Avaliação de sequências alvo e PCR em diferentes etapas da metodologia convencional para detecção de Salmonella spp. em carne bovina artificialmente contaminada

• Ano de defesa: 2012
• Autor(a) principal: Almeida, Michelle Vieira de
• Orientador(a): Nero, Luís Augusto
• Banca de defesa: Bersot, Luciano dos Santos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Medicina Veterinária
• Departamento: Biotecnologia, diagnóstico e controle de doenças; Epidemiologia e controle de qualidade de prod. de
• País: BR
• Palavras-chave em Português: Salmonella; Carne bovina; PCR
• Palavras-chave em Inglês: Salmonella; Beef; PCR
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::INSPECAO DE PRODUTOS DE ORIGEM ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/5121

Salmonella spp. are a major cause of foodborne disease worldwide and are associated with the ingestion of contaminated animal origin food, such as meat, eggs and milk. Traditional methods for detection of Salmonella spp. are laborious and require several days to obtain results; because of this, the development and evaluation of methodologies that are more sensitive, specific and rapid, such as the Polymerase Chain Reaction (PCR), are needed. In this study, we evaluated six primer pairs for Salmonella detection by PCR: 139/141 (targeting a specific region of invA gene), OMPCF/OMPCR and S18/S19 (ompC gene), LHNS-531/RHNS-682 (hns gene), ST11/ST15 (chromosomal random fragment) and SIFBF/SIFBR (sifB gene). Several isolates of Salmonella spp. and other microorganisms were used for determining the efficiency of the primers. SIFBF/SIFBR primer pair presented the best performance because it amplified the target region in all Salmonella isolates, and didn't yield any false positives or nonspecific bands. Considering these results, SIFBF and SIFBR primers were selected and used to develop a PCR assay for Salmonella spp. detection at different enrichment steps of the conve ntional detection method, in beef samples artificially inoculated with this pathogen at approximate concentrations of 101, 102 and 103 CFU/25 g. Although it was not possible to detect Salmonella spp. in the samples before enrichment, the protocol was capable of detecting the pathogen in all enrichment steps of the conventional methodology: Buffered Peptone Water after 18 h incubation, Rappaport-Vassiliadis Soya Broth and Müller-Kauffmann Tetrathionate Novobiocin Broth. These results indicate that the proposed protocol was viable to detect Salmonella spp. in beef in intermediate stages of the conventional isolation protocol, substantially reducing the time required to obtain final results. Additional studies are necessary to evaluate the proposed protocol in meat naturally contaminated with Salmonella spp.