RESUMO
Bacteriocins produced by lactic acid bacteria are proteinaceous antibacterial metabolites that normally exhibit bactericidal or bacteriostatic activity against genetically closely related bacteria. In this work, the bacteriocinogenic potential of Pediococcus pentosaceus strain ST58, isolated from oral cavity of a healthy volunteer was evaluated. To better understand the biological role of this strain, its technological and safety traits were deeply investigated through a combined approach considering physiological, metabolomic and genomic properties. Three out of 14 colonies generating inhibition zones were confirmed to be bacteriocin producers and, according to repPCR and RAPD-PCR, differentiation assays, and 16S rRNA sequencing it was confirmed to be replicates of the same strain, identified as P. pentosaceus, named ST58. Based on multiple isolation of the same strain (P. pentosaceus ST58) over the 26 weeks in screening process for the potential bacteriocinogenic strains from the oral cavity of the same volunteer, strain ST58 can be considered a persistent component of oral cavity microbiota. Genomic analysis of P. pentosaceus ST58 revealed the presence of operons encoding for bacteriocins pediocin PA-1 and penocin A. The produced bacteriocin(s) inhibited the growth of Listeria monocytogenes, Enterococcus spp. and some Lactobacillus spp. used to determine the activity spectrum. The highest levels of production (6400 AU/ml) were recorded against L. monocytogenes strains after 24 h of incubation and the antimicrobial activity was inhibited after treatment of the cell-free supernatants with proteolytic enzymes. Noteworthy, P. pentosaceus ST58 also presented antifungal activity and key metabolites potentially involved in these properties were identified. Overall, this strain can be of great biotechnological interest towards the development of effective bio-preservation cultures as well as potential health promoting microbes.
Assuntos
Bacteriocinas , Listeria monocytogenes , Probióticos , Humanos , Pediococcus pentosaceus/genética , Pediococcus pentosaceus/metabolismo , Técnica de Amplificação ao Acaso de DNA Polimórfico , RNA Ribossômico 16S/genética , Pediococcus/genética , Pediococcus/metabolismo , Bacteriocinas/genética , Bacteriocinas/farmacologia , Antibacterianos/farmacologia , GenômicaRESUMO
Objetivou-se avaliar a influência da cloração da água utilizada em salas de ordenha, assim como do manejo e da infraestrutura da ordenha, sobre a qualidade microbiológica da água e do leite. Foi instalado um equipamento para cloração de água, por duas semanas, na caixa de água de 20 propriedades leiteiras. Foram coletadas amostras de água e leite ao primeiro dia (sem cloro: controle), no sétimo e 14° dias (com cloro) e no 21º dia após a desinstalação dos cloradores (sem cloro: controle). Foram realizadas análises microbiológicas da água e do leite (contagem de células somáticas do leite, bactérias psicotróficas, mesófilas e coliformes totais), análises físico-químicas da água (pH, dureza e matéria orgânica), e aplicou-se um questionário estruturado aos produtores visando conhecer as técnicas de manejo de ordenha adotadas na propriedade. O uso de cloração na água melhorou (P<0,0001) a qualidade microbiológica da água, porém não afetou a qualidade microbiológica do leite (P>0,05). Práticas adequadas de manejo e higiene de ordenha e adequada estrutura para a ordenha estão relacionadas a baixas contagens de microrganismos no leite. Conclui-se que a cloração melhora a qualidade microbiológica da água, sem afetar a qualidade microbiológica do leite, a qual é melhorada pela adoção de boas práticas de ordenha e adequada infraestrutura.(AU)
The aim was to evaluate the influence of the use of sanitizing the water used on dairy farms, the management and the infrastructure on the dairy farm on the microbiological quality of water and milk. It was installed an equipment to chlorinate the water for a period of two weeks, in the water box of 20 dairy farms. In each dairy farm, water and milk samples were collected, being the first day (without chlorine: control), in the 7th and 14th day (chlorine), and 21 days after uninstalling the chlorinators (Chlorine-free: control). Microbiological analysis of water and milk (Somatic cell counts of milk, psychrotrophic bacteria, mesophilic and total coliforms) and physicochemical analysis of water were performed and a survey was applied to the farmers. The use of chlorine tablets in water improved (P<0.0001) the microbiological quality of water, but did not affect the microbiological quality of the milk (P>0.05). Management practices, hygiene and the structure of dairy farms are related to low microorganism counts in milk. In conclusion, chlorination of water improves the microbiological quality of water without affecting the microbiological quality of milk, which is improved by the adoption of good milking practices and adequate infrastructure.(AU)
