Fluoroquinolone Prophylaxis for Febrile Neutropenia in Autologous Hematopoietic Cell Transplantation: Outcomes and Risk Factors

INTRODUCTION: Febrile neutropenia (FN) is a frequent complication following autologous hematopoietic cell transplantation (auto-HCT). Prophylactic use of fluoroquinolones (FQs) has been shown to reduce FN incidence; however, its routine use remains controversial due to increasing concerns regarding antimicrobial resistance and uncertain impact on clinically relevant outcomes. METHODS: We conducted a retrospective cohort study including adult patients who underwent auto-HCT at A.C.Camargo Cancer Center between 2016 and 2021. Patients were divided into two groups according to institutional prophylaxis policy: those who received levofloxacin prophylaxis during neutropenia between 2016 and 2018 (Px group, n = 201) and those who did not receive FQ prophylaxis between 2018 and 2021 (NPx group, n = 169). The primary outcome was the incidence of FN. Secondary outcomes included microbiologically documented infections, antimicrobial resistance patterns, and 30- and 100-day all-cause mortality. RESULTS: FN occurred more frequently in the NPx group compared with the Px group (92% vs. 81%, p = 0.002). There were no significant differences between groups in the rate of microbiologically documented infections (23% vs. 14%, p = 0.09), 30-day mortality (3% vs. 1%, p = 0.25), or 100-day mortality (3% vs. 2%, p = 0.48). Antimicrobial resistance profiles differed significantly: the Px group had a lower proportion of pan-susceptible isolates (17% vs. 61%) and higher rates of extended-spectrum β-lactamase-producing organisms (27% vs. 6%) and methicillin-resistant bacteria (36% vs. 10%) compared with the NPx group (all p < 0.001). CONCLUSION: Although FQ prophylaxis was associated with a lower incidence of FN after auto-HCT, it did not translate into reductions in short-term mortality and was associated with significantly higher rates of antimicrobial resistance. Based on these findings, our institution does not recommend routine FQ prophylaxis for patients undergoing auto-HCT.