Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/18/2003
Publication Date: N/A
Technical Abstract: During the winter of 2002-2003, 80 adult feral swine were trapped on a Brucella endemic 7,100 hectare tract of land on a peninsula between the Atlantic Ocean and the Winyah Bay in Georgetown County, South Carolina. All animals were euthanized and complete necropsies were performed. The following tissues, fluids, and swabs were harvested for bacteriological culture: liver, spleen, lung, kidney, uterus, mammary tissue, testis, seminal vesicle, bulbourethral gland, prostate, urine, blood, nasal swab, vaginal swab, and lymph nodes including prescapular, medial retropharyngeal, sternal, tracheobronchial, gastrohepatic, prefemoral, popliteal, mandibular, and parotid. All tissues were freshly frozen at -70° C. After thawing, tissues were ground in approximately 10% (w/v) sterile PBS and plated on the following media: tryptose agar with 5% bovine serum, Kudzas Morse (KM) agar, and brilliant green agar (BGA). Plates were incubated for 5-7 days at 37° C and 5% CO2. Brucella suspect colonies were picked on the basis of morphologic characteristics and typed as Brucella by a PCR assay which targeted the conserved omp 2a portion of the Brucella genome. PCR positive samples were subcultured onto KM and/or BGA agar for individual colony isolation. Individual colonies were isolated, propagated, and characterized by standard biochemical, antigenic, phage typing, and molecular techniques. Standard identification strategies included growth on selective media, urease characteristics, hydrogen sulfide production, antibiotic sensitivity, phage typing, and major antigenic characterization. Isolates were species typed using several PCR assays. A multiplex PCR assay which could differentiate Brucella abortus, Brucella abortus RB51, and Brucella abortus S19, from other Brucella species was used to screen initial subcultures and in some cases primary isolates. PCR assays against the omp 2a and omp 31 loci combined with RFLP analysis helped species type and subgroup the isolates. Select isolates were also characterized using a newly described variable number tandem repeat (VNTR) assay for Brucella which allowed the identification of genomic similarities and differences among the isolates based on the VNTR polymorphisms. Both Brucella suis and Brucella abortus were recovered, and multiple subgroups within each species were identified. The results of these studies will be presented.