Isolamento, caracterização e uso de bacteriófagos no biocontrole de Salmonella Typhimurium

• Autor(a) principal: Albino, Luiz Augusto Aguiar
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2899
• topic: Biocontrole; Salmonella sp.; Suínos; Bacteriófagos; Biocontrol; Salmonella sp.; Pigs; Bacteriophages; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS

Brazil is the fourth producer and fifth consumer of pork meet. Your chain production is evolving to provide quality products to domestic and foreign markets. However, the presence of Salmonella in practically all stages of production constitutes a public health problem of great economic loss to the industry sector. The indiscriminate use of antibiotics has promoted several mechanisms of resistance to Salmonella, making the control and eradication of this pathogen hard. Thus, there is a need to development of therapeutic practices and bacteriophages reemerge as an alternative control. The objective of this study was isolate, characterize and test phage control of Salmonella Typhimurium in pigs. Were isolated and selected bacteriophages of six properties in eight regions of Viçosa, Teixeira and Coimbra in Minas Gerais state. The selected phages were evaluated for specificity against several strains of micro-organisms, the morphology and the activity against were used in the form of pool Salmonella Typhimurium in vitro . It was possible to isolate bacteriophages in 75% of the properties and spread after they reached score between 1010 and 1011 PFU / mL. Bacteriophages showed activity against different strains of Salmonella. Regarding morphology, all had icosahedral heads and small tails indicating that they are of the order Caudovirales and family Podoviridae. The effect of bacteriophages on the count of Salmonella in the culture medium was concentration-dependent bacteriophage used. The largest reductions of viable cells of Salmonella were approximately 2.5 log CFU / mL obtained in the cultures of bacteriophages with MOI: 10000. Although not totally eliminated, the result showed a significant reduction in counts of Salmonella Typhimurium, suggesting that bacteriophages have potential for biocontrol of the pathogen. A pool with six phage isolates was tested in pigs experimentally infected with Salmonella Typhimurium and evaluate their effectiveness in the form of biocontrol. Thirty animals were experimentally infected with 105 CFU / mL of Salmonella Typhimurium and subsequently treated with different MOIS: 0.01, 1, 100 and 10000. These animals were slaughtered and samples were collected from the fecal material of the ileum, cecum and feces to quantify the count of Salmonella using the culture medium and Rambach XLT4. The spleen, kidney, liver and mesenteric lymph node of the treatment of animals it MOI: 10000 were removed to assess the translocation of bacteriophage. Administration of Salmonella Typhimurium generated picture of salmonellosis in nine animals (30%). Rambach culture medium was more specific and XLT4 more sensitive. There was a reduction in Salmonella counts of the ileum and cecum in MOIS: 100 and 10000 but no reduction in the feces in any of the treatments. The clinical salmonellosis did not allow the translocation of bacteriophage, suggesting that treatment with bacteriophages should be in the form of preventive rather than corrective Salmonella infection. It is concluded that the methodology applied in this study proved effective in reducing Salmonella counts in experimentally infected pigs, however one must consider the need to protect against the effects of bacteriophages pH and bile salts and others, during its passage the animal's digestive system to increase its viability and efficiency in the biocontrol of Salmonella Typhimurium.