[Evaluation of 2 hemoculture media for the isolation of Brucella spp.]]

The diagnostic efficiency of two hemoculture media for the detection of different species of Brucella strains was evaluated. Strains of Brucella melitensis, Brucella suis, Brucella abortus, Brucella ovis, and Brucella abortus S19 were used. Each strain was diluted in phosphate buffer saline (PBS) to obtain a concentration of 10(5) colony forming units/ml (CFU/ml). Blood from goats, pigs, cattle, and sheep was mixed with the bacterial suspension to obtain a final concentration minor or equal to 10(3) CFU/ml. These blood samples were inoculated into the following media: (i) Hemobrucella (HB), (ii) Tryptose citrated broth 2% (CTB), and (iii) Controls without blood for B. melitensis and B.suis. Subculture in dishes and CFU/ml counts were made at the 1st, 3rd, 8th, 10th, 20th, and 30th post-inoculation (PI) day. Best results were obtained in the HB medium for all strains, except for B. suis, which due to the presence of a contaminant did not reach its maximum development in this medium. All strains were recovered from both media at 24 h PI, except B. ovis that was isolated from HB at 72 h PI and was not recovered from CTB. All strains remained viable for a shorter period in CTB. Under the proposed experimental conditions the HB medium was more sensitive than CTB. Future experiments should evaluate the utility of this commercial medium in clinical cases of animal brucellosis.