Infection Caused by Brucella intermedia Isolated from a Case of Chronic Sinusitis with a Nasal Abscess in South Korea

Brucella intermedia is a motile, non-spore-forming, Gram-negative coccobacillus that is catalase-and oxidase-positive and belongs to the genus Brucella.It is considered a low-virulence organism widely distributed in the environment that can cause opportunistic infections.We report a case of a 65-year-old immunocompetent woman with a history of hypertension who presented with a headache and chronic postnasal drip.Paranasal sinus computed tomography revealed a right nasal abscess with chronic sinusitis, and endoscopic sinus surgery was performed.The organism was isolated from the abscess specimen and showed growth on blood agar, chocolate agar, and MacConkey agar after 48 hours of incubation.Identification was achieved using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing.This is the first reported case of B. intermedia infection in Korea and the first case worldwide identified from sinusitis.Because B. intermedia may be misidentified as B. anthropi or other Brucella species in clinical laboratories, exhibits multidrug resistance, and may cause severe infection in immunocompromised patients, accurate species identification using phenotypic methods in combination with MALDI-TOF MS and molecular diagnostic techniques is recommended.