1114. Oral β-lactams for the Treatment of Escherichia coli Bacteremia Secondary to Complicated Urinary Tract Infections Including Pyelonephritis

BACKGROUND: Complicated urinary tract infections (cUTI) including pyelonephritis may result in bacteremia, increasing the rate of morbidity and mortality. The Infectious Diseases Society of America recommends a fluoroquinolone as empiric therapy or trimethoprim/sulfamethoxazole as definitive therapy for acute pyelonephritis (AP). Oral β-lactams (BL) are considered sub-optimal based on historical efficacy data with aminopenicillins and variable bioavailability. Increasing resistance and toxicity with preferred agents, justifies further evaluation of oral BL for E. coli bacteremia secondary to urinary source. METHODS: This was a single-center, retrospective cohort study of patients with E. coli bacteremia secondary to AP or cUTI who received oral step-down therapy with a BL or non-BL. The primary outcome was the rate of clinical success defined by microbiological cure, clinical cure, and infection-related readmission. Secondary outcomes were time to oral step-down, total days of therapy, length of hospital stay, incidence of therapy escalation, 30-day readmissions, and antibiotic-associated adverse events. RESULTS: A total of 46 patients were included, with 23 patients in each group. The difference in clinical success between the BL and non-BL groups was not statistically significant (91.3% vs. 100%, P = 0.489). The most frequent oral step-down agents prescribed were cephalexin and ciprofloxacin. The median time to oral step-down was significantly lower in the non-BL group (4.39 vs. 3.41 days, P = 0.038), and the median duration of therapy in each group was 15 days. No patients required therapy escalation after oral step-down or had infection-related readmission within 30 days of discharge. CONCLUSION: The observed clinical success rate of 91.3% remains consistent with previous studies evaluating oral BL as step-down therapy for Enterobacteriaceae bloodstream infections. The results of this study support the safety and efficacy of oral BL as step-down therapy for E. coli bacteremia due to cUTI, although larger studies may be beneficial. DISCLOSURES: All authors: No reported disclosures.