LAUSR

Abstract Background Transition from intravenous (IV) to oral (PO) antibiotics is common practice in patients with Gram-positive bloodstream infections (GP-BSI); however, clinical data evaluating IV to PO switch options are lacking. The objective of this study was to examine effectiveness of PO antibiotics for definitive treatment GP-BSI, with a focus on bioavailability (BA). Methods This was a single-center, retrospective cohort study of adult inpatients admitted to an 874-bed academic medical center in Charlotte, NC between September 1, 2014 and August 31, 2017. Patients with a GP-BSI who received appropriate antibiotic therapy with at least one third of their total course administered PO were included. Patients with GP-BSI caused by staphylococcal species were excluded. The primary endpoint was clinical failure in patients receiving high (≥90%) vs. low (<90%) BA agents. Secondary endpoints included clinical failure stratified by antibiotic group, bactericidal vs. bacteriostatic agents, and organism. Chi-square and Fisher’s exact tests were used to examine clinical failure. Results One hundred three patients were included, 26 in the high BA group, and 77 in the low BA group. The median age was 58, 51% were women, 74.8% of patients had streptococcal bacteremia (26.2% S. pneumoniae), with pulmonary being the most common source (30.1%). There were no major differences in baseline demographic and clinical characteristics between groups. The median treatment duration with IV antibiotics was 4 and 5 days in the high and low BA groups, respectively (P = 0.12). There was no statistically significant difference in clinical failure in the high vs. low BA groups (19% vs. 23%, P = 0.66, respectively). Clinical failure stratified by antibiotic group, bacteriostatic vs. bactericidal agent (OR 1.43, CI 0.26–7.90), and organism also did not yield statistically significant differences. Conclusion These data demonstrate similar rates of clinical failure among patients definitively treated with high or low BA agents for GP-BSI. High BA agents such as fluoroquinolones may not be needed for all patients with GP-BSI, where more targeted β-lactam therapies may be appropriate. Additional prospective studies with larger sample sizes are needed to further validate these conclusions. Disclosures All authors: No reported disclosures.