Evaluation of outcomes associated with antipseudomonal beta-lactams for treatment of methicillin-susceptible

Background: Treatment of methicillin-susceptible Objectives: To determine whether differences in outcomes exist between patients with MSSA bacteremia treated with cefazolin/oxacillin (standard of care; SOC) versus APBLs. Design: Retrospective cohort study. Methods: Adult and pediatric patients hospitalized between June 2016 and June 2023 with at least one positive blood culture for MSSA who received at least 14 consecutive days of inpatient therapy with cefazolin, oxacillin, cefepime, piperacillin-tazobactam, or meropenem were included. Patients who received APBLs were compared to those who received SOC. The primary outcome was composite clinical failure (i.e., 30-day all-cause mortality and/or bacteremia recurrence within 30 days). Secondary outcomes included 60-day all-cause mortality, intensive care unit and hospital length of stay, 30-day readmission, time to bacteremia clearance, time to mortality, and adverse events (i.e., Results: One hundred patients were included, with 50 patients in each group. The most common source of bacteremia was catheter-related (28% total), and twice as many patients met criteria for complicated MSSA bacteremia in the SOC versus APBL group (80% vs 40%, Conclusion: No differences in mortality or bacteremia recurrence were identified among patients with MSSA bacteremia treated with APBLs compared to SOC. Larger studies should be performed to confirm these findings.