Monotherapy as Effective as Dual Therapy for Methicillin-Resistant Staphylococcus aureus

Patients who were switched from dual therapy to monotherapy for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) did not differ for composite 60-day clinical outcomes compared with patients undergoing combination therapy. These findings from a retrospective cohort study were published in Open Forum Infectious Diseases.

Patients (N=140) admitted to the Ohio State University Wexner Medical Center with index MRSA between 2011 and 2019 were retrospectively assessed for 60-day clinical outcomes. All patients received dual therapy of ceftaroline and daptomycin for at least 72 hours. Patients who were maintained on dual therapy for at least 10 days were assigned to the combination cohort (n=66), and patients who were switched to monotherapy were assigned to the monotherapy cohort (n=74).

The monotherapies included daptomycin (n=30), vancomycin (n=26), and ceftaroline (n=18).

Patients in the combination and monotherapy cohorts were 53% and 49% women, had a median age of 42 (interquartile range [IQR], 32-55) and 50.5 (IQR, 37-63) years, and 74% and 81% were White, respectively. The combination cohort included more patients with a history of intravenous drug use (58% vs 36%; P =.01) and fewer patients with chronic kidney disease (18% vs 38%; P =.01) or diabetes mellitus (17% vs 38%; P =.005).

The composite outcome of 60-day recurrence, readmission, or infection-related mortality occurred among 21% of the combination and 24% of the monotherapy groups (P =.66). The rates of MRSA recurrence (3% vs 7%; P =.45), readmission (20% vs 18%; P =.75), and infection-related mortality (2% vs 5%; P =1) did not differ significantly for the combination and monotherapy cohorts, respectively.

The median inpatient stay for patients receiving dual therapy was 26 (IQR, 20-41) days and for those receiving monotherapy was 24.5 (IQR, 16-33) days (P =.08).

A total of 3 patients had adverse reactions: 1 had bone marrow suppression, 1 had neutropenia, and 1 had pedal edema. Rates of these events did not differ on the basis of treatment (P =.47).

Among only patients who developed endocarditis, epidural abscess, or osteomyelitis (combination: n=50; monotherapy: n=41), the rate of the composite outcome was 26% and 17% (P =.31) for the combinatorial and monotherapy cohorts, respectively.

This study was limited by its small sample size and single-center, retrospective design.

These data indicated the composite 60-day outcome of recurrence, readmission, and mortality was not significantly different for patients who were maintained on the dual therapy of ceftaroline and daptomycin vs those for whom treatment was de-escalated to a monotherapy of daptomycin, vancomycin, or ceftaroline. This pattern was similar among patients who developed endocarditis, epidural abscess, or osteomyelitis.

Reference

Nichols CN, Wardlow LC, Coe KE, Sobhanie MME. Clinical outcomes with definitive treatment of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia with retained daptomycin and ceftaroline combination therapy versus de-escalation to monotherapy with vancomycin, daptomycin, or ceftaroline. Open Forum Infect Dis. 2021;ofab327. doi:10.1093/ofid/ofab327