Ceftriaxone versus cefazolin for the treatment of methicillin-susceptible Staphylococcus aureus bacteraemia

•Few studies have evaluated inpatient use of ceftriaxone for MSSA bacteraemia.•This retrospective multicentre study included adults with MSSA bacteraemia.•Study compared ceftriaxone versus cefazolin for treatment of MSSA bacteraemia.•No difference in rates of clinical cure between the two treatment groups.•No difference in secondary or safety outcomes between the two treatment groups. Few studies have evaluated the use of ceftriaxone (CRO) in the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) infections. The purpose of this study was to compare the safety and efficacy of CRO versus cefazolin (CZO) for patients with MSSA bacteraemia. This was a multicentre, single health-system, retrospective study. Adult inpatients were included if they had a primary episode of MSSA bacteraemia and received CRO or CZO as definitive therapy. The primary endpoint was clinical cure at 28 days or at discharge, whichever came first. Secondary endpoints included treatment failure at 90 days, time to treatment failure, re-admission due to recurrent MSSA bacteraemia, duration of bacteraemia, discontinuation of treatment due to adverse drug events, and Clostridioides difficile infection. A total of 248 patients were included, of which 87 (35.1%) received CRO and 161 (64.9%) received CZO. There was no difference in the primary outcome of clinical cure at 28 days or at discharge between the CRO and CZO groups [75 (86.2%) vs. 145 (90.1%); P = 0.359], even after adjusting for Charlson comorbidity index and Pitt bacteremia score (adjusted OR = 1.35, 95% CI 0.58–3.12; P = 0.49). There were no differences in time to clinical cure, treatment failure at 90 days or safety events between the two groups. In conclusion, our findings suggest no clinical difference between CRO and CZO for the definitive treatment of MSSA bacteraemia. Further prospective studies are needed to confirm these findings.