Daptomycin Plus Oxacillin for Persistent Methicillin-Susceptible Staphylococcus aureus Bacteremia

• Published in: The Annals of pharmacotherapy Vol. 58; no. 4; pp. 360 - 365
• Main Authors: Kufel, Wesley D., Zagoria, Zoey, Blaine, Bruce E., Steele, Jeffrey M., Mahapatra, Rahul, Paolino, Kristopher M., Thomas, Stephen J.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01-04-2024
• Subjects: Adult; Anti-Bacterial Agents - adverse effects; Bacteremia - drug therapy; Bacteremia - microbiology; Carbapenems; Daptomycin - adverse effects; Humans; Methicillin; Oxacillin - adverse effects; Retrospective Studies; Staphylococcal Infections - drug therapy; Staphylococcal Infections - microbiology; Staphylococcus aureus; MSSA; daptomycin; infective endocarditis; oxacillin; Staphylococcus aureus; bacteremia
• ISSN: 1060-0280; 1542-6270
• DOI: 10.1177/10600280231189888

Background:
The preferred antibiotic salvage regimen for persistent methicillin-susceptible Staphylococcus aureus bacteremia (MSSAB) is unclear. Ertapenem with cefazolin or an antistaphylococcal penicillin has been primarily described, but identifying alternative carbapenem-sparing options may support antibiotic stewardship efforts and decrease the risk of antibiotic-associated Clostridioides difficile infection.
Objective:
We sought to evaluate the effectiveness and safety of daptomycin plus oxacillin (D/O) for persistent MSSAB.
Methods:
This was a single-center, retrospective cohort of patients with persistent MSSAB who received D/O between January 1, 2014, and January 1, 2023. Adult patients were included if they had blood cultures positive for MSSA ≥72 hours and received D/O combination for ≥48 hours. Patients were excluded if they were pregnant, incarcerated, or received another antibiotic considered to have excellent activity against MSSA. The primary outcome was time to MSSA bacteremia clearance post-daptomycin initiation. Secondary outcomes included microbiological cure, hospital length of stay, 90-day all-cause mortality, MSSA bacteremia-related mortality, 90-day readmission for MSSAB, and incidence of antibiotic-associated adverse effects. Time to MSSAB clearance post-D/O initiation was plotted using Kaplan-Meier estimation.
Results:
Seven unique patient encounters were identified including 4 with endocarditis. Despite a median MSSA bacteremia duration of 7.8 days, median clearance was 2 days post-daptomycin initiation. All achieved microbiological cure, and no adverse effects were reported. Ninety-day all-cause mortality, MSSAB-related mortality, and 90-day readmission for MSSAB occurred in 28.6%, 14.3%, and 14.3% of patients, respectively.
Conclusions and Relevance:
D/O was an effective, well-tolerated salvage regimen in this cohort and may represent a carbapenem-sparing option for persistent MSSAB.