Isolamento e caracterização de bacteriófagos líticos de bactérias patogênicas associadas com mastite bovina

• Ano de defesa: 2010
• Autor(a) principal: Pereira, Angelo Liparini
• Orientador(a): Paula, Sérgio Oliveira de
• Banca de defesa: Araujo, Elza Fernandes de , Faria, Bolivar Nóbrega de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Biologia Celular e Estrutural
• Departamento: Análises quantitativas e moleculares do Genoma; Biologia das células e dos tecidos
• País: BR
• Palavras-chave em Português: Bacteriófagos; Mastite bovina; Fagoterapia
• Palavras-chave em Inglês: Bacteriophages; Bovine mastitis; Phage therapy
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL
• Link de acesso: http://locus.ufv.br/handle/123456789/242

Bovine mastitis is the main disease affecting the herds of dairy cattle in Brazil and the world, accounting for huge losses. Several microorganisms are causing the disease, such as Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus epidermidis, Corynebacterium bovis, Corynebacterium pyogenes and Candida albicans. Of all these microorganisms S. aureus is the most prevalent. Despite antibiotic therapy is still the most widely used procedure in the treatment of bovine mastitis, we have sought alternative means of treatment due to the growing concern about the presence of antibiotic residues in milk and selection of resistant bacterial strains. The residues of antibiotics also interfere with the production of derivatives, often making it impossible to produce them. They cause public health risks and there are reports of hypersensitivity reactions after drinking milk with the presence of penicillin. The use of bacteriophages as a tool in actual control of pathogens is an alternative treatment. Therefore, this work examined the prevalence of bovine mastitis in the region of Zona da Mata Mineira, which showed a percentage of 19.19%. We performed the isolation and identification of bacteria from mastitis milk. It can be noticed that the bacteria of the genus Staphylococcus were the most prevalent, accounting for 77.22% of isolates. Some strains were tested with antibiotic, to investigate the susceptibility of these bacteria to certain antibiotics. It was found that 65% and 60% of Staphylococcus aureus strains tested were resistant to penincilina and ampicillin, respectively. Were isolated 10 bacteriophages able to infect S. aureus. These phages were evaluated for their lytic potential, its specificity and its thermostability. Furthermore, we described the characteristics of these phages on the type of genetic material, the size of genome and protein profile they present. All phage isolates showed very similar protein profile with a DNA genome of approximately 175 kb. By electron microscopy, it was found that phages were caudate, belonging to the Myoviridae family.