36,489 research outputs found

    Espécies prevalentes em infeções associadas a dispositivos médicos de acesso vascular

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    Central venous Catheters (CVCs) and Peripheral venous Catheters (PVCs) break the skin barriers, opening a door to microorganisms that potentially cause bloodstream infections (BSIs).This study aimed to infer about the epidemiology of species associated with the use of CVCs and the design of a protocol for the surveillance of PVC tip bacterial colonization at Centro Hospitalar do Baixo Vouga. The rolling of catheter tips was performed using the Maki technique, microorganisms were identified using MALDI-TOF MS and the antimicrobial susceptibility test by disk diffusion method was performed. The majority of patients in this study were men over 60 years old. 39% of the analysed CVC tips tested positive for the presence of microorganisms, of which most were Gram-positive bacteria and only 15% of the total isolated microorganisms were considered the source of a BSI-associated with CVC use. Of the analysed PVC tips, only a small portion had a positive result for the presence of microorganisms, with Staphylococcus epidermidis being the most frequent one. Methicillin-resistant S. epidermidis and S. aureus (MRSE/MRSA) were also observed. The presence of microorganisms even though they belong to the human skin microbiota, in catheter tips is, in itself, a risk for the development of BSIs associated with catheter use.Os cateteres venosos centrais (CVCs) e os cateteres venosos periféricos (CVPs) quebram a barreira da pele, abrindo uma porta a microrganismos potencialmente causadores de infeções da corrente sanguínea (ICS). Este estudo teve como objetivos, inferir sobre a epidemiologia de espécies associadas ao uso de CVCs e o desenho de um protocolo para a vigilância da colonização bacteriana de CVPs no Centro Hospitalar do Baixo Vouga. Foi feito o rolamento de pontas de cateter através da técnica de Maki, identificação de microrganismos através de MALDI-TOF MS e o teste de suscetibilidade a antimicrobianos pelo método de difusão em disco. A maioria dos doentes deste estudo são homens com idade superior a 60 anos. 39% das pontas de CVC analisadas, testaram positivo à presença de microrganismos, dos quais a maioria eram bactérias de Gram-positivo e apenas 15% do total de isolados foram considerados causadores de ICS associada ao uso de CVC. Das pontas de CVP analisadas apenas uma pequena porção teve um resultado positivo para a presença de microrganismos, sendo Staphylococcus epidermidis o microrganismo mais frequente. Observou-se ainda a presença de espécies de S. epidermidis e S. aureus resistentes à meticilina (MRSE/MRSA). A presença de microrganismos, ainda que pertencentes ao microbiota da pele humana, em pontas de cateter é, por si só, um risco para o desenvolvimento de ICS associadas ao uso de cateter.Mestrado em Microbiologi

    Aplicações biomédicas de materiais fotoativos à base de amido

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    The centrality that light presents in the human being’s life since antiquity to its use in industrial and biomedical applications makes it a topic of intense research. The knowledge of its properties and the way it affects the environment and living beings allows us to find new applications, namely biomedical. Photodynamic therapy is known since the end of the 1970’s as a promising approach in the treatment of neoplasia. This therapeutic approach takes advantage of light’s interaction with photosensitive compounds, named photosensitizers, which in the presence of molecular oxygen produce reactive oxygen species capable of leading tumoral cells to cellular death. From tumoral cells to microbial cells was only a step, and this photodynamic approach has proved very successful, more specifically using porphyrins as photosensitizers, in inactivating microorganisms, including microbial strains multi-resistant to conventional antimicrobial agents (e.g., antibiotics, antifungals). With the rise of microbial resistance to conventional antimicrobials and increasing emergence of chronical conditions such as diabetes and its complications, it becomes imperative to find new therapies which allow to treat and help meliorate patients’ quality of life. The goal of this study was to evaluate the possibility of using cost-friendly materials, such as starch, to support porphyrinic derivatives and in this way to produce photoactive materials with the ability to act as photosensitizers and inactivate common skin infections such as the ones incited by methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa, and which arise in diabetic ulcers, and furthermore to evaluate its ability to promote tissue regeneration. The porphyrins selected to incorporate in starch were cationic porphyrin 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TPP5F) and neutral porphyrin 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TMPyP) which were prepared and later immobilized in the starch-based materials. The photoactive films prepared by incorporation of porphyrin in starch were then tested and their antimicrobial properties evaluated in in vitro and ex vivo studies. The TMPyP incorporated starch-based film revealed promising antimicrobial activity as it was able to inactivate S.aureus (MRSA), both in vitro and ex vivo, after white light exposure with an irradiance of 50 mW cm-2 for 60 min and 24h, respectively. Using porcine skin as skin infection model, this TMPyP film revealed potential in preventing the onset of bacterial infections. To evaluate the biocompatibility and possible stimulating effects in tissue regeneration of the starch/ porphyrin films, in vitro studies were conducted in cell lines of fibroblasts (HDF) and endothelial cells (HMEC), two important components of tissue regeneration and wound healing. Four different parameters were tested: cellular viability, cellular migration, ROS formation and cellular adhesion. For that, the starch/porphyrin-based materials were applied and irradiated with a red light from a LED system with an irradiance of 5 mW cm-2 for 15 min. The films of 7.06 mm2 revealed the best results in viability and at these conditions the cells present high levels of cellular ROS. The application of light seems to have influenced all parameters except ROS formation. Low dose red-light seems to positively influence viability and wound healing in endothelial cells, revealing itself as a potential promoter of vascularization. The results obtained with the starch/porphyrin films allow for a perspective of their potential application in the treatment of diabetics’ wounds/ulcers.A centralidade que a luz apresenta na vida do ser Humano desde a antiguidade até à sua utilização em aplicações industriais e biomédicas faz com que esta continue a ser objeto de intensa investigação. O conhecimento das suas propriedades e da forma como afeta o ambiente e os seres vivos permite encontrar novas aplicações nomeadamente biomédicas. A terapia fotodinâmica é reconhecida desde finais da década de 70 como uma abordagem promissora no tratamento de neoplasias. Esta abordagem terapêutica tira partido da interação da luz com compostos fotossensíveis designados de fotosensibilizadores que na presença de oxigénio molecular produzem espécies reativas de oxigénio capaz de levar à morte celular de células tumorais. Das células tumorais às células microbianas foi um passo, e esta abordagem fotodinâmica tem sido muito bem sucedida nomeadamente utilizando porfirinas como fotosensibilizadores, na inativação de microorganismos incluindo estirpes microbianas multi-resistentes aos agentes antimicrobianos convencionais (eg. antibióticos, antifúngicos, etc). Com o aumento da resistência microbiana aos antimicrobianos convencionais e o surgimento crescente de condições crónicas como diabetes e as suas complicações, torna-se imperativo encontrar novas terapias que permitam tratar e melhorar a qualidade de vida dos pacientes. Este estudo teve como objetivo avaliar a possibilidade de utilizar materiais baratos, como seja o amido, para suportar derivados porfirínicos e desta forma produzir materiais fotoactivos com capacidade de atuar como fotosensibilizadores e inactivarem comuns infeções de pele como sejam as provocadas por Staphylococcus aureus resistente à meticilina (MRSA) e Pseudomonas aeruginosa e que surgem em úlceras de diabéticos, e mais do que isso, avaliar a sua capacidade de promoverem a regeneração de tecidos. As porfirinas selecionadas para incorporar no amido foram a porfirina catiónica 5,10,15,20-tetraquis(1- metilpiridinium-4-il)porfirina (TMPyP) e porfirina neutra 5,10,15,20- tetraquis(pentafluorofenil)porfirina (TPP5F) que foram preparadas e posteriormente imobilizadas nos materiais à base de amido. Os filmes fotoactivos preparados por incorporação de porfirina em amido, foram então testados e as suas propriedades antimicrobianas em estudos in vitro e ex vivo avaliadas. O filme à base de amido com a TMPyP incorporada revelou promissora atividade antimicrobiana sendo que conseguiu inativar a S. aureus (MRSA), tanto in vitro como ex vivo, após exposição a luz branca com uma irradiância de 50 mW cm-2 por 60 min e 24h, respetivamente. Utilizando pele de porco como um modelo de infeção de pele, este filme contendo TMPyP revelou potencial em prevenir a instalação de infeções bacterianas. Para avaliar a biocompatibilidade dos filmes de amido-porfirina preparados e possíveis efeitos estimulantes na regeneração de tecidos, foram realizados estudos in vitro em linhas celulares de fibroblastos (HDF) e células endoteliais (HMEC), dois componentes importantes da regeneração de tecido e cura de feridas. Quatro parâmetros diferentes foram testados: viabilidade celular, migração celular, formação de ROS e adesão celular. Para tal os filmes à base de amido-porfirinas foram aplicados e irradiados com luz vermelha proveniente de um sistema LED com uma irradiância de 5 mW cm-2 por 15 min. Os filmes de dimensões 7.06 mm2 revelaram os melhores resultados nos ensaios de viabilidade celular, e as células nestas condições apresentam elevada quantidade de ROS celular. A aplicação de luz parece ter influenciado todos os parâmetros exceto a formação de ROS. A luz vermelha em baixa dose parece influenciar positivamente a viabilidade e regeneração em células endoteliais, revelando-se um potencial promotor de vascularização. Os resultados obtidos com os filmes amido-porfirina permitem perspetivar a sua potencial aplicação no tratamento de feridas/úlceras de diabéticos.Mestrado em Biomedicina Molecula

    Evaluation of Patients with Spontaneous Spinal Epidural Abscess

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    Purpose: Spontaneous spinal epidural abscess (SSEA) is a rare condition. It generally affects diabetics, immunosuppressed patients, intravenous drug users, and patients with recurrent skin infections or abscesses. If untreated, mortality and morbidity rates are considerably high. The most appropriate treatment is controversial. The classical triad of SSEA consists of pain, fever, and neurological deficits. In our clinical practice, we observed that people with no underlying predisposing factors could also have SSEA, and these patients can apply to the hospital with symptoms such as weight loss, loss of appetite, and general condition disorder as well, apart from the classical triad. The aim of our study is to determine the symptoms other than the classical triad and to contribute to the early diagnosis Materials and Methods: The files of the patients who applied to our tertiary neurosurgery outpatient clinic between January 2015 and December 2018 were scanned, and patients with SSEA were determined. Demographic data of patients, presence of any additional disease, complaints at hospital admission, the time between the onset of the symptoms and diagnosis, magnetic resonance imaging findings, laboratory test results, and prognoses were noted. Results: SSEA was seen in 6 (34/100000) of the patients who applied to our outpatient clinic. The mean age was 54.67±17.06 years. 66.6% (n=4) of them were male. Patients most frequently applied with pain (66.6%), weight loss (50%), and general condition disorder (50%) symptoms. Mortality developed in 33% of the patients, while 66% of the patients recovered completely. Conclusion: The absence of the classical triad in patients with SSEA delayed diagnosis and treatment of patients. If untreated, the disease can be fatal. Early diagnosis and treatment will reduce mortality and morbidity rates

    Half-Sandwich Rhodium Complexes with Releasable N-Donor Monodentate Ligands: Solution Chemical Properties and the Possibility for Acidosis Activation

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    Cancer chemotherapeutics usually have serious side effects. Targeting the special properties of cancer and activation of the anticancer drug in the tumor microenvironment in situ may decrease the intensity of the side effects and improve the efficacy of therapy. In this study, half-sandwich Rh complexes are introduced, which may be activated at the acidic, extracellular pH of the tumor tissue. The synthesis and aqueous stability of mixed-ligand complexes with a general formula of [Rh(η5-Cp*)(N,N/O)(N)]2+/+ are reported, where (N,N/O) indicates bidentate 8-quinolate, ethylenediamine and 1,10-phenanthroline and (N) represents the releasable monodentate ligand with a nitrogen donor atom. UV-visible spectrophotometry, 1H NMR, and pH-potentiometry were used to determine the protonation constants of the monodentate ligands, the proton dissociation constants of the coordinated water molecules in the aqua complexes, and the formation constants of the mixed-ligand complexes. The obtained data were compared to those of the analogous Ru(η6-p-cymene) complexes. The developed mixed-ligand complexes were tested in drug-sensitive and resistant colon cancer cell lines (Colo205 and Colo320, respectively) and in four bacterial strains (Gram-positive and Gram-negative, drug-sensitive, and resistant) at different pH values (5–8). The mixed-ligand complexes with 1-methylimidazole displayed sufficient stability at pH 7.4, and their activation was found in cancer cells with decreasing pH; moreover, the mixed-ligand complexes demonstrated antimicrobial activity in Gram-positive and Gram-negative bacteria, including the resistant MRSA strain. This study proved the viability of incorporating releasable monodentate ligands into mixed-ligand half-sandwich complexes, which is supported by the biological assays

    Antibacterial Properties of Eucalyptus globulus Essential Oil against MRSA: A Systematic Review

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    Antimicrobial resistance is a huge threat against the public health sphere and is a major cause of global mortality and morbidity. Antibiotic misuse and overuse have led to the development of many resistant bacterial strains. One particular bacterium of concern is methicillin-resistant Staphylococcus aureus (MRSA), which is the most common resistant bacteria in humans. Antibiotic development has been unable to keep up with the rapid evolution of antibiotic-resistant organisms, and there is an urgent need to identify alternative agents to combat this problem. The purpose of this systematic review is to explore the literature on the antibacterial properties of Eucalyptus globulus essential oil against MRSA. The articles used in this review were obtained through a systematic search of the literature across four databases, with the timeline being between 2002 and 2022. Twenty studies were included in this review, which used various methods to investigate the antibacterial properties of E. globulus essential oil, alone or in combination with other agents, against MRSA. The findings suggest that E. globulus essential oil has antibacterial properties against MRSA, which can be enhanced when used in combination with other agents, such as other essential oils and antibiotics

    The antimicrobial efficacy of copper, cobalt, zinc and silver nanoparticles: alone and in combination.

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    With the advent of nanotechnology, there has been an extensive interest in the antimicrobial potential of metals. The rapid and widespread development of antimicrobial-resistant and multidrug-resistant bacteria has prompted recent research into developing novel or alternative antimicrobial agents. In this study, the antimicrobial efficacy of metallic copper, cobalt, silver and zinc nanoparticles was assessed against Escherichia coli (NCTC 10538), Staphylococcus aureus (ATCC 6538) along with three clinical isolates of Staphylococcus epidermidis (A37, A57 and A91) and three clinical isolates of Escherichiacoli (Strain 1, 2 and 3) recovered from bone marrow transplant patients and patients with cystitis respectively. Antimicrobial sensitivity assays, including agar diffusion and broth macro-dilution to determine minimum inhibitory and bactericidal concentrations (MIC/MBC) and time-kill/synergy assays, were used to assess the antimicrobial efficacy of the agents. The panel of test microorganisms, including antibiotic-resistant strains, demonstrated a broad range of sensitivity to the metals investigated. MICs of the type culture strains were in the range of 0.625 - 5.0 mg/ml. While copper and cobalt exhibited no difference in sensitivity between Gram-positive and Gram-negative microorganisms, silver and zinc showed strain specificity. A significant decrease (

    Discovery of Lactomodulin, a Unique Microbiome-Derived Peptide That Exhibits Dual Anti-Inflammatory and Antimicrobial Activity against Multidrug-Resistant Pathogens

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    The human body is a superorganism that harbors trillions of microbes, most of which inhabit the gut. To colonize our bodies, these microbes have evolved strategies to regulate the immune system and maintain intestinal immune homeostasis by secreting chemical mediators. There is much interest in deciphering these chemicals and furthering their development as novel therapeutics. In this work, we present a combined experimental and computational approach to identifying functional immunomodulatory molecules from the gut microbiome. Based on this approach, we report the discovery of lactomodulin, a unique peptide from Lactobacillus rhamnosus that exhibits dual anti-inflammatory and antibiotic activities and minimal cytotoxicity in human cell lines. Lactomodulin reduces several secreted proinflammatory cytokines, including IL-8, IL-6, IL-1β, and TNF-α. As an antibiotic, lactomodulin is effective against a range of human pathogens, and is most potent against antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). The multifunctional activity of lactomodulin affirms that the microbiome encodes evolved functional molecules with promising therapeutic potential

    Liver-dependent lung remodeling during systemic inflammation alters responses to secondary infection

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    Systemic duress, like that elicited by sepsis, burns or trauma, predisposes patients to secondary pneumonia, demanding better understanding of host pathways influencing this deleterious connection. These pre-existing circumstances are capable of triggering the hepatic acute phase response (APR), which is essential for limiting susceptibility to secondary lung infections. To identify potential mechanisms underlying protection afforded by the lung-liver axis, our studies aimed to evaluate liver-dependent lung reprogramming when a systemic inflammatory challenge precedes pneumonia. WT mice and APR-deficient littermates lacking hepatocyte STAT3 (hepSTAT3-/-), a transcription factor necessary for full APR initiation, were challenged intraperitoneally with LPS to induce endotoxemia. After 18h, pneumonia was induced by intratracheal E. coli instillation. Endotoxemia alone elicited significant transcriptional alterations in the lungs of WT and hepSTAT3-/- mice as determined by bulk RNAseq, with nearly 2,000 differentially expressed genes between genotypes. The gene signatures revealed exaggerated immune activity in the lungs of hepSTAT3-/- mice, which were compromised in their capacity to launch additional cytokine responses to secondary infection. A separate study performed with single-cell RNASeq revealed a wide range of affected lung cells in hepSTAT3-/- mice, with macrophages/monocytes, neutrophils, fibroblasts, epithelial cells, and endothelial cells all exhibiting remodeled transcriptomes in the absence of an intact liver response. Proteomics revealed substantial liver-dependent modifications in the airspaces of pneumonic mice, implicating a network of dispatched liver-derived mediators influencing lung homeostasis. Coagulation proteins, including several acute phase proteins, were prevalent among these mediators, implying a dysregulation of this immune pathway despite no detectable change in blood clotting capacity in our initial studies. These results indicate that following systemic inflammation, liver acute phase changes dramatically remodel the lungs, resulting in a modified landscape for any stimuli encountered thereafter. Based on the established vulnerability of hepSTAT3-/- mice to secondary lung infections, we believe that intact liver function is critical for maintaining the immunological responsiveness of the lungs

    Small-area heaters lyse bacteria on the chip.

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    MRSA cells were lysed with achromopeptidase enzymes and thermally deactivated in tube controls (n = 3 tubes) in a heat block or with the small-area heaters in the MD NAAT (n = 3 devices). Twenty µL of each lysate rehydrated lyophilized pad containing reagents for isothermal strand displacement amplification (iSDA), placed in a PMMA tray, heated to 50.5°C, and imaged in a plate reader in fluorescence mode in real-time. Cell suspensions heated in the lysis chamber for at least 4 minutes showed significantly higher MRSA-specific fluorescence than negative controls after 20 minutes of amplification (* p<0.00001, one-way ANOVA). Bars show mean and error bars show standard error of the mean.</p

    The phenolic constituents and antimicrobial activity of Xanthium spinosum (Asteraceae) extracts

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    Xanthium spinosum is a cosmopolitan annual herb used in traditional medicine worldwide. Although known from ethnobotanical studies, the species is scarcely investigated from the aspects of phytochemistry and biological activity. Therefore, the phenolic composition and biological activity of X. spinosum were examined. Plant specialised metabolites (phenolics) extracted from the roots, leaves and fruits with dichloromethane:methanol (1:1) were analysed by liquid chromatography mass spectrometry (LC-MS). In total 10 phenolic compounds were identified and quantified. Six compounds were common to all the extracts. Chlorogenic acid was the most abundant constituent in all the extracts (4.262 mg/g in the fruit extract, 0.820 mg/g in the leaf extract, and 0.540 mg/g in the root extract). The biological activity (antimicrobial and antibiofilm) of the extracts was tested against 12 microfungi and 12 bacterial strains by the microdilution method. All the extracts exhibited moderate antimicrobial and antibiofilm activity and inhibited the growth of most of the examined microorganisms. The obtained results indicate the potential role of the tested extracts in pharmacy and medicine
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