A contribuição das bombas de efluxo QacA e Smr para a multirresistência em Staphylococcus aureus

RESUMO: O efluxo de compostos antimicrobianos é um mecanismo importante na multirresistência em bactérias. Bombas de efluxo codificadas em plasmídeos, como a QacA e a Smr, estão implicadas na susceptibilidade reduzida a biocidas, geralmente utilizados na prevenção e controlo de infecções nosocomiais, incluindo as causadas por estirpes de Staphylococcus aureus resistentes à meticilina (MRSA). Neste trabalho pretendeu-se avaliar a relevância de QacA e Smr no perfil de susceptibilidade dos isolados clínicos MRSA SM39 e SM52, que transportam os plasmídeos pSM39 e pSM52 com os determinantes qacA e smr, respectivamente. A actividade de efluxo das estirpes SM39 e SM39 curada (sem pSM39) e das estirpes SM52 e RN4220:pSM52 (estirpe susceptível RN4220 transformada com pSM52) foi caracterizada por: (1) determinação da concentração mínima inibitória (CMI) de biocidas, corantes e antibióticos, na ausência e presença dos inibidores de efluxo tioridazina, clorpromazina, verapamil e reserpina; e (2) fluorometria em tempo-real. A determinação de CMIs demonstrou que a actividade de efluxo mediada por QacA e Smr está envolvida na susceptibilidade reduzida aos biocidas e corantes testados, que incluíram o brometo de hexadeciltrimetilamónio, a cetrimida, o cloreto de benzalcónio, a berberina, o cloreto de dequalínio, a pentamidina e o brometo de etídeo. Os ensaios fluorométricos confirmaram a elevada actividade de efluxo presente nas estirpes com os genes qacA ou smr. A determinação de CMIs para antibióticos β-lactâmicos em conjunto com o teste da nitrocefina revelou a presença simultânea do gene qacA e de uma β-lactamase no plasmídeo pSM39. Este trabalho evidencia a importância das bombas de efluxo QacA e Smr na resistência a biocidas em estirpes MRSA e na sobrevivência destas estirpes em ambiente hospitalar e na comunidade, para além de destacar a questão da potencial co-resistência entre biocidas e antibióticos.--------------- ABSTRACT: Drug efflux has become an important cause of multidrug resistance (MDR) in bacteria. Plasmid-encoded MDR efflux pumps, such as QacA and Smr, are implicated in reduced susceptibility to biocides, generally used in the prevention and control of nosocomial infections, including the ones caused by methicillin-resistant Staphylococcus aureus (MRSA). In this work, we aimed to evaluate the relevance of QacA and Smr to the susceptibility profile of the clinical MRSA isolates SM39 and SM52, which harbor the plasmids pSM39 and pSM52 that carry the determinants qacA and smr, respectively. Efflux activity of strain SM39 and its plasmid-free counterpart, SM39 cured, SM52 and RN4220:pSM52 (susceptible strain RN4220 transformed with pSM52) was characterized by: (1) determination of minimum inhibitory concentration (MIC) of biocides, dyes and antibiotics, in the absence and presence of the efflux inhibitors thioridazine, chlorpromazine, verapamil and reserpine; and (2) real-time fluorometry. MIC determination showed that QacA and Smr mediated efflux was involved in the reduced susceptibility profile to the biocides and dyes tested, which included hexadecyltrymethylammonium bromide, cetrimide, benzalkonium chloride, berberine, dequalinium chloride, pentamidine and ethidium bromide. Fluorometric assays confirmed the higher efflux activity present in strains harboring qacA or smr genes. Moreover, MIC determination for β-lactam antibiotics together with the nitrocefin test confirmed the presence of a β-lactamase in the plasmid carried by SM39 strain, pSM39. This work highlights the relevance of QacA and Smr to the biocide resistance in MRSA strains, and consequently to their survival and maintenance in the hospital environment and in the community. Furthermore, the presence of a β-lactamase and qacA determinants in the the same plasmid reinforces the question of the potencial biocide/antibiotic co-resistance in MRSA strains

intervenções do EEESMO que contribuem para uma parentalidade saudável

Mestrado, Enfermagem de Saúde Infantil e Pediatria, 2015, Escola Superior de Enfermagem de LisboaEste relatório foi realizado no âmbito da unidade curricular estágio com relatório, do 5º Curso de Mestrado em Enfermagem de Saúde Materna e Obstetrícia, da Escola Superior de Enfermagem de Lisboa (ESEL), pretendeu-se refletir sobre o conjunto de competências adquiridas e desenvolvidas em contexto de bloco de partos, que visa uma prática de cuidados especializados, que contribuem para a parentalidade saudável. Procedeu-se a uma revisão sistemática da literatura, a pesquisa foi realizada recorrendo á plataforma EBSCOhost web, na base de dados da CINAHL Plus with full texto, Medline e SciELO Portugal e Brasil, tendo sido selecionados 11 artigos, de forma a dar reposta, à questão, em formato PI[C]O: “Quais as intervenções do EEESMO (I) nos cursos de preparação para a parentalidade (P) que contribuem para uma parentalidade saudável (O)?”. Desta pesquisa concluiu-se que o EEESMO, nos cursos de preparação para a parentalidade, encontra-se numa posição privilegiada para desenvolver intervenções, que visam o desenvolvimento de competências dos casais, que contribuem para uma parentalidade saudável. Sabe-se, as mulheres que fazem preparação para a parentalidade lidam melhor com a dor, havendo menos mulheres em situação de cansaço, de dor insuportável ou de pânico, assim como há menor utilização de analgésicos, conseguindo uma vivência do parto positiva, e consequentemente uma parentalidade saudável. Os estudos apresentados referem que as intervenções do EEESMO promotoras da parentalidade saudável nos cursos de CPP são a educação para a saúde direcionada para: a colaboração e o controle; relaxamento e respiração adequados; preparação física e psicológica; desmistificação de preconceitos baseados em tradições orais e escritas, mitos e ritos e transferência de informações sobre gravidez, trabalho de parto e parto, de forma a tornar a mulher “uma atriz numa peça que ela conhece perfeitamente

Biologic Interconversion of Hydrogen and Formate

"Hydrogen (H2) is one of the most promising energy vehicles in alternative to the use of fossil fuels. However, in order to use H2 as energy carrier it is necessary to find a safe, economically viable, and reasonably sized solution to store and transport it. Formate has emerged as an ideal storage compound for H2 as it is a safe compound, liquid at room temperature, which can be easily stored and transported, and furthermore it allows the sequestration of CO2 in a valuable commodity chemical. Nevertheless, for the implementation of a H2 and formate economy it is crucial to find efficient processes that can be used either for the use of formate as storage material for H2 production or for the conversion of H2 and CO2 to formate.(...)

Três décadas de pesquisa em empreendedorismo: uma revisão dos principais periódicos internacionais de empreendedorismo

A pesquisa acadêmica em empreendedorismo tem crescido substancialmente durante as últimas três décadas, em parte aplicando teorias e constructos de outras disciplinas, e em parte desenvolvendo sobre o seu próprio objeto de estudo. Neste artigo realizamos um estudo bibliométrico em oito periódicos líderes na pesquisa em empreendedorismo, para captar um panorama geral e estrutural do conhecimento acumulado. Metodologicamente, analisamos autores mais prolíficos e nacionalidades, citações e obras com maior impacto, cocitações para entender a estrutura intelectual do campo e temas pesquisados para entender o foco da pesquisa. As análises incidiram sobre uma amostra de 1.414 artigos publicados ao longo de trinta anos, de 1981 a 2010. Os resultados mostram o crescimento da pesquisa em empreendedorismo, o predomínio claro da academia Norte Americana, que a pesquisa em empreendedorismo é bastante eclética relativamente às teorias e fenômenos examinados, integrando as principais teorias de Administração, e permitem examinar a estrutura intelectual que relaciona trabalhos e teorias. Destaca-se o trabalho de Schumpeter (1934) como o mais citado e cinco principais temas que pesquisados: ‘Entrepreneurial process’, ‘Environmental and external determinants of entrepreneurship’, ‘Methods, theories and research issues’, ‘Value creation and performance’ e ‘Psychological, cognitive and individual characteristics’. Concluímos apontando áreas e tópicos que merecem a atenção de acadêmicos para pesquisa futura.info:eu-repo/semantics/publishedVersio

Evaluation of tissue and circulating mir-21 as potential biomarker of response to chemoradiotherapy in rectal cancer

This research received funding from European Structural & Investment Funds through the COMPETE Programme—Programa Operacional Regional de Lisboa—Programme Grant LISBOA-01-0145-FEDER-016405,and from National Funds through FCT—Fundação para a Ciência e a Tecnologia—Programme Grant SAICTPAC/0019/2015.Response to chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (RC) is quite variable and it is urgent to find predictive biomarkers of response. We investigated miR-21 as tissue and plasma biomarker of response to CRT in a prospective cohort of RC patients; The expression of miR-21 was analyzed in pre-and post-CRT rectal tissue and plasma in 37 patients with RC. Two groups were defined: Pathological responders (TRG 0, 1 and 2) and non-responders (TRG 3). The association between miR-21, clinical and oncological outcomes was assessed; miR-21 was upregulated in tumor tissue and we found increased odds of overexpression in pre-CRT tumor tissue (OR: 1.63; 95% CI: 0.40–6.63, p = 0.498) and pre-CRT plasma (OR: 1.79; 95% CI: 0.45–7.19, p = 0.414) of non-responders. The overall recurrence risk increased with miR-21 overexpression in pre-CRT tumor tissue (HR: 2.175, p = 0.37); Significantly higher miR-21 expression is observed in tumor tissue comparing with non-neoplastic. Increased odds of non-response is reported in patients expressing higher miR-21, although without statistical significance. This is one of the first studies on circulating miR-21 as a potential biomarker of response to CRT in RC patients.publishersversionpublishe

Evaluation of Tissue and Circulating miR-21 as Potential Biomarker of Response to Chemoradiotherapy in Rectal Cancer

Response to chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (RC) is quite variable and it is urgent to find predictive biomarkers of response. We investigated miR-21 as tissue and plasma biomarker of response to CRT in a prospective cohort of RC patients; The expression of miR-21 was analyzed in pre- and post-CRT rectal tissue and plasma in 37 patients with RC. Two groups were defined: Pathological responders (TRG 0, 1 and 2) and non-responders (TRG 3). The association between miR-21, clinical and oncological outcomes was assessed; miR-21 was upregulated in tumor tissue and we found increased odds of overexpression in pre-CRT tumor tissue (OR: 1.63; 95% CI: 0.40–6.63, p = 0.498) and pre-CRT plasma (OR: 1.79; 95% CI: 0.45–7.19, p = 0.414) of non-responders. The overall recurrence risk increased with miR-21 overexpression in pre-CRT tumor tissue (HR: 2.175, p = 0.37); Significantly higher miR-21 expression is observed in tumor tissue comparing with non-neoplastic. Increased odds of non-response is reported in patients expressing higher miR-21, although without statistical significance. This is one of the first studies on circulating miR-21 as a potential biomarker of response to CRT in RC patients.info:eu-repo/semantics/publishedVersio

Potential of miR-21 to Predict Incomplete Response to Chemoradiotherapy in Rectal Adenocarcinoma

Funding: This work has received funding from European Structural and Investment Funds through the COMPETE Programme Grant LISBOA-01-0145-FEDER-016405, from National Funds through Fundação para a Ciência e Tecnologia Programme grant SAICTPAC/0019/2015 and by a cholar from the Portuguese Society of Coloproctology as Investigation in Coloproctology Research Prize 2016–2018.Background: Patients with locally advanced rectal adenocarcinoma (LARC) are treated with neoadjuvant chemoradiotherapy (CRT). However, biomarkers for patient selection are lacking, and the association between miRNA expression and treatment response and oncological outcomes is unclear. Objectives: To investigate miRNAs as predictors of response to neoadjuvant CRT and its association with oncological outcomes. Methods: This retrospective study analyzed miRNA expression (miR-16, miR-21, miR-135b, miR-145, and miR-335) in pre- and post-chemoradiation rectal adenocarcinoma tissue and non-neoplastic mucosa in 91 patients treated with neoadjuvant CRT (50.4 Gy) and proctectomy. Two groups were defined: a pathological complete responders group (tumor regression grade—TRG 0) and a pathological incomplete responders group (TRG 1, 2, and 3). Results: miR-21 and miR-135b were upregulated in tumor tissue of incomplete responders comparing with non-neoplastic tissue (p = 0.008 and p < 0.0001, respectively). Multivariate analysis showed significant association between miR-21 in pre-CRT tumor tissue and response, with a 3.67 odds ratio (OR) of incomplete response in patients with higher miR-21 levels (p = 0.04). Although with no significance, patients treated with 5-fluorouracil (5-FU) presented reduced odds of incomplete response compared with those treated with capecitabine (OR = 0.19; 95% confidence interval (CI) 0.03–1.12, p = 0.05). Moreover, significant differences were seen in overall survival (OS) in relation to clinical TNM stage (p = 0.0004), cT (p = 0.0001), presence of distant disease (p = 0.002), mesorectal tumor deposits (p = 0.003), and tumor regression grade (p = 0.04). Conclusion: miR-21 may predict response to CRT in rectal cancer (RC).publishersversionpublishe

Potential of miR-21 to Predict Incomplete Response to Chemoradiotherapy in Rectal Adenocarcinoma

Background: Patients with locally advanced rectal adenocarcinoma (LARC) are treated with neoadjuvant chemoradiotherapy (CRT). However, biomarkers for patient selection are lacking, and the association between miRNA expression and treatment response and oncological outcomes is unclear. Objectives: To investigate miRNAs as predictors of response to neoadjuvant CRT and its association with oncological outcomes. Methods: This retrospective study analyzed miRNA expression (miR-16, miR-21, miR-135b, miR-145, and miR-335) in pre- and post-chemoradiation rectal adenocarcinoma tissue and non-neoplastic mucosa in 91 patients treated with neoadjuvant CRT (50.4 Gy) and proctectomy. Two groups were defined: a pathological complete responders group (tumor regression grade—TRG 0) and a pathological incomplete responders group (TRG 1, 2, and 3). Results: miR-21 and miR-135b were upregulated in tumor tissue of incomplete responders comparing with non-neoplastic tissue (p = 0.008 and p < 0.0001, respectively). Multivariate analysis showed significant association between miR-21 in pre-CRT tumor tissue and response, with a 3.67 odds ratio (OR) of incomplete response in patients with higher miR-21 levels (p = 0.04). Although with no significance, patients treated with 5-fluorouracil (5-FU) presented reduced odds of incomplete response compared with those treated with capecitabine (OR = 0.19; 95% confidence interval (CI) 0.03–1.12, p = 0.05). Moreover, significant differences were seen in overall survival (OS) in relation to clinical TNM stage (p = 0.0004), cT (p = 0.0001), presence of distant disease (p = 0.002), mesorectal tumor deposits (p = 0.003), and tumor regression grade (p = 0.04). Conclusion: miR-21 may predict response to CRT in rectal cancer (RC).info:eu-repo/semantics/publishedVersio

Toward the Mechanistic Understanding of Enzymatic CO2 Reduction

SFRH/BD/116515/2014 PTDC/BBB-EBB/2723/2014 UID/Multi/04378/2019 grant agreement number 810856Reducing CO2 is a challenging chemical transformation that biology solves easily, with high efficiency and specificity. In particular, formate dehydrogenases are of great interest since they reduce CO2 to formate, a valuable chemical fuel and hydrogen storage compound. The metal-dependent formate dehydrogenases of prokaryotes can show high activity for CO2 reduction. Here, we report an expression system to produce recombinant W/Sec-FdhAB from Desulfovibrio vulgaris Hildenborough fully loaded with cofactors, its catalytic characterization and crystal structures in oxidized and reduced states. The enzyme has very high activity for CO2 reduction and displays remarkable oxygen stability. The crystal structure of the formate-reduced enzyme shows Sec still coordinating the tungsten, supporting a mechanism of stable metal coordination during catalysis. Comparison of the oxidized and reduced structures shows significant changes close to the active site. The DvFdhAB is an excellent model for studying catalytic CO2 reduction and probing the mechanism of this conversion.publishersversionpublishe

Design de espaços exteriores : Concepção de parques e jartins adaptados à terceira Idade

Mestrado em Desig