Of 251 patients who were referred to the study center, 42 had prosthetic intracardial material, 4 had right-sided endocarditis, and 2 were younger than 18 years. Endocarditis was rejected in 28 patients. Of 175 remaining eligible patients, 52 (29.7%) were excluded: 27 patients in whom antimicrobial treatment had been started before study enrollment in the absence of CRP measurements, 3 patients who died before inclusion, and 22 patients who declined to provide informed consent. Table 1 gives demographic and clinical characteristics, infecting microorganisms, and site of infection in the remaining 123 patients. All patients fulfilled the Duke Endocarditis Service criteria for definite endocarditis. In 36 patients (29.3%), material obtained by cardiac surgery or at autopsy demonstrated histologic signs of active infection. Community-acquired IE was present in 107 patients (87.0%); in the other patients, IE was nosocomial (n = 9) or health care related (n = 7). Five patients had experienced a prior episode of endocarditis 8 months, 4.5 years, 5 years, 10 years, and 38 years before the current episode. Of 123 patients, 49 (39.8%) had concomitant serious disease at the time of admission, including kidney failure (n = 17 [8 required chronic dialysis]), diabetes mellitus with secondary complications (n = 15), autoimmune diseases requiring immunosuppressive medication (n = 14), cancer (n = 10), chronic obstructive pulmonary disease with chronic bronchitis (n = 5), and human immunodeficiency virus (n = 1). Some patients had more than 1 concomitant disease. Echocardiography was performed in all patients. Both transthoracic and transesophageal echocardiography were performed in 90 patients, transesophageal echocardiography only was performed in 17 patients, and transthoracic echocardiography only was performed in 16 patients. Echocardiography demonstrated 1 vegetation or more (n = 109), intracardiac abscess (n = 3), or a combination of both (n = 6); in 5 patients, no vegetations or abscesses were detected.