Daptomycin Plus Oxacillin for Persistent Methicillin-Susceptible Staphylococcus aureus Bacteremia

Area of Science:

• Infectious Diseases
• Pharmacology
• Clinical Medicine

Background:

• The optimal antibiotic salvage regimen for persistent methicillin-susceptible Staphylococcus aureus bacteremia (MSSAB) remains undefined.
• Current approaches often involve carbapenems, raising concerns about antibiotic stewardship and Clostridioides difficile infection risk.
• Alternative carbapenem-sparing options are needed to manage persistent MSSAB effectively and safely.

Purpose of the Study:

• To evaluate the efficacy and safety of daptomycin plus oxacillin (D/O) as a salvage therapy for persistent MSSAB.
• To assess the time to bacteremia clearance and associated clinical outcomes in patients receiving D/O.

Main Methods:

• A single-center, retrospective cohort study included adult patients with persistent MSSAB (≥72 hours positive blood cultures) treated with D/O for ≥48 hours.
• Exclusion criteria included pregnancy, incarceration, or concurrent use of other highly active MSSA antibiotics.
• Primary outcome was time to MSSA bacteremia clearance; secondary outcomes included microbiological cure, length of stay, mortality, and adverse events.

Main Results:

• Seven patient encounters were analyzed, with four involving endocarditis.
• Despite a median bacteremia duration of 7.8 days, median clearance was achieved in 2 days post-D/O initiation.
• All patients achieved microbiological cure with no reported adverse effects; 90-day mortality and readmission rates were 28.6% and 14.3%, respectively.

Conclusions:

• Daptomycin plus oxacillin (D/O) demonstrated effectiveness and good tolerability as a salvage regimen for persistent MSSAB.
• This combination represents a potential carbapenem-sparing alternative for managing difficult-to-treat MSSAB infections.
• Further research in larger cohorts is warranted to confirm these findings.