Persistent Fever, Splinter Hemorrhages, and an Aortic Valve Abscess

A 29-year-old man presents with 1 month of fever, drenching sweats, malaise, and reduced appetite. He reports daily temperatures at home, progressive fatigue, and an unintentional 4-kg weight loss. He has no known valvular disease and takes no chronic medications.

He recently returned from visiting family in a rural area where he consumed unpasteurized goat cheese and helped care for sheep and goats. He denies injection drug use. On examination, he is febrile to 39.3 degrees C, tachycardic, and has splinter hemorrhages under several fingernails. Cardiac auscultation reveals a new diastolic murmur.

Laboratory studies show a white blood cell count of 8.9 x 10^9/L, hemoglobin 12.6 g/dL, platelets 214 x 10^9/L, C-reactive protein 29 mg/dL, and erythrocyte sedimentation rate 58 mm/hour. Aspartate aminotransferase is 42 U/L and alanine aminotransferase is 39 U/L. Transthoracic echocardiography demonstrates a friable vegetation on the aortic valve with an aortic root abscess. Four blood culture sets remain negative at 48 hours, but one bottle later grows a small gram-negative coccobacillus after prolonged incubation. A standard tube agglutination test returns positive at a titer of 1:640.