Brucella endocarditis presenting as culture-negative infective endocarditis in a tertiary cardiac center in Saudi Arabia: A 15-year case series.

BACKGROUND: Brucella endocarditis is a life-threatening complication of brucellosis that frequently presents as culture-negative endocarditis in endemic regions, posing significant diagnostic and therapeutic challenges. METHODS: We conducted a retrospective case series of 22 patients (median age 52.5 years, 90.9% male) with confirmed Brucella endocarditis managed at a tertiary center in a brucellosis-endemic area between 2009 and 2024. RESULTS: Initial blood cultures were negative in 59% of patients, while Brucella spp. were ultimately isolated from blood or valve tissue cultures in 10 patients. Serology was positive in 20/22 (90.9%), with a median standard agglutination test (SAT) titer of 1:2560 (range 1:320-1:10240). Underlying valvular disease was universal: rheumatic (31.8%), congenital (36.4%) predominantly tetralogy of Fallot and prosthetic valves (31.8%). Echocardiography showed large, mobile vegetations (mean diameter 12 mm), abscess formation in 22.7%, and frequent multivalvular involvement. All patients received combination antimicrobial therapy (median duration 4.5 months), most commonly doxycycline, rifampicin, and an aminoglycoside. Surgical intervention was required in 72.7% (16/22), primarily valve replacement; one patient died (4.5%). Relapse occurred in 18.2% (4/22), all successfully retreated. At follow-up, serological titers declined significantly. CONCLUSIONS: Brucella endocarditis should be actively considered in patients with culture-negative endocarditis in endemic regions, particularly in those with structural or prosthetic heart disease. This case series emphasizes the importance of early recognition, multidisciplinary evaluation and individualized medical and surgical management in this complex infection.