266 - Ceftriaxone Versus Cefazolin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteremia

Background: Few studies have evaluated the use of ceftriaxone (CRO) in the treatment of Methicillin-sensitive Staphylococcus aureus (MSSA) infections. Available studies include a small number of patients with MSSA bacteremia, with conflicting results and several limitations. The purpose of this study was to compare the safety and efficacy of CRO versus cefazolin (CFZ) for patients with MSSA bacteremia.

Methods: This was a multi-center, single health-system retrospective cohort study. Patients were included if they were at least 18 years old, had a primary episode of MSSA bacteremia within Saint Luke’s Health System and received CRO or CEFZ as definitive therapy for MSSA bacteremia. Patients were excluded if they had a previous MSSA bacteremia within 6 months, a polymicrobial infection, received combination antimicrobial therapy as definitive therapy, started treatment at outside hospital, treated for less than 72 hours, or deemed palliative or comfort care.  The primary endpoint was clinical cure at 7, 10, 14, and 28 days, or discharge, whichever came first. Secondary endpoints included time to clinical cure or discharge, treatment failure at 90 days, time to treatment failure, readmission due to recurrent MSSA bacteremia at 30 and 90 days, duration of bacteremia, discontinuation of definitive treatment due to adverse drug events, incidence of Clostridiodes difficile infection, and hospital length of stay.

Results: A total of 248 patients met inclusion criteria. Among these, 87 (35.1%) received CRO and 161 (64.9%) received CFZ as definitive therapy. Patient baseline and treatment characteristics are shown in Table 1. The primary outcome occurred in 75 (86.2%) patients in the CRO group vs 145 (90.1%) patients in the CFZ group (P= 0.359), even after adjusting for Charlson Comorbidity Index, Pitt bacteremia score and serum creatinine, (aOR=0.74, 95% CI 0.32 – 1.72; p=0.473). There were no differences in time to clinical cure or discharge, treatment failure at 90 days, or safety events between the two groups. Primary and secondary endpoints are included in Table 2.Table 1
Table 2


Conclusion: Our study suggests that there is no clinical difference between CRO and CFZ for the treatment of MSSA bacteremia. Further studies are needed to confirm these findings.