Presença de DNA de Brucella abortus em subprodutos lácteos clandestinos: diferenciação da origem da cepa em vacinal (B19) ou campo pela reação da polimerase em cadeia (PCR) / Presence of Brucella abortus DNA in clandestine dairy products: differentiation between vaccinal (B19) and field strains by polymerase chain reaction (PCR)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

A PCR assay using primers designed based on the gene that encodes a 31 KDa immunogenic protein from Brucella abortus was used in the detection of Brucella spp. in 300 samples of illegal dairy products obtained in cities of the states of São Paulo (SP) and Minas Gerais (MG), Brazil. A total of 49 samples of minas frescal cheese and 18 samples of meia-cura cheese from MG were analyzed, besides 92 samples of minas frescal cheese, 33 samples of meia-cura cheese and 108 samples of raw milk from SP. Although bacterial isolation was used as reference, Brucella spp. was not isolated from any samples in which culture was contaminated by other genera of bacteria. PCR showed that 37 samples were positive for Brucella spp.: 29/141 (20,56 %) of the minas frescal cheese samples and 8/51 (15,68%) of the meia-cura cheese samples. All positive samples for Brucella spp. were confirmed as Brucella abortus by PCR using species-specific primers. Hemi-nested PCR was used for the differentiation between B19 and field strains, based on the genetic deletion of 702 pb in the vaccinal strain. Standardization of the technique enabled the differentiation of all Brucella spp. strains, showing that 30 of them (81,08%) were B19 and 7 (18,92%) of them were Brucella abortus field strains. Estimated agreement between PCR and microbiological culture as determined by Kappa indicator was considered to be poor (K = 0) due to the absence of isolation of the microorganism.

ASSUNTO(S)

brucelose animal laticínios animal brucellosis reação em cadeia por polimerase vaccine bovine vacina polymerase chain reaction dairy factories bovinos

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