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Advisor(s)
Abstract(s)
A pele é um órgão importante nos mamíferos e desempenha um papel essencial na defesa do organismo humano, sendo a sua primeira barreira face ao ambiente externo. Os principais filos que fazem parte da microbiota de uma pele saudável são: Actinobacteria (51.8%), Firmicutes (24.4%), Proteobacteria (16.5%), and Bacteroidetes (6.3%), sendo os géneros predominantes o Corynebacterium, Propionibacterium e o Staphylococcus. Quando ocorre disbiose (desequilíbrio entre a microbiota comensal e os microrganismos oportunistas), podem-se originar patologias da pele. A maioria dos distúrbios da pele, são principalmente inflamatórios e são tradicionalmente tratados com corticosteróides. No entanto, existem alguns efeitos colaterais relacionados ao seu uso, como efeitos cutâneos deletérios, anormalidades eletrolíticas, hipertensão, hiperglicemia, efeitos imunológicos e neuropsicológicos, entre outros. Uma prescrição a longo prazo também está associada à osteoporose. Na tentativa de reduzir esses efeitos colaterais, os probióticos foram sugeridos como coadjuvantes na terapia, via aplicação tópica. Em vista disso, o presente trabalho teve como objetivo realizar estudos de competição entre probióticos selecionados e bactérias patogénicas nas seguintes combinações: (Lactobacillus paracasei / Staphylococcus aureus; L. paracasei / Staphylococcus epidermidis; L. paracasei / Escherichia coli; L. paracasei / Pseudomonas aeruginosa); (Propioniferax innocua / E. coli; P. innocua / P. aeruginosa); (Bifidobacterium longum spp. infantis / S. aureus; B. longum spp. infantis / S. epidermidis; B. longum spp. infantis / E. coli; B. longum spp. infantis / P. aeruginosa). O probiótico que apresenta a melhor vantagem competitiva foi posteriormente testado em ensaios de cultura celular usando células HaCat (linha celular de queratinócitos da pele humana) para entender-se o probiótico (L. paracasei) foi capaz de impedir a adesão das bactérias patogénicas (S. aureus, S. epidermidis e P. aeruginosa). Os melhores resultados foram obtidos pela técnica de deslocamento face ao S. aureus, onde foi observada uma redução de 3.8 unidades logarítmicas. Estes resultados não coincidem com os obtidos pelos ensaios de competição de células no seu estado livre. As principais razões provavelmente são a acessibilidade das células no meio, a auto/coagregação das células e a estimulação pelo Quorum Sensing. Com o intuito de se compreender alguns dos mecanismos utilizados para impedir essa adesão, também foi realizado um ensaio de adesão das proteínas. A partir dos resultados obtidos, pode-se inferir que parte do processo de adesão implica a utilização de proteínas, embora não seja um mecanismo exclusivo.
As major organ in mammals, and first barrier of defense against external environment, the skin plays an essential role in the defense of the human organism, harboring a characteristic microflora. The most commonly found phyla of bacteria in healthy skin are Actinobacteria (51.8%), Firmicutes (24.4%), Proteobacteria (16.5%), and Bacteroidetes (6.3%) in which the most prevalent genera are Corynebacterium, Propionibacterium and Staphylococcus. Dysbiosis occurs when there is an unbalance between the commensal microbiota and opportunistic microorganisms., which can lead to skin pathologies. The majority of skin disorders, which are mainly inflammatory, are traditionally treated with corticosteroids. However, there are some side effects linked to their use such as deleterious cutaneous effects, electrolyte abnormalities, hypertension, hyperglycemia, immunologic, and neuropsychologic effects, among others. The long-term prescription is also associated with osteoporosis. In an attempt to reduce those side effects, probiotics have been suggested as co-adjuvandants in the therapy, via topical application. In this context, the present work was aimed at performing competition studies between selected probiotics and pathogenic bacteria in the following combinations: (Lactobacillus paracasei/Staphylococcus aureus; L. paracasei/Staphylococcus epidermidis; L. paracasei/Escherichia coli; L. paracasei/Pseudomonas aeruginosa); (Propioniferax innocua/E. coli; P. innocua/P. aeruginosa); (Bifidobacterium longum spp. infantis/S. aureus; B. longum spp. infantis/S. epidermidis; B. longum spp. infantis/E. coli; B. longum spp. infantis/P. aeruginosa). The probiotic presenting the best competitive advantage was then further tested in cell culture assays using HaCat cells (keratinocyte cell line from human skin) to assess the probiotic (L. paracasei) preventive role in the adhesion of the pathogenic bacteria (S. aureus, S. epidermidis and P. aeruginosa). The best results were achieved with the displacement technique towards S. aureus, in which a reduction of 3.75 logarithmic units was observed. These results did not match those obtained by the planktonic cell competition assays. The main reasons probably being cell accessibility in the media, cell (s) self / coaggregation and the empowerment by quorum sensing. In order to gain some insight on the mechanisms used to prevent this adhesion, a protein adhesion assay was also conducted. From the results obtained it can inferred that part of the adhesion process uses proteins, although not being an exclusive mechanism.
As major organ in mammals, and first barrier of defense against external environment, the skin plays an essential role in the defense of the human organism, harboring a characteristic microflora. The most commonly found phyla of bacteria in healthy skin are Actinobacteria (51.8%), Firmicutes (24.4%), Proteobacteria (16.5%), and Bacteroidetes (6.3%) in which the most prevalent genera are Corynebacterium, Propionibacterium and Staphylococcus. Dysbiosis occurs when there is an unbalance between the commensal microbiota and opportunistic microorganisms., which can lead to skin pathologies. The majority of skin disorders, which are mainly inflammatory, are traditionally treated with corticosteroids. However, there are some side effects linked to their use such as deleterious cutaneous effects, electrolyte abnormalities, hypertension, hyperglycemia, immunologic, and neuropsychologic effects, among others. The long-term prescription is also associated with osteoporosis. In an attempt to reduce those side effects, probiotics have been suggested as co-adjuvandants in the therapy, via topical application. In this context, the present work was aimed at performing competition studies between selected probiotics and pathogenic bacteria in the following combinations: (Lactobacillus paracasei/Staphylococcus aureus; L. paracasei/Staphylococcus epidermidis; L. paracasei/Escherichia coli; L. paracasei/Pseudomonas aeruginosa); (Propioniferax innocua/E. coli; P. innocua/P. aeruginosa); (Bifidobacterium longum spp. infantis/S. aureus; B. longum spp. infantis/S. epidermidis; B. longum spp. infantis/E. coli; B. longum spp. infantis/P. aeruginosa). The probiotic presenting the best competitive advantage was then further tested in cell culture assays using HaCat cells (keratinocyte cell line from human skin) to assess the probiotic (L. paracasei) preventive role in the adhesion of the pathogenic bacteria (S. aureus, S. epidermidis and P. aeruginosa). The best results were achieved with the displacement technique towards S. aureus, in which a reduction of 3.75 logarithmic units was observed. These results did not match those obtained by the planktonic cell competition assays. The main reasons probably being cell accessibility in the media, cell (s) self / coaggregation and the empowerment by quorum sensing. In order to gain some insight on the mechanisms used to prevent this adhesion, a protein adhesion assay was also conducted. From the results obtained it can inferred that part of the adhesion process uses proteins, although not being an exclusive mechanism.
Description
Keywords
Pele Células livres Adesão Patologias na pele Probióticos Skin Planktonic cells Adhesion Skin disorders Probiotics