Influência das condições de temperatura e pH na sensibilidade de Salmonella Typhimurium à ação de bacteriocinas associadas à EDTA

• Autor(a) principal: Prudêncio, Claúdia Vieira
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1567
• topic: Salmonella Typhimurium; Nisina; Bovicina HC5; Bactérias gram-negativas; Salmonella Typhimurium; Nisin; Bovicin HC5; Gram-negative bacteria; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS::MICROBIOLOGIA DE ALIMENTOS

Salmonella is an important pathogen in food microbiology and as well as the other Gram-negative bacteria is naturally resistant to the action of lantibiotics, such as nisin and bovicin HC5. However, the association with the EDTA is successfully employed in the sensitization of Gram-negative bacteria to the action of antimicrobial peptides, for acting in the destabilization of the outer membrane. The action of bacteriocins is influenced by several factors, such as temperature and pH, and although these environmental conditions also promote the adaptive response in microorganism, little is known about the effect on the action of bacteriocin, particularly for bovicin HC5. In this work, we evaluated the influence of environmental conditions of temperature and pH on the sensibility of Salmonella Typhimurium to the action of nisin or bovicin associated to EDTA. Nisin to exhibited bactericidal activity in broad range of temperature and pH, while bovicin HC5 acted as bacteriostatic agent in the most conditions utilized and exhibited bactericidal activity in specific environmental conditions. Moreover, was observed that cells pre-adapted in specific conditions of temperature and pH (pH 6.9 e 39.9 °C e pH 7.2 e 27.5 °C) demonstrated greater tolerance to treatment with nisin associated to EDTA. It was detected cellular modifications in this cell group, related to to cell membrane and the lipopolysaccharide layer (LPS), by Fourier transform infrared spectroscopy (FT- IR). This behavior was not evidenced with use of bovicin HC5, as well as the xcross-tolerance between these lantibiotics. These results indicate that the environmental conditions should be considered for application of nisin or bovicin HC5 associated to EDTA and the use of both lantibiotics can be an alternative for ensure safety against Salmonella Typhimurium.