Detection of Brucella ovis in ovine from Paraíba State, in the Northeast region of Brazil

To determine the presence of Brucella ovis in ovine from Paraíba State, in the Northeast region of Brazil, 80 animals slaughtered in the public slaughterhouse of Patos city were used. Before slaughter, blood samples were collected by jugular venopuncture from each animal, and after slaughter, testicles, epidydimus and uterus were aseptically collected. For the serological diagnosis of B. ovis and B. abortus infections, the agar gel immunodiffusion (AGID) and Rose Bengal (RBT) tests were carried out, respectively. In addition, microbiological culture and polymerase chain reaction (PCR) were performed on testicle, epidydimus and uterus samples. Six animals (7.5%) tested positive for the presence of B. ovis antibodies and all animals tested negative for the presence of B. abortus antibodies. One AGID-positive animal tested positive at uterine swab culture. PCR was able to amplify DNA of Brucella spp. from the pool of testicle, epidydimus and uterus samples from AGID-positive animals. This is the first report of isolation and detection of B. ovis DNA by PCR in ovine from the Northeast region of Brazil.

Detection of Brucella abortus DNA in illegal cheese from São Paulo and Minas Gerais and differentiation of B19 vaccinal strain by means of the polymerase chain reaction (PCR)

A total of 192 samples of illegal cheese from different regions of the states of São Paulo and Minas Gerais, Brazil, were analyzed for the isolation and detection of Brucella spp. DNA by means of microbiological culture and polymerase chain reaction (PCR), respectively. Samples that yielded positive results were submitted to the analysis of the occurrence of Brucella abortus (biovars 1, 2 e 4), as well as to the differentiation of DNA in B19 vaccinal strain or Brucella abortus field strain using PCR. Although the microorganism was not isolated from any sample, PCR detected 37 positive samples (19.27%) using genus-specific primers. From these, all (100%) were Brucella abortus. Differentiation of the strain showed that 30/37 samples (81.08%) were vaccinal strain B19 and seven (18.92%) were Brucella abortus field strains. Results showed that diagnostic sensitivity of PCR was greater than that of microbiological culture. The standardization of the reaction for the differentiation of vaccinal and field strains enabled the analysis of all samples positive for Brucella abortus. It is, therefore, a reliable method, also applicable to natural infections caused by the microrganism.

Foram analisadas 192 amostras de queijo clandestinas provenientes de várias regiões do Estado de São Paulo e Minas Gerais, Brasil, para isolamento e detecção de DNA de Brucella spp. através das técnicas de cultivo microbiológico e reação da polimerase em cadeia (PCR), respectivamente. Para as amostras positivas foi pesquisada a ocorrência da espécie Brucella abortus (biovares 1, 2 e 4), além da diferenciação do DNA em cepa vacinal B19 ou de campo por PCR. Não foi possível isolar o microrganismo de nenhuma amostra, porém, na PCR, 37 amostras (19,27%) foram positivas na reação com primers gênero específicos e destas, todas (100%) foram comprovadas como sendo Brucella abortus. A diferenciação da cepa revelou que 30/37 amostras (81,08%) eram cepa vacinal B19 e sete (18,92%) eram cepas de Brucella abortus de campo. Os resultados mostraram uma maior sensibilidade diagnóstica da PCR em relação ao cultivo microbiológico, e a padronização da reação de diferenciação da cepa em vacinal ou campo permitiu que todas as amostras positivas para Brucella abortus fossem analisadas, sendo uma metodologia confiável e aplicável a infecções naturais pelo microrganismo.