Factors Associated with Infective Endocarditis and Predictors of 3-month mortality of Patients with Viridans Streptococcal Bacteremia

Background: Viridans streptococci is a major pathogen of infective endocarditis. This study was conducted in order to investigate the factors associated with infective endocarditis and predictors for three-month mortality among patients with viridans streptococcal bacteremia (VSB). Materials and Methods: In this study, among 261 eligible patients diagnosed as VSB from January 2000 through June 2011 in a university-affiliated hospital, a retrospective analysis of 197 patients was conducted. All patients with VSB were classified into two groups according to sites of bacteremia; infective endocarditis and other infections. Demographic and clinical characteristics were reviewed through electronic medical records factors associated with infective endocarditis and predictors of three-month mortality in VSB patients were evaluated. Results: Of the 197 patients, 37 (18.8%) patients had viridans streptococcal infective endocarditis (VSIE) and 160 (81.2%) patients had VSB due to other infection. In logistic regression analysis, underlying valvular heart disease (odds ratio [ OR], 48.43; 95% confidence interval [CI], 5.77-406.38) and persistent bacteremia (OR, 46.32; 95% CI, 7.18-299.01) showed an independent association with VSIE. Three-month mortality rate was 21.7% in patients with VSB. In logistic regression analysis, previous steroid use (OR, 9.31; 95% CI, 1.34-64.52), previous immunosuppressive therapy (OR, 9.50; 95% CI, 2.13-42.30), hypotension at onset of bacteremia (OR, 7.72, 95% CI, 2.45-24.33), and Charlson comorbidity score >= 3 (OR, 4.53, 95% CI, 1.55-13.28) showed an independent association with three-month mortality in patients with VSB. Conclusions: VSB patients who have valvular heart disease or persistent bacteremia routinely require echocardiography. Previous steroid use, immunosuppressive therapy, hypotension, and higher Charlson comorbidity score suggested poor prognosis in patients with VSB.