Daptomycin and linezolid salvage therapy for persistent ampicillin-susceptible <i>Enterococcus faecalis</i> bacteremia in a patient with possible anaphylaxis to β-lactam and glycopeptide antimicrobials: A case report

Background: Enterococcus species are gram-positive organisms that are among the most prevalent causes of bacteremia with a urinary source. Combination therapy is considered for deep-seated enterococcal infections due to the occasionally poor bactericidal activity of cell wall–active agents, high failure rates, and synergistic activity. The use of daptomycin and linezolid as monotherapy or as combination therapy with β-lactams or aminoglycosides is well described in the literature; however, the efficacy of daptomycin and linezolid combination therapy is less clear. Method: Retrospective single-chart review and single-database narrative literature review. Results: We describe a 60-year-old man with persistent ampicillin-susceptible Enterococcus faecalis bacteremia secondary to a right ureteric stone. His management was complicated by a suspected anaphylactic reaction shortly after receiving vancomycin and ceftriaxone that progressed after receiving ampicillin and cefazolin, as well as delayed source control due to safety concerns withholding anticoagulation for concurrent high-burden bilateral pulmonary emboli, ultimately resulting in persistent bacteremia. His bacteremia cleared with combination therapy of daptomycin 10 mg/kg intravenously daily and linezolid 600 mg orally every 12 hours. A review of the literature of Ovid MEDLINE from 2000 to July 16, 2025, revealed limited reported use of combination daptomycin and linezolid for the microbiologic cure of enterococcal infection. Conclusion: The bacteremia cleared with combination daptomycin and linezolid therapy on day 9 of admission, prior to achieving source control with nephrostomy tube insertion 2 days later. The patient made a complete recovery.