Brucella anthropi Endocarditis: An Unusual Pathogen

Background: The genus Brucella has expanded considerably in the 21st century. With the advent of advanced phylogenetic analyses, a close genetic relationship between Brucella and Ochrobactrum has been identified, leading to reclassification of Ochrobactrum species within the genus Brucella. Among these, Brucella anthropi (formerly Ochrobactrum anthropi) is increasingly recognized as a rare cause of invasive human infection. We report a clinically significant case of B. anthropi infective endocarditis and review the available literature. Methods: We report a case of B. anthropi infective endocarditis and conducted a narrative review of the English-language medical literature through 2025. Cases were analyzed for demographics, clinical presentation, antimicrobial susceptibility, and outcomes. Results: A 75-year-old man with a prosthetic aortic valve and prior endocarditis presented with fever of unknown origin, weight loss, and prior transient ischemic attacks. Blood cultures grew B. anthropi after prolonged incubation. Transesophageal echocardiography demonstrated vegetations involving both the aortic and tricuspid valves, and the patient required targeted combination antimicrobial therapy due to persistent bacteremia. Seven additional cases of B. anthropi infective endocarditis were identified on review of the literature. Most patients had underlying valvular disease or prosthetic material. Reported lethality approached 25%. Antimicrobial susceptibility patterns were variable, underscoring the importance of targeted individualized therapy. Conclusion: Consistent with other Gram-negative bacilli, B. anthropi is a rare but established cause of acute bacterial endocarditis. Despite its rarity, it may represent an under-recognized cause of invasive disease. This case highlights the importance of prolonged culture incubation, careful microbiologic interpretation, and susceptibility-guided therapy.