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Staphylococcus argenteus is an emerging species responsible for infections comparable to those induced by Staphylococcus aureus. It has been involved in few chronic or persistent infections so far. In this study, we described a case of a persistent prosthetic-joint infection (PJI) affecting a young woman. We investigated in vitro the virulence traits of the incriminated S. argenteus strain (bone cell invasion, biofilm formation and induction of inflammation) and analyzed its genome, in comparison with two other strains of S. argenteus and two S. aureus isolates. It appeared that this S. argenteus PJI strain combined biofilm formation, osteoblast invasion and intracellular persistence abilities together with genes potentially involved in the escape of the host immune defenses, which might explain the chronicization of the infection.

This paper makes an empirical study about decision making under uncertainty among students of the Federal University of Ceará. In order to measure individual risk preferences, an elicitation technique called the Multiple Price Lists is used. Such a methodology was popularized by Holt and Laury (2002) and makes use of a list of paired lotteries, structured in such a way that the number of safe choices of the individual can be used to estimate his or her degree of risk aversion. As a result, the level of risk aversion found is higher than predicted by the theory and the hypothesis of the value scale effect as well as that of the monetary incentive effect are validated by the experiment. Thus, this work shows that there is a tendency to underestimate the willingness of individuals to take risks in hypothetical laboratory experiments, with the possibility of economic losses. Este trabalho faz um estudo empírico sobre tomada de decisão sob incerteza junto a alunos da Universidade Federal do Ceará. Para mensurar as preferências individuais de risco, utiliza-se a técnica de elicitação denominada Lista De Preços Múltiplos (Multiple Price Lists). Tal metodologia, popularizada por Holt e Laury (2002), faz uso de uma lista de loterias pareadas, estruturada de maneira que o número de escolhas seguras do indivíduo possa ser utilizado para estimar o seu grau de aversão ao risco. Como resultado, o nível de aversão ao risco encontrado é maior que o previsto pela teoria, e as hipóteses de efeito da escala de valores e efeito do incentivo monetário são validadas pelo experimento. Desse modo, este trabalho constata uma tendência de subestimação na disposição dos indivíduos em assumir risco em experimentos hipotéticos de laboratório, com possibilidade de prejuízos econômicos. Este trabajo hace un estudio empírico sobre toma de decisión bajo incertidumbre junto a alumnos de la Universidad Federal de Ceará. Para medir las preferencias individuales de riesgo, se utiliza la técnica de selección denominada Lista de Precios Múltiples (Multiple Price Listas). Esta metodología fue popularizada por Holt y Laury (2002) y hace uso de una lista de loterías pareadas, estructurada de manera que el número de opciones seguras del individuo pueda ser utilizado para estimar su grado de aversión al riesgo. Como resultado, el nivel de aversión al riesgo encontrado es mayor que el previsto por la teoría, y las hipótesis de efecto de la escala de valores y efecto del incentivo monetario son validadas por el experimento. De ese modo, este trabajo constata una tendencia a la subestimación en la disposición de los individuos a asumir riesgo en experimentos hipotéticos de laboratorio, con posibilidad de pérdidas económicas.

International audience; Staphylococcus pseudintermedius is responsible for severe and necrotizing infections in humans and dogs. Contrary to S. aureus, the pathophysiological mechanisms involved in this virulence are incompletely understood. We previously showed the intracellular cytotoxicity induced after internalization of S. pseudintermedius. Herein, we aimed to identify the virulence factors responsible for this cytotoxic activity. After addition of filtered S. pseudintermedius supernatants in culture cell media, MG63 cells, used as representative of non-professional phagocytic cells (NPPc), released a high level of LDH, indicating that the cytotoxicity was mainly mediated by secreted factors. Accordingly, we focused our attention on S. pseudintermedius toxins. In silico analysis found the presence of two PSMs (δ-toxin and PSM\varepsilon) as well as Luk-I leukotoxin, the presence of which was confirmed by PCR in all clinical strains tested (n = 17). Recombinant Luk-I leukotoxin had no cytotoxic activity on NPPc but the ectopic expression of the CXCR2 receptor in U937 cells conferred cytotoxity to Luk-I. This is in agreement with the lack of Luk-I effect on NPPc and the previous report of Luk-I cytoxic activity on immune cells. Contrary to Luk-I, synthetic δ-toxin and PSM\varepsilon had a strong cytotoxic activity on NPPc. The secretion of δ-toxin and PSM\varepsilon at cytotoxic concentrations by S. pseudintermedius in culture supernatant was confirmed by HPLC-MS. In addition, the supplementation of such supernatants with human serum, known to inhibit PSM, induced a complete abolition of cytotoxicity which indicates that PSMs are the key players in the cytotoxic phenotype of NPPc. The results suggest that the severity of S. pseudintermedius infections is, at least in part, explained by a combined action of Luk-I that specifically targets immune cells expressing the CXCR2 receptor, and PSMs that disrupt cell membranes whatever the cell types. The present study strengthens the key role of PSMs in virulence of the different species belonging to Staphylococcus genus.

International audience; Multiresistant Staphylococcus capitis pulsotype NRCS-A has been reported to be a major pathogen causing nosocomial bacteremia in preterm infants. We report that the NRCS-A strain CR01 harbors a novel 60.9-kb composite staphylococcal cassette chromosome mec (SCCmec) element, composed of an SCCmec with strong homologies to Staphylococcus aureus ST398 SCCmec and of an SCCcad/ars/cop harboring resistance genes for cadmium, arsenic, and copper. Whole-genome-based comparisons of published S. capitis strains suggest that strain CR01 acquired the two elements independently.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2020-09-24T21:13:47Z No. of bitstreams: 1 Aunia Heyde Candy Dantas da Silva.pdf: 4350210 bytes, checksum: b201926b866bd623197d349f23b9f26a (MD5) Made available in DSpace on 2020-09-24T21:13:47Z (GMT). No. of bitstreams: 1 Aunia Heyde Candy Dantas da Silva.pdf: 4350210 bytes, checksum: b201926b866bd623197d349f23b9f26a (MD5) Previous issue date: 2019-07-05 This master's deegre dissertation mainly aims in understand the social mediations before the interactions of the children with their peers and with the teacher of the Childhood Education during the use of the Alphabet Educational Table by Positivo, in the context of a municipal nursery of Recife-PE. It is located in an interdisciplinary field of study on the use of a digital artifact used in school contexts of Childhood Education in Recife-PE, the Alphabet Educational Table by Positivo. We start from the ideas of Sociology of Childhood, represented by Corsaro, Sarmento and Marchi, an approach that allows us to understand contemporary children as social agents in the face of new technologies. Complementing sociological studies, the research is anchored in Vygotsky's historical-cultural theory, considering the individual as a subject of social action, and highlighting the function of the instruments in psychic and social development; Leontiev's Theory of Activity, updated in the Engeström pyramid, as a way of understanding the actions of the individual in the complex mediated social network. This is a predominantly qualitative ethnographic case study, carried out in three moments: 1) Macro-analytical moment, with data constructed from information available on the official website of the city of Recife and the website of the Positivo company, creator of the analyzed technology; 2) Institutional-analytical moment, with observations, semi-structured interview with school coordination, which aims to characterize the ways of using digital technologies in their space; 2.2) Time of analysis of the interactions, in which observations will be made, the semi-structured interviews and videographies of social practices with the artifact in focus in the nursery and of specific situations of children in social mediations with their peers and with adults in the institutional experiences of use of the technologies. The data will be investigated through Content Analysis at moment 1 and by Interactive Analysis at moment 2 and 2.2. The results indicate that macro and micro aspects mediate the use of ICTs by children in their peers in teaching situations in Childhood Education, that is, both children in their peers and adults in the relational process act in a mediatory way in the process of using a ICT, as well as macro aspects such as public policies of a city. Esta dissertação de mestrado tem como objetivo principal compreender as mediações sociais diante das interações das crianças com seus pares e com a professora da Educação Infantil durante o uso da Mesa Educacional Alfabeto Positivo, no contexto de uma creche municipal do Recife - PE. Situa-se em um campo interdisciplinar de estudos sobre o uso de um artefato digital utilizado em contextos escolares de Educação Infantil em Recife-PE, a Mesa Educacional Alfabeto Positivo. Parte-se das ideias da Sociologia da Infância, representada por Corsaro, Sarmento e Marchi, abordagem que nos permite entender a criança contemporânea como agente social diante das novas tecnologias. Complementar aos estudos sociológicos, a pesquisa ancora-se na teoria histórico-cultural de Vygotsky, por considerar o indivíduo como um sujeito de ação social, e destacar a função dos instrumentos no desenvolvimento psíquico e social; a Teoria da atividade de Leontiev, atualizada na pirâmide de Engeström, como forma de entender as ações do indivíduo na complexa rede social mediada. Trata-se de um estudo de caso predominantemente qualitativo de cunho etnográfico, realizado em três momentos: 1) Momento macro-analítico, com dados construídos a partir de informações disponibilizadas no site oficial da prefeitura do Recife e site da empresa Positivo, criadora da tecnologia analisada; 2) Momento institucional-analítico, com observações, entrevista semi-estruturada com a coordenação escolar, que tem como objetivo caracterizar os modos de uso de tecnologias digitais em seu espaço; 2.2) Interacional-analítico, momento de análise das interações, em que foram realizadas observações, entrevistas semi-estruturadas e videografias das práticas sociais com o artefato em focoe de situações específicas de crianças em mediações sociais com seus pares e com adultos nas vivências de utilização de tecnologias, na creche. Os dados foram investigados por meio da Análise de Conteúdo no momento 1 e por Análise Interacional nos momentos 2 e 2.2. Os resultados indicam que aspectos macros e micros medeiam o uso de TICs por crianças em seus pares na Educação Infantil, ou seja, tanto crianças como adultos do processo relacional agem de forma mediadora durante o uso de uma TIC, assim como são significados mediadores os aspectos macros, como políticas públicas de um município.