Clinical characteristics and analysis of prognostic factors in methicillin-resistant Staphylococcus aureus endocarditis: A retrospective multicenter study in Japan

Background Infective endocarditis (IE) caused by MRSA (methicillin-resistant Staphylococcus aureus) is associated with a high mortality rate. This study aimed to elucidate the characteristics of patients with MRSA-IE in Japan and identify the factors associated with prognosis. Methods This retrospective study included patients with a confirmed diagnosis of IE caused by MRSA, between January 2015 and April 2019. Results A total of 65 patients from 19 centers were included, with a mean age of 67 years and 26% were female. Fifty percent of the patients with IE were had nosocomial infections and 25% had prosthetic valve involvement. The most common comorbidities were hemodialysis (20%) and diabetes (20%). Congestive heart failure was present in 86% of patients (NYHA class I, II: 48%; III, IV: 38%). The 30-day and in-hospital mortality rates were 29% and 46%, respectively. Multi-organ failure was the primary cause of death, accounting for 43% of all causes of death. Prognostic factors for in-hospital mortality were age, disseminated intravascular coagulation, daptomycin and/or linezolid as initial antibiotic therapy, and surgery. Surgical treatment was associated with a lower mortality rate (odds ratio [OR], 0.026; 95% confidence interval [CI], 0.002-0.382; p=0.008 for 30-day mortality and OR, 0.130; 95% CI; 0.029-0.584; p=0.008 for in-hospital mortality). Conclusion Mortality due to MRSA-IE remains high. Surgical treatment is a significant prognostic predictor of MRSA-IE.