Nosocomial enterococcal endocarditis: a serious hazard for hospitalized patients with enterococcal bacteraemia

Enterococci are a major leading cause of infectious endocarditis and also a common cause of hospital-acquired bacteraemia, which is not believed to represent a serious hazard for the endocarditis. The incidence and risk factors for infectious endocarditis in patients with hospital-acquired enterococcal bacteraemia is determined.

Prospective analysis of 116 patients with enterococcal bacteraemia admitted to medical or surgical wards of a tertiary-care, university affiliated hospital during a period of 5 years. Echocardiography was performed when indicated by clinical criteria.

Seventy-five (61.4%) episodes were hospital-acquired and 47 (38.5%) were community-acquired. Most patients had one or more underlying chronic diseases and major abdominal (58.6%) or genitourinary (38.6%) surgery. Seventeen patients (14.6%) developed enterococcal endocarditis. By univariate analysis the risk factors associated with endocarditis were community-acquired infection (P 0.012); monomicrobial bacteraemia (P 0.006); three or more positive blood cultures (P < 0.001); underlying valvulopathy (P < 0.001); presence of a prosthetic valve (P < 0.001) and age (P 0.012). Six patients (8%) developed nosocomial endocarditis. In this group of patients, three or more positive blood cultures (P < 0.01), bacteraemia as a result of Enterococcus faecalis (P 0.007); underlying valvulopathy (P < 0.001) and presence of a prosthetic valve (P < 0.001) were associated with endocarditis. By logistic regression, the presence of underlying valvulopathy and three or more positive blood cultures were associated with endocarditis (OR 21.0; CI 95% 1.65-26.9; P 0.019).

The risk of developing infectious endocarditis in patients with hospital-acquired enterococcal bacteraemia is significant. Patients with underlying valvulopathy and three or more positive blood cultures with E. faecalis are prone to nosocomial enterococcal endocarditis.