Rise of the beta-lactams: a retrospective, comparative cohort of oral beta-lactam antibiotics as step-down therapy for hospitalized adults with acute pyelonephritis.

Objective: The aim of this study was to determine if oral beta-lactam therapy is non-inferior to alternative therapy at discharge following inpatient treatment with an IV cephalosporin for acute pyelonephritis. Design: Institutional Review Board (IRB)-approved, multicenter, retrospective, non-inferiority cohort (15% non-inferiority margin). Setting: Six hospitals within two healthcare systems. Patients: Hospitalized patients admitted to the medical floor with acute pyelonephritis without urologic abnormalities who received cefazolin or ceftriaxone followed by step-down therapy. Methods: Patients were discharged with either an oral beta-lactam or an oral alternative agent (ie, fluoroquinolone or trimethoprim-sulfamethoxazole) to complete therapy. The primary objective was treatment failure defined as a composite of hospital readmission or an ED visit for a urinary cause within 30 days of discharge of the index hospitalization. Data were extracted manually from the electronic medical record. Results: A total of 211 patients were included; 122 received an oral beta-lactam and 89 received an oral alternative agent at discharge. There was no difference in 30-day treatment failure between the two groups (4.9% vs 5.6% for oral beta-lactams vs oral alternatives, respectively. Absolute difference = 0.7%; 95% CI -5.4% to 6.8%; Conclusions: In non-ICU patients admitted for pyelonephritis without urologic abnormalities, oral beta-lactams were non-inferior to oral alternatives for step-down therapy. In finding non-inferiority between the regimens, we show the feasibility of administering oral beta-lactams to complete therapy for acute pyelonephritis.