Detecção de genes de virulência de Staphylococcus aureus identificados por PCR em amostras de leite de vacas com mastite clínica ou subclínica

• Ano de defesa: 2014
• Autor(a) principal: Freitas, Fernanda Antunha de
• Orientador(a): Mesquita, Albenones José de
• Banca de defesa: Mesquita, Albenones José de, Carneiro, Megmar Aparecida dos Santos, Romero, Rolando Alfredo Mazzoni
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Ciência Animal (EVZ)
• Departamento: Escola de Veterinária e Zootecnia - EVZ (RG)
• País: Brasil
• Palavras-chave em Português: Staphylococcus aureus; Mastite; PCR em tempo real; Fatores de virulência
• Palavras-chave em Inglês: Staphylococcus aureus; Mastitis; Real time PCR; Virulence factors
• Área do conhecimento CNPq: MEDICINA VETERINARIA PREVENTIVA::SAUDE ANIMAL (PROGRAMAS SANITARIOS)
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/4116

Staphylococcus aureus can produce a wide variety of virulence factors secreted or associated with bacterial wall, among them the exotoxins. The pathogenicity of S. aureus to the bovine udder is not quite clarified, but the staphylococcal exotoxins and their combinations may play a role in the pathogenic potential of the microorganism. Considering that knowing the virulence factors of S. aureus provides an important information of the establishment of effective control strategies of intramammary infections we aimed to detect the DNA of S. aureus isolates from milk of cows with clinical or subclinical mastitis and identify genes encoding bacterial exotoxins and superantigens. For this purpose, in the present study were used 55 isolates of S. aureus, obtained from milk samples from cows with clinical or subclinical mastitis. The isolates were electronically identified using the methodology described by Vitek 2® device manual. Genomic DNA extrac ted using the High Pure PCR Template Preparation Kit. The laboratory analysis for detection of species and genes encoding the exotoxins were performed at the Laboratório de Especialidades Biológicas of Centro de Pesquisa em Alimentos of Escola de Veterinária e Zootecnia da Universidade Federal de Goiás (LEB/CPA/EVZ/UFG). The gene eta was detected in 85,5% of the isolates, the pvl gene in 63,6% and the tst gene in 14,5%. The etb gene was not isolated. It was verified that the Real Time PCR technique for detection of sodA gene proved to be effective in identifying the species S. aureus, and may become an important tool in the diagnosis of the bovine mastits causing microorganisms. The isolates of S. aureus mastitis harbor genes exotoxins, such as pvl, tst and eta, which the last one may play an important role in the pathogenesis of bovine mastitis since the majority of the isolates showed to be positive for its presence.