728Evaluation of Empirical Regimens Including Antistaphylococal Beta-lactam Antibiotics vs Vancomycin Monotherapy on Outcomes of Patients with Methicillin-Susceptible Staphylococcus aureus (MSSA) Bacteremia

Methods. This was a single-center retrospective study of patients with MSSA BSIs from April 2008-December 2013. Inclusion criteria were: receipt of ≥48 hours of empiric therapy; ≥1 positive blood culture with MSSA; first positive culture drawn within 24 hours of starting empiric antibiotics. Exclusion criteria consisted of: use of antiMRSA therapy for concomitant infection; polymicrobial BSI; use of other agents active against MSSA. The primary endpoint was clinical failure, a composite of 30-day mortality and persistent BSI ≥7 days. Logistic regression was performed to determine factors associated with the endpoint. Results. 339 charts of patients with S. aureus BSI were screened and 75 of these patients were included in the final analysis. Conclusion. This study does not show a significantly increased risk of clinical failure in patients who are treated with vancomycin monotherapy empirically. The lack of significant differences between groups may be due to insufficient power to detect a difference; therefore, a larger study evaluating the influence of empiric antibiotic choice for MSSA BSI is warranted. Disclosures. J. Gallagher, Cubist: Consultant, Consulting fee; Optimer: Scientific Advisor and Speaker’s Bureau, Consulting fee and Speaker honorarium; Astellas: Speaker’s Bureau, Speaker honorarium; Forest: Scientific Advisor and Speaker’s Bureau, Consulting fee and Speaker honorarium; Pfizer: Scientific Advisor, Consulting fee