159. Comparing Clinical Cure and Patient Outcomes Between Intravenous Therapy and Intravenous (IV)-to-Oral (PO) Step-down Therapy for Treatment of Gram-Negative Bloodstream Infections

BACKGROUND: There is a paucity of evidence surrounding optimal prescribing practices for the treatment of Gram-negative bloodstream infections (GNBSI). This study aimed to assess the appropriateness of IV-to-PO step-down therapy in the treatment of GNBSI. METHODS: A retrospective cohort study was conducted at the University of Cincinnati Medical Center and West Chest Hospital and included subject’s ≥18 years of age with GNBSI caused by Enterobacteriaceae spp. or Pseudomonas aeruginosa. The primary objective was to compare clinical cure rates between IV-only and IV-to-PO therapy, and to further assess differences in clinical cure rates amongst oral antibiotics of high, moderate, and low bioavailability. The study also aimed to identify factors associated with clinical cure, hospital length of stay, and emergence of multi-drug-resistant organisms (MDRO). RESULTS: Amongst 215 subjects screened, 99 subjects were included and 64 subjects met criteria for clinical cure. In the univariate analysis, the IV-to-PO group had a higher percentage of clinical cure than IV only therapy (82% vs. 48%, P = 0.001). Of note, the two study groups were significantly different in regards to intensive care status, Pitt bacteremia score, and primary site of infection. Upon further analysis, data from the multivariate logistic regression revealed that critical illness was the only significant factor that negatively impacted clinical cure (OR = 0.208; 95% CI 0.04–0.99; P = 0.049). A total of 49 subjects received oral antibiotics. Majority of patients (82%) in the IV-to-PO group received a moderately bioavailable oral antibiotic. No difference in respect to clinical cure rate was found between the three PO antibiotic bioavailability groups (P = 0.346). The median duration of hospital stay was shorter in the IV-to-PO compared with IV alone group (4 days vs. 9.5 days, respectively, P ≤ 0.001). There was a trend in emergence of MDROs with IV therapy compared with IV-to-PO therapy (10% vs. 2%, P = 0.204). CONCLUSION: IV-to-PO stepdown therapy compared with IV therapy alone was noninferior in clinical cure rates in the treatment of GNBSI and may result in fewer hospital days and less emergence of multidrug-resistant organisms. These conclusions are limited by significant differences in severity of illness between groups in this study. DISCLOSURES: All authors: No reported disclosures.