Clinical outcome of combination of vancomycin and ceftaroline versus vancomycin monotherapy for treatment of methicillin resistant Staphylococcus aureus bloodstream infection.

Background: The role of combination therapies for serious methicillin-resistant Staphylococcus aureus (MRSA) infections is widely debated.

Methods: This retrospective cohort study included adults with MRSA bacteraemia treated between January 1, 2013, to December 31, 2022. Patients receiving combination therapy with vancomycin and ceftaroline were matched in a 2:1 ratio with those on vancomycin monotherapy based on bacteraemia source and illness severity. The primary outcome was frequency of bacteraemia recurrence. Secondary outcomes were all cause 30/90-day mortality, recurrence or mortality at 30/90 days and in hospital length of stay.

Results: Of 57 patients included, 37 (65%) were in the combination group. The overall intensive care unit admission rate was 63.2% (36/57) and the Pitt Bacteraemia Score was 1 [0-4] at the time of diagnosis. The most common source of infection was endovascular/endocarditis (n = 36, 63.2%). Demographic and clinical characteristics were similar between the monotherapy and combination group of patients, except for higher body mass index (32.5 [25.5-36.4] vs. 24.4 [20.9-29], p = 0.004) and a greater immunosuppression prevalence (3 (15%) vs. 0 (0%), p = 0.039) in monotherapy group. There was no significant difference in bacteraemia recurrence (3 (15%) vs. 4 (10.8%), p = 0.7) or all-cause 30-day mortality (3 (15%) vs. 4 (10.8%), p = 0.7) between the two groups.

Conclusion: The results of this study are limited by a retrospective observational design; however, combination of vancomycin and ceftaroline for MRSA bacteraemia was not associated with lower bacteraemia recurrence or mortality compared to vancomycin monotherapy.