278. Comparison of Oral Cephalexin Versus Oral Levofloxacin for Treatment of Uncomplicated Enterobacterales Bacteremia

Abstract

BackgroundAerobic gram-negative rods (GNR) are a common cause of bloodstream infections. While the use of oral antibiotics as step-down therapy for GNR bacteremia is generally accepted, there is debate as to which agents are best. Fluoroquinolones have high oral bioavailability but also have concerns for toxicity, while oral beta-lactams have lower achievable blood concentrations and require more frequent dosing. At Kaweah Delta Medical Center, patients are transitioned from IV antibiotics to oral levofloxacin or cephalexin. The purpose of this study is to determine if these two oral agents are comparable when used as step-down therapy for uncomplicated GNR bacteremia.MethodsThis was a single-center, retrospective study of adult patients who were admitted from May 2018 - May 2019 with a positive GNR blood culture. The primary objective was to assess treatment failure defined as a composite outcome of readmission due to recurrent bacteremia or mortality within 60-days. Secondary outcomes included subsequent Clostridioides difficile infection, emergence of resistant GNR bacteria, and hospital length of stay.ResultsA total of 82 patients met inclusion criteria. The combined median age of both treatment groups was 58.2 years (interquartile range [IQR], 46.7–73.5) and greater than 60% of patients were female. Most patients were Hispanic (45.1%) or non-Hispanic white (43.9%). The most common documented source of GNR bacteremia was the urinary tract (74.4%), and the most frequently recovered organism was Escherichia coli (78.0%). Patients were treated with IV antibiotics for a median treatment duration of 4 days (IQR, 4–5) and oral antibiotics for a median treatment duration of 10 days (IQR, 7.3–11) and 9 days (IQR, 7–11) for cephalexin and levofloxacin, respectively. The composite outcome occurred in 2 patients (4.3%) from the cephalexin group and 0 patients from the levofloxacin group (p=0.50). Positive cultures for resistant GNR were found for 3 patients in the cephalexin group. No patients developed subsequent C. difficile infections. ConclusionPatients who received cephalexin or levofloxacin did not have a significant difference in the composite primary outcome. These findings suggest that oral cephalexin is an effective step-down option to treat uncomplicated GNR bacteremia.Disclosures All Authors: No reported disclosures