Fever of Unknown Origin Due to Legionella dumoffii Bioprosthetic Aortic Valve Endocarditis

Legionella dumoffii is a rare human pathogen but has been known to cause infective endocarditis. The diagnosis is challenging as this bacterium is difficult to grow in standard culture media. We present a case of a patient with fever of unknown origin (FUO) who was diagnosed with L dumoffii bioprosthetic aortic valve endocarditis using metagenomic next-generation sequencing. After identification of this pathogen and targeted antibiotic treatment, the patient experienced complete resolution of symptoms. Legionella dumoffii infective endocarditis should be considered in patients with FUO and prosthetic heart valves.