Enterococci are common organisms associated with endocarditis, but infection by
Case ReportIn September 2014, a 74-year-old man was admitted to our institution with a 2-month history of intermittent fever, malaise, weight loss, and anorexia. He had a long history of hypertension controlled successfully with angiotensin-converting enzyme inhibitors and diuretic agents. Nine months earlier, the patient had undergone aortic valve replacement with a Trifecta aortic pericardial valve (St. Jude Medical, Inc.; St. Paul, Minn) for the treatment of severe aortic valve stenosis. About one month before his current admission, the frequency of his fever increased and amoxicillin (2 g/d) was administered without benefit. The physical examination upon current admission revealed an axillary temperature of 37.1 °C, a blood pressure of 130/80 mmHg, and an oxygen saturation of 98% on ambient air. The patient had no Janeway lesions or Osler nodes. Cardiac auscultation revealed a diastolic murmur at the right sternal border. Laboratory test results were as follows: 6.9 leukocytes/mL (neutrophils, 70%); hemoglobin, 8.5 g/dL; platelets, 101/mL; C-reactive protein, 12,458 mg/dL; and an erythrocyte sedimentation rate of 115 mm/hr. Renal function and hepatic enzyme levels were normal. Urine culture results were negative.Chest radiographs and ultrasonograms of the abdomen showed no abnormal findings. A transthoracic color-flow Doppler echocardiogram (TTE), performed through a poor acoustic window, revealed left ventricular hypertrophy and a large vegetation on the prosthetic aortic valve, with mild-to-moderate regurgitation (Fig. 1). A transesophageal echocardiogram (TEE) confirmed that the prosthetic aortic valve was 9 mm in diameter at the noncoronary cusp (Fig. 2). On the basis of the presence of fever and a vegetation on the aortic bioprosthetic valve, together with the characteristics of the laboratory results, our primary diagnosis was infective endocarditis.On the day of our patient's admission, we drew blood for 3 sets of cultures and began empirical intravenous treatment with the antibiotic ceftriaxone (2 g/d). After 72 hours, all 3 blood cultures yielded E. durans, which antibiotic susceptibility testing showed was susceptible to teicoplanin (minimal inhibitory concentration [MIC]= 1 mg/dL), vancomycin (MIC=1 mg/dL), linezolid (MIC <2 mg/dL), and gentamicin (MIC <500 mg/dL). On the basis of these results, and in accordance with European Society of Cardiology guidelines on the prevention, diagnosis, and treatment of infective endocarditis, 1 we suspended treatment with ceftriaxone and substituted a combi-
