Molecular Diagnosis of Infective Endocarditis: A Helpful Addition to the Duke Criteria

Infective endocarditis (IE) remains a disease of concern because of its relatively high morbidity and mortality if not treated aggressively. Its incidence rate is between 1.7 to 6.2 cases per 100,000 in the general population and has remained essentially unchanged in the last two decades. 1 Presently, there is a shift in the demographics of populations at risk, with IE being seen more often in intravenous drug users, 2 patients exposed to nosocomial settings, 3 and hemodialysis patients. These diagnostic guidelines include major and minor criteria, such as positive microbiological cultures, vegetations seen by echocardiography, fever, and the presence or absence of a predisposing heart condition. The Duke criteria have been found to be more sensitive than the von Reyn criteria in identifying IE cases as shown by Andrs et al. 9 in a study of 38 patients in a clinical internal medicine practice. The enhanced sensitivity was due to the incorporation of echocardiographic findings in the Duke criteria. However, the utility of the Duke criteria has not been adequately assessed in patients with proven or suspected prosthetic valve endocarditis (PVE) or in selected populations, such as patients with congenital heart disease, in patients on chronic dialysis, or in hospitalized patients with indwelling catheters and bacteremia. In a study by Ben-Ami et al., 8 the rate of hospital-associated IE was 27 cases per 100,000 persons, suggesting a broadening of the definition of hospital-acquired IE.