQ) prophylaxis in preventing gram-negative bacilli (GNB) bacteremia, graft-versus-host disease (GVHD), and overall survival (OS) after allogeneic hematopoietic cell transplantation (allo-HCT) is debatable and may differ in settings with low and high prevalences of FQ resistance. In this study, we aimed to answer this question in regions with high FQ resistance. METHODS: This single-center retrospective study included all consecutive allo-HCT recipients aged ≥12 years from 2012 to 2021. Allo-HCT recipients until 2016 were administered FQ prophylaxis (levofloxacin). After 2016, the institutional protocol was modified to no antibiotic prophylaxis. Data were retrieved from patient records for disease and transplant characteristics, the incidence of GNB bacteremia, duration of parenteral antibiotics, hospitalization duration, acute GVHD, and OS. RESULTS: A total of 135 allo-HCT recipients (43 in the FQ-prophylaxis cohort and 92 in the no-antibiotic prophylaxis cohort) were analyzed in this study. The two cohorts were matched for age (median, 26 vs. 24.5 years; p = 0.8). The no-antibiotic prophylaxis cohort had a higher proportion of malignant diagnoses (80% vs. 58%, p = 0.01), haploidentical transplants (46% vs. 14%, p = 0.004), and posttransplant cyclophosphamide exposure (46% vs. 14%, p = 0.003) than did the FQ cohort. Despite this, the incidence of GNB bacteremia was not significantly different between the two cohorts (37% vs. 34%, p = 0.6). There were no differences in parenteral antibiotic use or hospitalization duration, as well as the incidence of acute GVHD (53% vs. 53%, p = 0.3). The 1-year OS was similar between the two cohorts (66% vs. 67%, p = 0.6). CONCLUSION: This study shows that FQ prophylaxis did not affect the incidence of GNB bacteremia, parenteral antibiotic use, hospitalization duration, acute GVHD, and OS post-allo-HCT.