296. IV-to-PO Antibiotic Step-down Therapy for Treatment of Uncomplicated Streptococcal Bloodstream Infections

Abstract Background Beta-lactams are the drug of choice for uncomplicated Streptococcal bloodstream infections (BSIs). However, due to the low bioavailability of oral beta-lactams, it’s unclear whether de-escalation from IV to PO therapy is safe and effective. Our objective was to compare the efficacy and safety of step-down IV-to-PO antibiotic therapy to IV-only treatment of uncomplicated Streptococcal BSIs. Methods This was a retrospective study at a level-1, academic medical center in New Mexico of patients ≥ 18 years of age treated for uncomplicated Streptococcal BSI between January 2017 and December 2019. The primary outcome was clinical failure in patients receiving IV-only therapy compared to IV-to-PO step-down therapy. Clinical failure was defined as having at least one of the following: persistent bacteremia, 30-day reinfection at any site or new-onset sepsis, 30-day BSI recurrence, or 30-day all-cause mortality. Secondary outcomes include 30-day all-cause readmission, 30-day antibiotic-related side effects, 30-day C. difficile-associated diarrhea and hospital length of stay (HLOS). Results A total of 98 patients were included: 51 in the IV-to-PO group and 47 in the IV-only therapy group. The median age for both groups was 61 years; 65% patients were male, and 72% were Caucasian. BSIs were predominantly associated with respiratory infections (24.5%). Streptococcus pneumoniae (29.6%) was the most common pathogen. Nine patients (19.1%) in the IV-only group and none in the IV-to PO group experienced a clinical failure. 30-day reinfection at any site or new-onset sepsis (88.9%) was the primary cause of clinical failures. Fourteen patients (14.3%) were readmitted due to any cause within 30 days, 6 patients (11.8%) from the IV-to-PO and 8 (17%) from the IV-only group. Patients in the IV-to-PO group had a shorter duration of therapy than patients in the IV-only group (13 vs. 15 days, p=0.001), and decreased HLOS (5 vs. 12 days, p< 0.001). Clinical failure was not statistically different when assessed for co-morbidities, source of infection, Pitt bacteremia score, documented BSI clearance, ICU admission or pathogen. Conclusion IV-to-PO step-down therapy appears to be a safe and effective alternative for treating uncomplicated Streptococcal BSIs in patients who are otherwise clinical stable. Disclosures Keenan L. Ryan, PharmD, PhC, Theravance (Advisor or Review Panel member)