965. The Efficacy of Oral Β-lactam Antibiotics as Step-down Therapy for Acute Pyelonephritis

BACKGROUND: Often, oral β-lactams have been avoided for the treatment of pyelonephritis due to data suggesting lower efficacy vs. currently recommended therapy. However, increasing resistance and concerns for collateral damage of primarily recommended oral agents have increased interest in the use of oral β-lactams for the treatment of pyelonephritis. Authors sought to assess the impact of oral step-down β-lactam therapy compared with an alternative oral agent (fluoroquinolone or trimethoprim-sulfamethoxazole) in patients with acute pyelonephritis requiring hospitalization. METHODS: This is an IRB-approved, multicenter, retrospective study of hospitalized patients with acute pyelonephritis in six hospitals within two healthcare systems who received an IV cephalosporin followed by step-down therapy with either a β-lactam or an alternative agent (i.e., fluoroquinolone or trimethoprim-sulfamethoxazole). We theorize that oral β-lactams are noninferior to alternative oral agents for step-down therapy for pyelonephritis requiring hospitalization. Treatment success was defined as lack of 30-day urinary system-related re-admission. We calculated that 89 patients were required in each group to achieve 80% power with a noninferiority margin of 15% and assuming a cure rate of 85% as reported in previous literature. RESULTS: A total of 188 patients were included in the study; 115 and 73 who received an oral β-lactam and an alternative oral agent, respectively. There was no difference in treatment success when comparing the two groups (113 [98%] vs. 70 [96%]; P = 0.38). The mean length of hospital stay, number of patients treated with ceftriaxone inpatient, and the duration of IV therapy was the same in both groups, though mean duration of oral therapy was longer in the oral alternative group compared with the oral β-lactam group (9.5 [+ 3.7] vs. 8.2 [+ 2.7] days, respectively; P = 0.02). Baseline characteristics other than mean age were the same, as reported in Table 1. CONCLUSION: When using 30-day urinary system-related readmission as a surrogate for treatment success, we found no difference between β-lactams vs. alternative agents for oral step down therapy for pyelonephritis requiring hospitalization. [Image: see text] DISCLOSURES: All Authors: No reported Disclosures.