Infective endocarditis in a middle-income country: microbiological profile, culture-negative burden, and in-hospital mortality predictors in a 14-year tertiary-center cohort

Abstract Objectives To describe the clinical characteristics, microbiological profile, culture status, management, and in-hospital mortality predictors of infective endocarditis (IE) in a tertiary center from a middle-income country. Methods We conducted a retrospective cohort study including 143 adults with definite IE according to modified Duke criteria between 2011 and 2025. Demographic, clinical, microbiological, echocardiographic, and treatment variables were collected. Multivariable logistic regression was used to identify independent predictors of in-hospital mortality. Effect estimates are reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI). Results In-hospital mortality was 46/143 (32.1%). Blood cultures were positive in 96/143 (67.1%) and negative in 47/143 (32.9%). Staphylococcus aureus was the leading pathogen and showed the highest mortality proportion (16/25, 64.0%). In multivariable analysis, S. aureus infection (aOR: 6.78, 95% CI 2.35–19.58), native-valve endocarditis (aOR: 3.23, 95% CI 1.06–9.85), and increasing age (aOR: 1.04 per year, 95% CI 1.01–1.08) were independently associated with in-hospital mortality. These adjusted estimates should be interpreted with caution, as the model included 7 variables for 46 events (events-per-variable ratio 6.6). Surgery was formally indicated in 87 patients (60.8%) but performed in 73 (51.0%), indicating that not all patients with surgical indication underwent intervention. Conclusions IE in this cohort showed high all-cause in-hospital mortality, substantial culture-negative burden, and strong prognostic impact of S. aureus . Strengthening microbiological diagnosis and timely multidisciplinary management may improve outcomes.