The use of bacteriophages to control infectious biofilms

EMBO Conference on Viruses of Microbes III: Structure and Function - from Molecules to Communities (Programme and Abstract Book)info:eu-repo/semantics/publishedVersio

O potencial biotecnológico dos bacteriófagos na deteção e controlo de bactérias patogénicas

Os bacteriófagos (fagos) apresentam um imenso potencial biotecnológico com aplicação na saúde devido às suas características intrínsecas de reconhecimento e morte do hospedeiro que infetam (bactérias). A exploração destas características no desenvolvimento de métodos de deteção e de controlo de bactérias patogénicas é relativamente recente, embora a utilização de fagos como ferramentas de biologia molecular seja bastante antiga e a terapia fágica uma prática secular, actualmente limitada a alguns países

Phages/biofilm interaction: strategies to improve phage efficacy against infectious biofilms

The complex heterogeneous structure of biofilms confers to bacteria an important survival strategy. Biofilms are frequently involved in many chronic infections in consequence of their low susceptibility to antibiotics as well as resistance to host defences. The increasing need of novel and effective treatments to target these complex structures has led to a growing interest on bacteriophages (phages) as a strategy for biofilm control and prevention. Theoretically, the close proximity of cells within the biofilm structure could enhance phage-host interaction and facilitate phage infection. Conversely, the biofilm structure and composition as well as the physiological state of the biofilm cells may be an obstacle to phage infection. Nonetheless, phages have developed mechanisms to overcome biofilm barriers in a natural evolutionary prey-predator model. A thorough characterisation of biofilm/phage interaction and the identification of the weak aspects of biofilms and the strong features of phages are thus important to develop efficient phage-based biofilm control strategies. Phages can be used alone, as a cocktail to broaden the spectra of activity, or in combination with other antimicrobials to improve their efficacy. In this presentation studies involving the use of phages for the treatment or prevention of bacterial biofilms will be summarized, highlighting the biofilm features that can be tackled with phages or combined therapy approaches.info:eu-repo/semantics/publishedVersio

Colaboração terapêutica e expressão verbal de necessidades do cliente: um estudo comparativo de um caso de sucesso e um caso de insucesso

Dissertação de mestrado integrado em Psicologia (área de especialização em Psicologia Clínica e da Saúde)O presente estudo pretende analisar a associação entre a expressão verbal de necessidades dos clientes nos episódios de interação entre o terapeuta e o cliente referentes à colaboração terapêutica. Isto foi conseguido analisando dois casos (18 sessões) seguidos em psicoterapia de acordo com a abordagem cognitivo comportamental com diferentes resultados, um sucesso e um insucesso, considerando três fases do tratamento, inicial, intermédia e final. Para a codificação da expressão verbal de necessidades recorreu-se ao Marcador de Responsividade Terapêutica do Sistema Observacional da Responsividade Terapêutica – Expressão Verbal de Necessidades (EVN) – e ao Sistema de Codificação da Colaboração Terapêutica que permite codificar de forma sequencial os episódios interativos como de colaboração, não colaboração e de ambivalência. Ambos os sistemas se baseiam na análise do momento a momento da sessão psicoterapêutica. As análises realizadas permitiram concluir que existem associações entre os tipos de episódios interativos e a presença de EVN, entre os tipos de episódios interativos e os eixos de EVN, entre os episódios interativos, os eixos de EVN e o resultado do tratamento e entre os episódios interativos, os eixos de EVN e as fases do tratamento.The present study objective is to analyze the association between the verbal expression of needs of clients in interaction episodes between the therapist and the client linked to therapeutic collaboration. This was obtained by analyzing two psychotherapeutic cases (18 sessions) followed according an cognitive behavioral approach with different results, one with a poor outcome and one with a good outcome, taking into account three treatment stages, initial, intermediary and final. To code the verbal expression of needs it was used the Therapeutic Responsiveness Marker of the Therapeutic Responsiveness Observational System – Verbal Expression of Needs (VEN) – and the Therapeutic Collaboration Coding System that allows the sequential coding of interaction episode – collaborative, non-collaborative and ambivalent. Both systems are based on a moment by moment analysis of the therapeutic session. The analysis allowed the conclusion that there are associations between the types of interactive episodes and the presence of VEN, between the types of interactive episodes and the axis of VEN, between the types of interactive episodes, the axis of VEN and the cases outcome and between types of interactive episodes, the axis of VEN and treatment stages

The use of bacteriophages to control biofilms

Este resumo faz parte de: Book of abstracts of the Meeting of the Institute for Biotechnology and Bioengineering, 2, Braga, Portugal, 2010. A versão completa do livro de atas está disponível em: http://hdl.handle.net/1822/1096

The role of exopolymers in Sphingomonas paucimobilis attachment and biofilm formation

Exopolymers have an important role in biofilm formation, being involved in the initial adhesion events and influencing the biofilm characteristics. The results of a study with a strain of Sphingomonas paucimobilis that excretes a polysaccharide gum (gellan) has been used to exemplify the role of exopolymers in cell attachement and biofilm formation. The attachement results were interpreted throught the XDLVO theory and they revealed that exopolymers have a dual role in cell attachement by booth coating the substratum making adhesion favourable and by strengthing adeshion through the establishement of polymeric bridges. Exopolymers were also essential to the formation of Sphingomonas paucimobilis biofilms acting as scaffolds for bacterial proliferation. The physicochemical properties, the composition of the biofilm matrix and the cohesion forces within the biofilm were also conditioned by the presence of exopolymers

Bacteriophage-derived enzymes: from exploration to exploitation

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Bacteriophages are viruses infecting bacterial cells. During their replication cycle, these viruses cross the bacterial cell wall twice. Firstly, bacteriophages have to inject their genome across the cell wall to initiate infection. Secondly, they must exit the host cell at the end of the replication cycle to infect new host cells. The principal barrier to overcome is the polysaccharides that can either be extracellular (slime or capsules) or structural (peptidoglycan). For this, bacteriophages encode two specific enzymes, called depolymerases and endolysins, to degrade these polymers to enable either infection or lysis. [...]info:eu-repo/semantics/publishedVersio

Candida albicans and Candida dubliniensis: comparison of biofilm formation in terms of biomass and activity

Candida albicans and C. dubliniensis are two species responsible for oral candidiasis, especially in immunocompromised patients. Microbial infection is preceded by adherence and biofilm formation. Biofilm formation represents the most common form of C. albicans in the oral cavity and is considered to be one of the most important virulence factors. In this study, the biofilm formation ability of C. dubliniensis was compared with that of C. albicans in terms of biomass (quantified using crystal violet) and activity (assessed by formazan salts formation). Both species formed heterogeneous biofilms; however, species and strain variations were seen in the quantification of biomass and activity. There was no correlation between pseudohyphae formation and biofilm formation capability.Fundação para a Ciência e a Tecnologia (FCT) - grant BD3195/2000, project POCTI/BIO/42638/2001