[Hybrisep, a new method for the diagnosis of blood culture-negative infective endocarditis: a case report].

: Blood cultures were considered as the gold standard for the diagnosis of infective endocarditis (IE) but were frequently negative. This report describes an IE patient who successfully underwent aortic valve replacement; it discusses a new diagnostic method of blood culture-negative IE. Recently, Hybrisep (FUSO Pharmaceutical Industries, Japan), a rapid diagnostic method for bacteremia was developed using in situ hybridization, which is superior in sensitivity to conventional blood cultures. In this case, echocardiography confirmed severe aortic regurgitation and aortic valve vegetations, while serial blood cultures could not reveal any pathogenic organisms. A preoperative serum sample was found to be positive for Enterococcus faecalis by Hybrisep. Gram stain examination of the excised valves showed gram-positive cocci and therefore correlated with the finding by Hybrisep. After surgery, the patient was successfully treated with appropriate antibiotics according to these results. In summary, Hybrisep will have a promising positive impact on IE patient care.