Antibiotic Treatment Duration for Isolated Methicillin-Susceptible Staphylococcus Aureus Native Tricuspid Valve Endocarditis: A Standardized Multidisciplinary Approach

Background: Isolated methicillin susceptible Staphylococcus aureus native tricuspid valve endocarditis (MSSA TVIE) is a serious complication of injection drug use with significant associated morbidity and cost. Guideline recommendations differ with respect to the optimal duration and route of antibiotic administration which can contribute to variations in clinical practice. We report the outcomes of treating MSSA TVIE endocarditis using a multidisciplinary team and cardiovascular infectious diseases consult service. Methods: Patient cases were identified from an institutional multidisciplinary endocarditis team registry in a single-center retrospective study. Demographics, treatment and outcomes data were recorded by study investigators. Results: Between September 7th, 2021, and September 7 ^th , 2024, 34 consecutive patients with definite isolated MSSA TVIE were identified. Patients were treated with antibiotics for a median duration of 28 days (IQR 11 – 41) of which half were treated with oral antibiotics for a median duration of 14 days. During the follow up period there was one relapsed infection within 30 days and one death contributing to a 2.9% in hospital mortality & 90-day mortality. In the study population there were high rates of active injection drug use (79.4%), prior history of infectious endocarditis (23.5%), patient-directed discharge (35.3%). and 90-day readmissions (35.3%). Conclusion Utilizing a standardized approach to patient care, including a cardiovascular infectious diseases consult service and multidisciplinary endocarditis team, patients with MSSA isolated TVIE without metastatic osteoarticular or spinal infections were successfully treated with antibiotic courses of 28 days or less with low-rates of mortality and relapsed infection at 90-days.