Validation of the abbreviated Brucella AMOS PCR as a rapid screening method for differentiation of Brucella abortus field strain isolates and the vaccine strains, 19 and RB51.

The Brucella AMOS PCR assay was previously developed to identify and differentiate specific Brucella species. In this study, an abbreviated Brucella AMOS PCR test was evaluated to determine its accuracy in differentiating Brucella abortus into three categories: field strains, vaccine strain 19 (S19), and vaccine strain RB51/parent strain 2308 (S2308). Two hundred thirty-one isolates were identified and tested by the conventional biochemical tests and Brucella AMOS PCR. This included 120 isolates identified as B. abortus S19, 9 identified as B. abortus strain RB51, 57 identified as B. abortus biovar 1, 15 identified as B. abortus bv. 2, 1 identified as B. abortus bv. 2 (M antigen dominant), 7 identified as B. abortus bv. 4, and 22 identified as B. abortus S2308 and isolated from experimentally infected cattle. The Brucella AMOS PCR correctly identified each isolate as RB51/S2308, S19, or a field strain of Brucella.

Seminal vesiculitis and orchitis caused by Brucella abortus biovar 1 in young bison bulls from South Dakota.

Specimens of blood, lymph nodes, spleens, and genitalia were collected at slaughter from seven 3- and 4-year-old male bison that had recently become seropositive for brucellosis. The animals were from a captive herd of approximately 3,500 bison located in central South Dakota. Brucella abortus biovar 1 was isolated from 2 or more specimens from each of 6 bison. Severe necrotizing and pyogranulomatous orchitis was present in 1 testicle from 1 bull, and 4 animals had mild to marked seminal vesiculitis. Immunohistochemical staining labeled organisms in seminal vesicles and the testicle with orchitis. Ultrastructurally, intact bacilli were present in cytoplasmic vacuoles of some macrophages; other macrophages contained intracytoplasmic aggregates of calcified coccobacilli.

Identification of Brucella abortus strain 19 by decreased ability to utilize erythritol as determined by gas liquid chromatography.

A method to identify Brucella abortus strain 19 by erythritol utilization using gas liquid chromatography (GLC) was developed. A total of 69 strains of B. abortus (41 virulent field strain isolates and 28 strain 19 isolates) were tested. Following incubation of the isolate with a standard amount of erythritol, the erythritol present in the cell suspension was acetylated and measured by GLC. Field strains of B. abortus utilized an average of 90.9% of the erythritol, whereas vaccine strains utilized an average of 42.4%. This difference in erythritol utilization will allow a more rapid identification of B. abortus strain 19.