Culture-negative endocarditis with multifocal spread and flail mitral valve leaflet: a case report.

Introduction: Blood culture-negative infective endocarditis is the condition in which a causative organism cannot be identified after inoculation of at least three samples using standard blood-culture systems for 7 days. It has a low reported incidence of about 2.5-31%. Causes may be infectious or non-infectious; use of prior antibiotic therapy is usually the leading factor. Case presentation: The authors present a case of true culture-negative endocarditis involving the mitral valve, with multiple foci of spread including brain, spleen, liver, and Intervertebral disc, which remained persistent despite treatment with intravenous broad-spectrum antibiotics on an inpatient and outpatient basis but eventually improved after upgrading alternative broad-spectrum antibiotic for an extended duration. The patient had complications in the form of a flail mitral valve with persistent mitral regurgitation, requiring mitra-clip placement. Discussion: Positive blood culture is one of the major diagnostic criteria to establish infective endocarditis. Patients may have persistent negative cultures due to previous antibiotic use, the presence of fastidious organisms, or the use of inappropriate techniques or media. Involvement of a multidisciplinary team, use of multimodal investigations, and appropriate antibiotic stewardship are crucial. Extended duration of treatment and upgrading antibiotics can be helpful next steps in highly suspicious cases. With multifocal spread as in our case, it further becomes challenging to control and treat the infection as it is frequently connected with higher morbidity and mortality. Conclusion: Blood culture-negative endocarditis is an entity that can present with early complications. It is diagnostically and therapeutically challenging to treat such patients. Multimodal approaches for early diagnosis and appropriate treatment are crucial owing to its high morbidity and mortality.