A 19-year-old man has had a low-grade fever for 3 weeks. On physical examination, his temperature is 38.3C, pulse is 104/min, respirations are 28/min, and blood pressure is 95/60 mm Hg. A tender spleen tip is palpable. There are splinter hemorrhages under the fingernails and tender hemorrhagic nodules on the palms and soles. A heart murmur is heard on auscultation. Which of the following infectious agents is most likely to be cultured from this patient's blood? (A) Viridans streptococci (B) Trypanosoma cruzi (C) Coxsackievirus B (D) Candida albicans (E) Mycobacterium tuberculosis (F) Pseudomonas aeruginosa