Staphylococcus aureus drives high hospital mortality in infective endocarditis cohort

Adults admitted to a tertiary hospital in a middle-income country with definite infective endocarditis died in hospital in nearly one in three cases, according to a retrospective cohort study published in Annals of Clinical Microbiology and Antimicrobials. The analysis, covering admissions between 2011 and 2025, found that infection with Staphylococcus aureus, native-valve endocarditis and increasing age were independently associated with in-hospital death.

The study included 143 adults whose diagnoses met the modified Duke criteria for definite infective endocarditis. The researchers collected demographic, clinical, microbiological, echocardiographic and treatment variables and used multivariable logistic regression to identify independent predictors of in-hospital mortality, reporting effect estimates as adjusted odds ratios with 95% confidence intervals.

In-hospital mortality was 46 of 143 patients, or 32.1%. Blood cultures were positive in 96 of 143 patients (67.1%) and negative in 47 of 143 (32.9%), meaning that nearly one third of cases had no culture confirmation, a substantial culture-negative burden that the authors highlight as a diagnostic challenge in this setting.

Staphylococcus aureus was the leading pathogen identified in the cohort and also showed the highest mortality proportion among the detected organisms, with 16 of 25 patients infected by this bacterium dying in hospital, a mortality proportion of 64.0%.

In the multivariable analysis, S. aureus infection was associated with roughly a sevenfold increase in the odds of in-hospital death (adjusted odds ratio 6.78, 95% CI 2.35–19.58). Native-valve endocarditis was also independently associated with mortality (aOR 3.23, 95% CI 1.06–9.85), as was increasing age, with an adjusted odds ratio of 1.04 per year (95% CI 1.01–1.08).

The authors themselves urge caution in interpreting these adjusted estimates.

Surgical management was a notable gap in the cohort. Surgery was formally indicated in 87 patients, or 60.8% of the cohort, but was performed in 73 patients, or 51.0%, indicating that not all patients with a surgical indication underwent intervention. The study was observational and did not evaluate the effectiveness of the surgical protocol itself; it documented the gap between indication and performance.

The authors conclude that infective endocarditis in this cohort showed high all-cause in-hospital mortality, a substantial culture-negative burden, and a strong prognostic impact of S. aureus. They suggest that strengthening microbiological diagnosis and timely multidisciplinary management may improve outcomes, a statement of planned direction rather than a demonstrated effect of any intervention.

Several limitations should be kept in mind when reading these findings. The study is retrospective and single-center, so its results describe one tertiary referral hospital over 14 years and may not generalize to other settings or to primary-care populations. The article is being shared as an early-access, peer-reviewed accepted version that carries a permanent DOI and remains subject to further editorial edits before the final version of record is published.

Subject of Research: Microbiological profile and in-hospital mortality predictors of infective endocarditis in a tertiary-center cohort from a middle-income country

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

Article References: Pavia-Velandia, P. X., Morales-Pertuz, C., León-León, N. G., Garzón-Rodríguez, J. D., Molano-González, N., Rodríguez-Aparicio, E. E., & Rodríguez-Lima, D. R. (2026). Infective endocarditis in a middle-income country: microbiological profile, culture-negative burden, and in-hospital mortality predictors in a 14-year tertiary-center cohort. Annals of Clinical Microbiology and Antimicrobials. https://doi.org/10.1186/s12941-026-00887-y

Image Credits: AI Generated

DOI: 10.1186/s12941-026-00887-y

Keywords: infective endocarditis, Staphylococcus aureus, culture-negative endocarditis, in-hospital mortality, retrospective cohort, modified Duke criteria, native-valve endocarditis, blood cultures, middle-income country, tertiary care, multivariable logistic regression, cardiac surgery