S1638 INTERRUPTING QUINOLONE PROPHYLAXIS IN HEMATOLOGIC PATIENTS WITH PROLONGED NEUTROPENIA: AN OBSERVATIONAL STUDY

Background: The use of quinolone prophylaxis of bacterial infection in prolonged profound neutropenia in hematological patients has been linked to an increased frequency of infection by multiresistant bacteria. This has led some centers to discontinue quinolone prophylaxis in these patients, although the experience of this course of action is currently limited. Aims: Analyze the clinical and microbiological consequences of the discontinuation of quinolone prophylaxis in hematologic patients with prolonged neutropenia (>6 days). The primary endpoints were overall mortality during hospitalization and the incidence of febrile neutropenia (FN). Secondary endpoints were to evaluate the incidence of bacteremia during the period of neutropenia specifically and bacteremia by gram‐negative bacilli resistant to carbapenem (CR‐GNB), with extended‐spectrum beta‐lactamase (ESBL‐GNB), or resistant to quinolones (QR‐GNB). Methods: Retrospective observational cohort study pre and post‐intervention. There were included all patients admitted into the hematology service with neutropenia exceeding six days of duration during periods comprised between April 1 and 31 December 2015 (pre‐intervention), and between April 1 and 31 December 2017 (post‐intervention). In addition to clinical parameters, the degree of adhesion of the intervention was recorded as the removal of prophylaxis. Results: A total of 694 hospital admission were reviewed, 184 episodies of patients with prolonged neutropenia (more than 6 days) were selected (91 in the pre‐intervention and 93 in period post‐intervention period). There were no significant differences in basic clinical characteristics of both groups: days of neutropenia (10 days [interquartile range (IQR) 8 to 15] vs 11 days [IQR 8 to 15 days]; p = .82) refractory disease to chemotherapy (6.6% vs 5.4% neoplasia; p = 0.73) and hospital stay (20 days [IQR 15 to 30] vs 20 days [IQR 15–27 Days]; p = 0.354). Adherence to the elimination of prophylaxis was 78%. Overall mortality in admission was 4.91 per 1000 days stay in the pre‐intervention vs. 2.31 in the post‐intervention period (p = 0.31). FN incidence was 0.71 episodes per 10 days of neutropenia vs 0.72 (p = 0.55). The incidence of bacteremia during neutropenia was 1.67 vs 2.58 for every 100 days of neutropenia (p = 0.17). While the incidence of bacteremia by MDR GNB (combining CR and ESBL GNB) was 0.91 vs. 0.45 for every 100 days of neutropenia (p = 0.17). The incidence of bacteremia by CR‐GNB was 0.44 vs 0.17 episodes per 100 days of neutropenia (p = 0.24) and for ESBL‐GNB 0.53 vs. 0.08 (p = 0.05), respectively. In addition, the incidence of bacteremia by FRQ‐GNB was 0.71 vs. 0.63 (p = 0.78), respectively. Thirty‐day bacteremia related mortality did not differ between time periods. None of the outcomes differed when excluding the 22% of patients who received FRQ in the post‐intervention prophylaxis period. Summary/Conclusion: The withdrawal of quinolone prophylaxis in prolonged neutropenia associated with hematological malignancies is a safe strategy with no impact on mortality. According to our experience, patients who do not take quinolones as a bacterial prophylaxis have a slightly higher risk of bacteremia during neutropenia with no statistical significance, with a lower incidence of bacteremia due to multiresistant microorganisms.