First case of Fusobacterium necrophorum endocarditis to have presented after the 2nd decade of life.

Fusobacterium necrophorum, an obligate, anaerobic, filamentous, gram-negative rod, is thought to be a normal inhabitant of the mucous membranes in human beings. Fusobacterium species have been implicated in cases of Lemierre syndrome and other pathologic conditions. Their reported association with infective endocarditis is extremely rare. We describe the case of a previously healthy 34-year-old man who emergently presented with flu-like symptoms and dyspnea on exertion. He had recently undergone a dental procedure. Empiric antibiotic therapy was initiated. Blood cultures were positive for metronidazole-resistant F. necrophorum. A transesophageal echocardiogram revealed 2 mobile vegetations on the mitral valve. Despite the antibiotic therapy, the patient's respiratory status worsened and, after 3 weeks, he died. On the basis of the organism's pathophysiology and the patient's recent dental procedure, the oral cavity was the likely source of the bacteremia. Our patient's case underscores the importance of recognizing Fusobacterium bacteremia as a possible cause of endocarditis. To our knowledge, this is the first reported case of monomicrobial F. necrophorum endocarditis to have presented in a patient after the 2nd decade of life. In addition, it is apparently only the 4th report of F. necrophorum mitral valve endocarditis with case results derived from modern culture techniques.