Characteristics of a Brucella species from a bottlenose dolphin (Tursiops truncatus

Abstract

Abstract. A culture isolated from an aborted fetus of a bottlenose dolphin (Tursiops truncatus) was characterized. The isolate was a gram-negative coccobacillus, and the colonial morphology was typical of a smooth Brucella. The isolate was positive for catalase, oxidase, nitrate reduction, and urease. Hydrogen sulfide was not produced. It grew in air at 37 C but required 72 hours for good growth. There was growth on media containing basic fuchsin, thionin, thionin blue, penicillin, and erythritol. The M antigen was dominant, and the isolate was lysed by 4 of 10 brucellaphages tested. The oxidative metabolic profile of the isolate was similar to that for B. abortus but differed in utilization of L-asparagine, L-glutamic acid, and DL-citrulline. Whole-cell lysates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein profiles were markedly different from the protein profiles of reference strains of Brucella species. Biochemical and oxidative metabolism profiles indicated that the isolate belongs in the genus Brucella but did not match the profiles of any established species or biovars. This isolate may be an atypical strain of a recognized Brucella species or a new biovar or species of Brucella. Brucella species have been isolated from numerous animal species, including cattle, swine, goats, sheep, dogs, bison, and elk. 7,22 These bacteria cause abortion in the majority of infected hosts. There are no reports of Brucella infection in marine mammals. A bacterium was isolated from an aborted fetus of a bottlenose dolphin (Tursiops truncatus) at the Balboa Hospital, San Diego, California. The isolate was tentatively identified as a Brucella species and submitted for identification to the National Veterinary Services Laboratories (NVSL), Ames, Iowa. This report describes the characterization of this isolate using tests recommended for identification of species and biovars of the genus Brucella