Several Brucella species are recognized as pathogens in mammals, primarily affecting reproductive or locomotor systems.1 A newly recognized Brucella sp. closely resembling Brucella inopinata, has recently been isolated from abscesses in a big-eyed tree frog Leptopelis vermiculatus, and from the carcasses of African bullfrogs Pyxicephalus edulis.1,2 This report describes the clinicopathologic and molecular features of brucellosis due to a Brucella inopinata-like bacterium in three waxy tree frogs in a zoological collection. All cases had histologic features of abscess formation and/or sepsis. Clinical, gross, and histologic features were similar to other primary bacterial infections of amphibians, including mycobacteriosis and chlamydiosis, emphasizing the importance of culture and pathologic investigation. Brucella inopinata phenotypically resembles Ochrobactrum anthropi, necessitating molecular sequencing for differentiation. Brucella inopinata or a very closely related Brucella sp. appears to be a primary pathogen in frogs. Brucella inopinata has been cultured from humans with typical symptoms of brucellosis.1 Transmission of Brucella spp. from frogs or other animals to humans has thus far not been documented.
1. Fischer D, N Lorenz, W Heuser, P Kampfer. Abscesses associated with a Brucella inopinata-like bacterium in a big-eyed tree frog (Leptopelis vermiculatus). J Zoo Wildl Med. 2012;43:625–628.
2. Eisenberg T, H-P Hamann, U Kaim, et al. Isolation of potentially novel Brucella spp. from frogs. Appl Environ Microbiol. 2012;78:3753–3755.