[Active infective endocarditis remaining latent for six weeks after discontinuation of antibiotic therapy: a case report].

A 75-year-old man was treated for 4 weeks with penicillin administration for infective endocarditis in the mitral valve caused by Enterococcus faecalis. The infection recurred, so he received penicillin administration for a further 6 weeks. He remained afebrile and all laboratory examinations were within normal limits for 6 weeks after the antibiotic treatment was discontinued, but the vegetation remained large and highly mobile. Since the onset, possible embolic episodes had occurred three times. He underwent mitral valve repair with annuloplasty. Although the infection appeared to have healed by antibiotic therapy, resected tissue was strongly positive for Enterococcus faecalis. This case suggests that surgery should be aggressively considered if the vegetation does not shrink markedly.