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1.
JMIR Res Protoc ; 12: e37727, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37145845

RESUMO

BACKGROUND: Lack of physical activity is a common issue with detrimental consequences for the health of people with severe mental illness (SMI). Existing physical activity interventions show suboptimal effects as they require substantial cognitive skills, including goal setting and writing, whereas cognitive deficits are common in this population. To bolster the effectiveness of physical activity interventions, self-control training (SCT), in which users practice the ability to override unwanted thoughts and behaviors, can be used in addition. Recent research has demonstrated the initial effectiveness of a mobile SCT app, but this has not been studied in psychiatric clinical practice. OBJECTIVE: This study aims to evaluate to what extent adding a mobile SCT app designed for and with people with SMI to a mobile lifestyle intervention aimed at increasing physical activity increases physical activity and self-control levels. METHODS: A mixed methods approach incorporating 2 single-case experimental designs (SCEDs) and qualitative interviews was used to evaluate and optimize SCT. Overall, 12 participants with SMI will be recruited from 2 organizations offering outpatient and inpatient care to people with SMI. Each experiment will include 6 patients. SCED I is a concurrent multiple-baseline design across participants that explores initial effectiveness and optimal intervention duration. Using accelerometry and experience sampling questionnaires, participants' physical activity and self-control will be monitored for ≥5 days from baseline, followed by the sequential introduction of Google Fit, the physical activity intervention, for 7 days and the addition of SCIPP: Self-Control Intervention App for 28 days. SCED II is an introduction/withdrawal design in which optimized SCT will be introduced and withdrawn to validate the findings from SCED I. In both experiments, the daily average of total activity counts per hour and the state level of self-control will serve as the primary and secondary outcome measures. Data will be analyzed using visual analysis and piecewise linear regression models. RESULTS: The study was designated as not subject to the Dutch Medical Research Involving Human Subjects Act by the Medical Research Ethical Committee Oost-Nederland and approved by the Ethics Committee/domain Humanities and Social Sciences of the Faculty of Behavioural, Management, and Social Sciences at the University of Twente. Participant recruitment started in January 2022, and we expect to publish the results in early 2023. CONCLUSIONS: The mobile SCT app is expected to be feasible and effective. It is self-paced and scalable and can increase patient motivation, making it a suitable intervention for people with SMI. SCED is a relatively novel yet promising method for gaining insights into whether and how mobile apps work that can handle heterogeneous samples and makes it possible to involve a diverse population with SMI without having to include a large number of participants. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/37727.

2.
Ann Surg ; 278(3): e440-e446, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36727747

RESUMO

OBJECTIVE: The aim of this study was to determine if prophylactic mesh placement is an effective, safe, and cost-effective procedure to prevent parastomal hernia (PSH) formation in the long term. BACKGROUND: A PSH is the most frequent complication after stoma formation. Prophylactic placement of a mesh has been suggested to prevent PSH, but long-term evidence to support this approach is scarce. METHODS: In this multicentre superiority trial patients undergoing the formation of a permanent colostomy were randomly assigned to either retromuscular polypropylene mesh reinforcement or conventional colostomy formation. Primary endpoint was the incidence of a PSH after 5 years. Secondary endpoints were morbidity, mortality, quality of life, and cost-effectiveness. RESULTS: A total of 150 patients were randomly assigned to the mesh group (n = 72) or nonmesh group (n = 78). For the long-term follow-up, 113 patients were analyzed, and 37 patients were lost to follow-up. After a median follow-up of 60 months (interquartile range: 48.6-64.4), 49 patients developed a PSH, 20 (27.8%) in the mesh group and 29 (37.2%) in the nonmesh group ( P = 0.22; RD: -9.4%; 95% CI: -24, 5.5). The cost related to the meshing strategy was € 2.239 lower than the nonmesh strategy (95% CI: 491.18, 3985.49), and quality-adjusted life years did not differ significantly between groups ( P = 0.959; 95% CI: -0.066, 0.070). CONCLUSIONS: Prophylactic mesh placement during the formation of an end-colostomy is a safe procedure but does not reduce the incidence of PSH after 5 years of follow-up. It does, however, delay the onset of PSH without a significant difference in morbidity, mortality, or quality of life, and seems to be cost-effective.


Assuntos
Hérnia Ventral , Hérnia Incisional , Estomas Cirúrgicos , Humanos , Colostomia/métodos , Telas Cirúrgicas/efeitos adversos , Hérnia Ventral/epidemiologia , Qualidade de Vida , Hérnia Incisional/complicações
3.
J Med Internet Res ; 24(3): e33531, 2022 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-35275082

RESUMO

BACKGROUND: For eHealth technologies in general and audit and feedback (AF) systems specifically, integrating interdisciplinary theoretical underpinnings is essential, as it increases the likelihood of achieving desired outcomes by ensuring a fit among eHealth technology, stakeholders, and their context. In addition, reporting on the development and implementation process of AF systems, including substantiations of choices, enables the identification of best practices and accumulation of knowledge across studies but is often not elaborated on in publications. OBJECTIVE: This scoping review aims to provide insights into the development and implementation strategies for AF systems for a real-world problem that threatens modern health care-antimicrobial resistance-and provide an interdisciplinary conceptual framework that can serve as a checklist and guidance for making informed choices in the development and implementation of future AF systems. METHODS: A scoping review was conducted by querying PubMed, Scopus, Web of Science, IEEE Xplore Digital Library, and Embase (≥2010) for studies describing either the development or implementation process, or both, of an AF system for antimicrobial resistance or infections in hospitals. Studies reporting only on effectiveness or impact were excluded. A total of 3 independent reviewers performed the study selection, and 2 reviewers constructed the conceptual framework through the axial and selective coding of often-used theories, models, and frameworks (TMFs) from the literature on AF and eHealth development and implementation. Subsequently, the conceptual framework was used for the systematic extraction and interpretation of the studies' descriptions of AF systems and their development and implementation. RESULTS: The search resulted in 2125 studies that were screened for eligibility, of which 12 (0.56%); 2012-2020) were included. These studies described the development and implementation processes heterogeneously in terms of study aims, study targets, target groups, methods, and theoretical underpinnings. Few studies have explicitly explained how choices for the development and implementation of AF systems were substantiated by the TMFs. The conceptual framework provided insights into what is reported on the development and implementation process and revealed underreported AF system constructs (eg, AF system design; engagement with the AF system; and comparison, goal setting, and action planning) and development and implementation (eg, champions) constructs. CONCLUSIONS: This scoping review showed the current heterogeneous reporting of AF systems and their development and implementation processes and exemplified how interdisciplinary TMFs can (and should) be balanced in a conceptual framework to capture relevant AF systems and development and implementation constructs. Thereby, it provides a concrete checklist and overall guidance that supports the professionalization and harmonization of AF system development and implementation. For the development and implementation of future AF systems and other eHealth technologies, researchers and health care workers should be supported in selecting and integrating TMFs into their development and implementation process and encouraged to explicitly report on theoretical underpinnings and the substantiation of choices.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Retroalimentação , Pessoal de Saúde , Hospitais , Humanos
4.
Cell ; 185(7): 1240-1256.e30, 2022 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-35305313

RESUMO

We developed a miniaturized two-photon microscope (MINI2P) for fast, high-resolution, multiplane calcium imaging of over 1,000 neurons at a time in freely moving mice. With a microscope weight below 3 g and a highly flexible connection cable, MINI2P allowed stable imaging with no impediment of behavior in a variety of assays compared to untethered, unimplanted animals. The improved cell yield was achieved through a optical system design featuring an enlarged field of view (FOV) and a microtunable lens with increased z-scanning range and speed that allows fast and stable imaging of multiple interleaved planes, as well as 3D functional imaging. Successive imaging across multiple, adjacent FOVs enabled recordings from more than 10,000 neurons in the same animal. Large-scale proof-of-principle data were obtained from cell populations in visual cortex, medial entorhinal cortex, and hippocampus, revealing spatial tuning of cells in all areas.


Assuntos
Cálcio , Córtex Visual , Animais , Córtex Entorrinal , Hipocampo , Camundongos , Microscopia , Neurônios/fisiologia
5.
Artif Intell Med ; 123: 102216, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34998519

RESUMO

OBJECTIVE: Antimicrobial resistance (AMR) is a global threat to health and healthcare. In response to the growing AMR burden, research funding also increased. However, a comprehensive overview of the research output, including conceptual, temporal, and geographical trends, is missing. Therefore, this study uses topic modelling, a machine learning approach, to reveal the scientific evolution of AMR research and its trends, and provides an interactive user interface for further analyses. METHODS: Structural topic modelling (STM) was applied on a text corpus resulting from a PubMed query comprising AMR articles (1999-2018). A topic network was established and topic trends were analysed by frequency, proportion, and importance over time and space. RESULTS: In total, 88 topics were identified in 158,616 articles from 166 countries. AMR publications increased by 450% between 1999 and 2018, emphasizing the vibrancy of the field. Prominent topics in 2018 were Strategies for emerging resistances and diseases, Nanoparticles, and Stewardship. Emerging topics included Water and environment, and Sequencing. Geographical trends showed prominence of Multidrug-resistant tuberculosis (MDR-TB) in the WHO African Region, corresponding with the MDR-TB burden. China and India were growing contributors in recent years, following the United States of America as overall lead contributor. CONCLUSION: This study provides a comprehensive overview of the AMR research output thereby revealing the AMR research response to the increased AMR burden. Both the results and the publicly available interactive database serve as a base to inform and optimise future research.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Antibacterianos/uso terapêutico , China , Índia
6.
J Med Internet Res ; 24(1): e31858, 2022 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-35084359

RESUMO

BACKGROUND: Thorough holistic development of eHealth can contribute to a good fit among the technology, its users, and the context. However, despite the availability of frameworks, not much is known about specific research activities for different aims, phases, and settings. This results in researchers having to reinvent the wheel. Consequently, there is a need to synthesize existing knowledge on research activities for participatory eHealth development processes. OBJECTIVE: The 3 main goals of this review are to create an overview of the development strategies used in studies based on the CeHRes (Center for eHealth Research) Roadmap, create an overview of the goals for which these methods can be used, and provide insight into the lessons learned about these methods. METHODS: We included eHealth development studies that were based on the phases and/or principles of the CeHRes Roadmap. This framework was selected because of its focus on participatory, iterative eHealth design in context and to limit the scope of this review. Data were extracted about the type of strategy used, rationale for using the strategy, research questions, and reported information on lessons learned. The most frequently mentioned lessons learned were summarized using a narrative, inductive approach. RESULTS: In the included 160 papers, a distinction was made between overarching development methods (n=10) and products (n=7). Methods are used to gather new data, whereas products can be used to synthesize previously collected data and support the collection of new data. The identified methods were focus groups, interviews, questionnaires, usability tests, literature studies, desk research, log data analyses, card sorting, Delphi studies, and experience sampling. The identified products were prototypes, requirements, stakeholder maps, values, behavior change strategies, personas, and business models. Examples of how these methods and products were applied in the development process and information about lessons learned were provided. CONCLUSIONS: This study shows that there is a plethora of methods and products that can be used at different points in the development process and in different settings. To do justice to the complexity of eHealth development, it seems that multiple strategies should be combined. In addition, we found no evidence for an optimal single step-by-step approach to develop eHealth. Rather, researchers need to select the most suitable research methods for their research objectives, the context in which data are collected, and the characteristics of the participants. This study serves as a first step toward creating a toolkit to support researchers in applying the CeHRes Roadmap to practice. In this way, they can shape the most suitable and efficient eHealth development process.


Assuntos
Telemedicina , Terapia Comportamental , Grupos Focais , Humanos , Projetos de Pesquisa , Inquéritos e Questionários
7.
Front Microbiol ; 12: 743939, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34777290

RESUMO

Objectives: Data and data visualization are integral parts of (clinical) decision-making in general and stewardship (antimicrobial stewardship, infection control, and institutional surveillance) in particular. However, systematic research on the use of data visualization in stewardship is lacking. This study aimed at filling this gap by creating a visual dictionary of stewardship through an assessment of data visualization (i.e., graphical representation of quantitative information) in stewardship research. Methods: A random sample of 150 data visualizations from published research articles on stewardship were assessed (excluding geographical maps and flowcharts). The visualization vocabulary (content) and design space (design elements) were combined to create a visual dictionary. Additionally, visualization errors, chart junk, and quality were assessed to identify problems in current visualizations and to provide improvement recommendations. Results: Despite a heterogeneous use of data visualization, distinct combinations of graphical elements to reflect stewardship data were identified. In general, bar (n = 54; 36.0%) and line charts (n = 42; 28.1%) were preferred visualization types. Visualization problems comprised color scheme mismatches, double y-axis, hidden data points through overlaps, and chart junk. Recommendations were derived that can help to clarify visual communication, improve color use for grouping/stratifying, improve the display of magnitude, and match visualizations to scientific standards. Conclusion: Results of this study can be used to guide data visualization creators in designing visualizations that fit the data and visual habits of the stewardship target audience. Additionally, the results can provide the basis to further expand the visual dictionary of stewardship toward more effective visualizations that improve data insights, knowledge, and clinical decision-making.

8.
J Cell Sci ; 134(5)2021 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-33589501

RESUMO

Staphylococcus aureus infects ∼30% of the human population and causes a spectrum of pathologies ranging from mild skin infections to life-threatening invasive diseases. The strict host specificity of its virulence factors has severely limited the accuracy of in vivo models for the development of vaccines and therapeutics. To resolve this, we generated a humanised zebrafish model and determined that neutrophil-specific expression of the human C5a receptor conferred susceptibility to the S. aureus toxins PVL and HlgCB, leading to reduced neutrophil numbers at the site of infection and increased infection-associated mortality. These results show that humanised zebrafish provide a valuable platform to study the contribution of human-specific S. aureus virulence factors to infection in vivo that could facilitate the development of novel therapeutic approaches and essential vaccines.


Assuntos
Staphylococcus aureus , Fatores de Virulência , Animais , Humanos , Receptor da Anafilatoxina C5a/genética , Staphylococcus aureus/genética , Virulência , Fatores de Virulência/genética , Peixe-Zebra
9.
J Med Internet Res ; 22(10): e20404, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33095173

RESUMO

BACKGROUND: eHealth technologies aim to change users' health-related behavior. Persuasive design and system features can make an eHealth technology more motivating, engaging, or supportive to its users. The Persuasive Systems Design (PSD) model incorporates software features that have the possibility to increase the persuasiveness of technologies. However, the effects of specific PSD software features on the effectiveness of an intervention are still largely unknown. The Perceived Persuasiveness Questionnaire (PPQ) was developed to gain insight into the working mechanisms of persuasive technologies. Although the PPQ seems to be a suitable method for measuring subjective persuasiveness, it needs to be further evaluated to determine how suitable it is for measuring perceived persuasiveness among the public. OBJECTIVE: This study aims to evaluate the face and construct validity of the PPQ, identify points of improvement, and provide suggestions for further development of the PPQ. METHODS: A web-based closed-ended card-sort study was performed wherein participants grouped existing PPQ items under existing PPQ constructs. Participants were invited via a Massive Open Online Course on eHealth. A total of 398 people (average age 44.15 years, SD 15.17; 251/398, 63.1% women) completed the card sort. Face validity was evaluated by determining the item-level agreement of the original PPQ constructs. Construct validity was evaluated by determining the construct in which each item was placed most often, regardless of the original placement and how often 2 items were (regardless of the constructs) paired together and what interitem correlations were according to a cluster analysis. RESULTS: Four PPQ constructs obtained relatively high face validity scores: perceived social support, use continuance, perceived credibility, and perceived effort. Item-level agreement on the other constructs was relatively low. Item-level agreement for almost all constructs, except perceived effort and perceived effectiveness, would increase if items would be grouped differently. Finally, a cluster analysis of the PPQ indicated that the strengths of the newly identified 9 clusters varied strongly. Unchanged strong clusters were only found for perceived credibility support, perceived social support, and use continuance. The placement of the other items was much more spread out over the other constructs, suggesting an overlap between them. CONCLUSIONS: The findings of this study provide a solid starting point toward a redesigned PPQ that is a true asset to the field of persuasiveness research. To achieve this, we advocate that the redesigned PPQ should adhere more closely to what persuasiveness is according to the PSD model and to the mental models of potential end users of technology. The revised PPQ should, for example, enquire if the user thinks anything is done to provide task support but not how this is done exactly.


Assuntos
Motivação/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Comunicação Persuasiva , Inquéritos e Questionários , Adulto Jovem
10.
PLoS One ; 14(4): e0215592, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31002727

RESUMO

The neutrophil enzyme myeloperoxidase (MPO) is a major enzyme made by neutrophils to generate antimicrobial and immunomodulatory compounds, notably hypochlorous acid (HOCl), amplifying their capacity for destroying pathogens and regulating inflammation. Despite its roles in innate immunity, the importance of MPO in preventing infection is unclear, as individuals with MPO deficiency are asymptomatic with the exception of an increased risk of candidiasis. Dysregulation of MPO activity is also linked with inflammatory conditions such as atherosclerosis, emphasising a need to understand the roles of the enzyme in greater detail. Consequently, new tools for investigating granular dynamics in vivo can provide useful insights into how MPO localises within neutrophils, aiding understanding of its role in preventing and exacerbating disease. The zebrafish is a powerful model for investigating the immune system in vivo, as it is genetically tractable, and optically transparent. To visualise MPO activity within zebrafish neutrophils, we created a genetic construct that expresses human MPO as a fusion protein with a C-terminal fluorescent tag, driven by the neutrophil-specific promoter lyz. After introducing the construct into the zebrafish genome by Tol2 transgenesis, we established the Tg(lyz:Hsa.MPO-mEmerald,cmlc2:EGFP)sh496 line, and confirmed transgene expression in zebrafish neutrophils. We observed localisation of MPO-mEmerald within a subcellular location resembling neutrophil granules, mirroring MPO in human neutrophils. In Spotless (mpxNL144) larvae-which express a non-functional zebrafish myeloperoxidase-the MPO-mEmerald transgene does not disrupt neutrophil migration to sites of infection or inflammation, suggesting that it is a suitable line for the study of neutrophil granule function. We present a new transgenic line that can be used to investigate neutrophil granule dynamics in vivo without disrupting neutrophil behaviour, with potential applications in studying processing and maturation of MPO during development.


Assuntos
Proteínas de Fluorescência Verde/metabolismo , Proteínas Luminescentes/metabolismo , Neutrófilos/enzimologia , Peroxidase/metabolismo , Peixe-Zebra/metabolismo , Animais , Animais Geneticamente Modificados , Proteínas de Fluorescência Verde/genética , Humanos , Larva/genética , Larva/metabolismo , Proteínas Luminescentes/genética , Microscopia Confocal , Microscopia de Fluorescência , Peroxidase/genética , Transgenes/genética , Peixe-Zebra/genética , Proteína Vermelha Fluorescente
11.
Microbiol Spectr ; 7(2)2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30927347

RESUMO

Staphylococcus aureus has become a serious threat to human health. In addition to having increased antibiotic resistance, the bacterium is a master at adapting to its host by evading almost every facet of the immune system, the so-called immune evasion proteins. Many of these immune evasion proteins target neutrophils, the most important immune cells in clearing S. aureus infections. The neutrophil attacks pathogens via a plethora of strategies. Therefore, it is no surprise that S. aureus has evolved numerous immune evasion strategies at almost every level imaginable. In this review we discuss step by step the aspects of neutrophil-mediated killing of S. aureus, such as neutrophil activation, migration to the site of infection, bacterial opsonization, phagocytosis, and subsequent neutrophil-mediated killing. After each section we discuss how S. aureus evasion molecules are able to resist the neutrophil attack of these different steps. To date, around 40 immune evasion molecules of S. aureus are known, but its repertoire is still expanding due to the discovery of new evasion proteins and the addition of new functions to already identified evasion proteins. Interestingly, because the different parts of neutrophil attack are redundant, the evasion molecules display redundant functions as well. Knowing how and with which proteins S. aureus is evading the immune system is important in understanding the pathophysiology of this pathogen. This knowledge is crucial for the development of therapeutic approaches that aim to clear staphylococcal infections.


Assuntos
Interações Hospedeiro-Patógeno/imunologia , Evasão da Resposta Imune/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Quimiotaxia/imunologia , Endotélio/imunologia , Humanos , Imunidade Inata/imunologia , Neutrófilos/imunologia , Neutrófilos/microbiologia , Fagocitose/imunologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/patogenicidade
12.
Arch Biochem Biophys ; 645: 1-11, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29524428

RESUMO

Staphylococcus aureus and related species are highly adapted to their hosts and have evolved numerous strategies to evade the immune system. S. aureus shows resistance to killing following uptake into the phagosome, which suggests that the bacterium evades intracellular killing mechanisms used by neutrophils. We recently discovered an S. aureus protein (SPIN for Staphylococcal Peroxidase INhibitor) that binds to and inhibits myeloperoxidase (MPO), a major player in the oxidative defense of neutrophils. To allow for comparative studies between multiple SPIN sequences, we identified a panel of homologs from species closely related to S. aureus. Characterization of these proteins revealed that SPIN molecules from S. agnetis, S. delphini, S. schleiferi, and S. intermedius all bind human MPO with nanomolar affinities, and that those from S. delphini, S. schleiferi, and S. intermedius inhibit human MPO in a dose-dependent manner. A 2.4 Šresolution co-crystal structure of SPIN-delphini bound to recombinant human MPO allowed us to identify conserved structural features of SPIN proteins, and to propose sequence-dependent physical explanations for why SPIN-aureus binds human MPO with higher affinity than SPIN-delphini. Together, these studies expand our understanding of MPO binding and inhibition by a recently identified component of the staphylococcal innate immune evasion arsenal.


Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Peroxidase/antagonistas & inibidores , Staphylococcus/química , Sequência de Aminoácidos , Inibidores Enzimáticos/metabolismo , Humanos , Modelos Moleculares , Peroxidase/química , Peroxidase/metabolismo , Conformação Proteica
13.
J Biol Chem ; 293(12): 4468-4477, 2018 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-29414776

RESUMO

Staphylococcus aureus is a versatile pathogen capable of causing a broad range of diseases in many different hosts. S. aureus can adapt to its host through modification of its genome (e.g. by acquisition and exchange of mobile genetic elements that encode host-specific virulence factors). Recently, the prophage φSaeq1 was discovered in S. aureus strains from six different clonal lineages almost exclusively isolated from equids. Within this phage, we discovered a novel variant of staphylococcal complement inhibitor (SCIN), a secreted protein that interferes with activation of the human complement system, an important line of host defense. We here show that this equine variant of SCIN, eqSCIN, is a potent blocker of equine complement system activation and subsequent phagocytosis of bacteria by phagocytes. Mechanistic studies indicate that eqSCIN blocks equine complement activation by specific inhibition of the C3 convertase enzyme (C3bBb). Whereas SCIN-A from human S. aureus isolates exclusively inhibits human complement, eqSCIN represents the first animal-adapted SCIN variant that functions in a broader range of hosts (horses, humans, and pigs). Binding analyses suggest that the human-specific activity of SCIN-A is related to amino acid differences on both sides of the SCIN-C3b interface. These data suggest that modification of this phage-encoded complement inhibitor plays a role in the host adaptation of S. aureus and are important to understand how this pathogen transfers between different hosts.


Assuntos
Convertases de Complemento C3-C5/metabolismo , Complemento C3b/antagonistas & inibidores , Proteínas Inativadoras do Complemento/metabolismo , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo , Fatores de Virulência/metabolismo , Animais , Complemento C3b/metabolismo , Proteínas Inativadoras do Complemento/química , Hemólise , Cavalos , Especificidade de Hospedeiro , Humanos , Fagocitose , Ligação Proteica , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/isolamento & purificação , Suínos , Fatores de Virulência/química
14.
J Biol Chem ; 293(7): 2260-2271, 2018 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-29306874

RESUMO

The heme-containing enzyme myeloperoxidase (MPO) is critical for optimal antimicrobial activity of human neutrophils. We recently discovered that the bacterium Staphylococcus aureus expresses a novel immune evasion protein, called SPIN, that binds tightly to MPO, inhibits MPO activity, and contributes to bacterial survival following phagocytosis. A co-crystal structure of SPIN bound to MPO suggested that SPIN blocks substrate access to the catalytic heme by inserting an N-terminal ß-hairpin into the MPO active-site channel. Here, we describe a series of experiments that more completely define the structure/function relationships of SPIN. Whereas the SPIN N terminus adopts a ß-hairpin confirmation upon binding to MPO, the solution NMR studies presented here are consistent with this region of SPIN being dynamically structured in the unbound state. Curiously, whereas the N-terminal ß-hairpin of SPIN accounts for ∼55% of the buried surface area in the SPIN-MPO complex, its deletion did not significantly change the affinity of SPIN for MPO but did eliminate the ability of SPIN to inhibit MPO. The flexible nature of the SPIN N terminus rendered it susceptible to proteolytic degradation by a series of chymotrypsin-like proteases found within neutrophil granules, thereby abrogating SPIN activity. Degradation of SPIN was prevented by the S. aureus immune evasion protein Eap, which acts as a selective inhibitor of neutrophil serine proteases. Together, these studies provide insight into MPO inhibition by SPIN and suggest possible functional synergy between two distinct classes of S. aureus immune evasion proteins.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Peroxidase/química , Peroxidase/metabolismo , Infecções Estafilocócicas/enzimologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo , Motivos de Aminoácidos , Proteínas de Bactérias/genética , Cristalografia por Raios X , Humanos , Espectroscopia de Ressonância Magnética , Peroxidase/genética , Ligação Proteica , Staphylococcus aureus/química , Staphylococcus aureus/genética
15.
Proc Natl Acad Sci U S A ; 114(35): 9439-9444, 2017 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-28808028

RESUMO

Staphylococcus aureus is highly adapted to its host and has evolved many strategies to resist opsonization and phagocytosis. Even after uptake by neutrophils, S. aureus shows resistance to killing, which suggests the presence of phagosomal immune evasion molecules. With the aid of secretome phage display, we identified a highly conserved protein that specifically binds and inhibits human myeloperoxidase (MPO), a major player in the oxidative defense of neutrophils. We have named this protein "staphylococcal peroxidase inhibitor" (SPIN). To gain insight into inhibition of MPO by SPIN, we solved the cocrystal structure of SPIN bound to a recombinant form of human MPO at 2.4-Å resolution. This structure reveals that SPIN acts as a molecular plug that prevents H2O2 substrate access to the MPO active site. In subsequent experiments, we observed that SPIN expression increases inside the neutrophil phagosome, where MPO is located, compared with outside the neutrophil. Moreover, bacteria with a deleted gene encoding SPIN showed decreased survival compared with WT bacteria after phagocytosis by neutrophils. Taken together, our results demonstrate that S. aureus secretes a unique proteinaceous MPO inhibitor to enhance survival by interfering with MPO-mediated killing.


Assuntos
Peroxidase/antagonistas & inibidores , Proteínas de Bactérias , Regulação Bacteriana da Expressão Gênica , Humanos , Modelos Moleculares , Neutrófilos/fisiologia , Fagocitose , Ligação Proteica , Conformação Proteica , Staphylococcus aureus/metabolismo , Regulação para Cima
16.
Infect Dis Rep ; 9(1): 6829, 2017 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-28458796

RESUMO

The rise of antimicrobial resistance (AMR) is a severe global health problem. Tackling this problem requires the prudent prescribing of antimicrobials. This is promoted through Antimicrobial Stewardship Programs (ASPs). In this position paper we describe i) how a socio-technical multidisciplinary approach (based on the CeHRes Roadmap) can be applied in the development and implementation of Antimicrobial Stewardship technologies and ii) how this approach can be of value to support Antimicrobial Stewardship in practice. The CeHRes Roadmap entails five different phases to explore and test how an eHealth technology can be tailored to the target group and successfully implemented in practice: i) contextual inquiry, ii) value specification, iii) design, iv) operationalization, v) evaluation. In this position paper we describe the lessons learned from research and practice to guide future developments of technology based ASP interventions. Since AMR is a huge wicked problem on a global level, it requires innovative methods and models to empower general public and professionals to be proactive rather than reactive in a digitalized world. We highlight how to combat the dangerous rise of antimicrobial resistance in the future.

17.
Sci Rep ; 7: 43889, 2017 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-28266573

RESUMO

We present integration vectors for Staphylococcus aureus encoding the fluorescent reporters mAmetrine, CFP, sGFP, YFP, mCherry and mKate. The expression is driven either from the sarA-P1 promoter or from any other promoter of choice. The reporter can be inserted markerless in the chromosome of a wide range of S. aureus strains. The integration site chosen does not disrupt any open reading frame, provides good expression, and has no detectable effect on the strains physiology. As an intermediate construct, we present a set of replicating plasmids containing the same fluorescent reporters. Also in these reporter plasmids the sarA-P1 promoter can be replaced by any other promoter of interest for expression studies. Cassettes from the replication plasmids can be readily swapped with the integration vector. With these constructs it becomes possible to monitor reporters of separate fluorescent wavelengths simultaneously.


Assuntos
Técnicas de Introdução de Genes/métodos , Genes Reporter , Proteínas Luminescentes/análise , Staphylococcus aureus/genética , Vetores Genéticos , Proteínas Luminescentes/genética , Plasmídeos
18.
Am J Infect Control ; 45(4): 365-371, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28089673

RESUMO

BACKGROUND: Current clinical decision support systems (CDSSs) for antimicrobial stewardship programs (ASPs) are guideline- or expert-driven. They are focused on (clinical) content, not on supporting real-time workflow. Thus, CDSSs fail to optimally support prudent antimicrobial prescribing in daily practice. Our aim was to demonstrate why and how participatory development (involving end-users and other stakeholders) can contribute to the success of CDSSs in ASPs. METHODS: A mixed-methods approach was applied, combining scenario-based prototype evaluations (to support verbalization of work processes and out-of-the-box thinking) among 6 medical resident physicians with an online questionnaire (to cross-reference findings of the prototype evaluations) among 54 Dutch physicians. RESULTS: The prototype evaluations resulted in insight into the end-users and their way of working, as well as their needs and expectations. The online questionnaire that was distributed among a larger group of medical specialists, including lung and infection experts, complemented the findings of the prototype evaluations. It revealed a say/do problem concerning the unrecognized need of support for selecting diagnostic tests. CONCLUSIONS: Low-fidelity prototypes of a technology allow researchers to get to know the end-users, their way of working, and their work context. Involving experts allows technology developers to continuously check the fit between technology and clinical practice. The combination enables the participatory development of technology to successfully support ASPs.


Assuntos
Anti-Infecciosos/uso terapêutico , Sistemas de Apoio a Decisões Clínicas , Uso de Medicamentos/normas , Adulto , Feminino , Humanos , Masculino , Países Baixos , Política Organizacional , Médicos , Inquéritos e Questionários
19.
J Leukoc Biol ; 100(5): 1005-1010, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27334228

RESUMO

Neutrophils are the first line of defense after a pathogen has breached the epithelial barriers, and unimpaired neutrophil functions are essential to clear infections. Staphylococcus aureus is a prevalent human pathogen that is able to withstand neutrophil killing, yet the mechanisms used by S. aureus to inhibit neutrophil clearance remain incompletely defined. The production of reactive oxygen species (ROS) is a vital neutrophil antimicrobial mechanism. Herein, we test the hypothesis that S. aureus uses the SaeR/S two-component gene regulatory system to produce virulence factors that reduce neutrophil ROS production. With the use of ROS probes, the temporal and overall production of neutrophil ROS was assessed during exposure to the clinically relevant S. aureus USA300 (strain LAC) and its isogenic mutant LACΔsaeR/S Our results demonstrated that SaeR/S-regulated factors do not inhibit neutrophil superoxide (O2-) production. However, subsequent neutrophil ROS production was significantly reduced during exposure to LAC compared with LACΔsaeR/S In addition, neutrophil H2O2 production was reduced significantly by SaeR/S-regulated factors by a mechanism independent of catalase. Consequently, the reduction in neutrophil H2O2 resulted in decreased production of the highly antimicrobial agent hypochlorous acid/hypochlorite anion (HOCl/-OCl). These findings suggest a new evasion strategy used by S. aureus to diminish a vital neutrophil antimicrobial mechanism.


Assuntos
Proteínas de Bactérias/fisiologia , Regulação Bacteriana da Expressão Gênica , Neutrófilos/metabolismo , Proteínas Quinases/fisiologia , Espécies Reativas de Oxigênio/sangue , Staphylococcus aureus/fisiologia , Fatores de Transcrição/fisiologia , Proteínas de Bactérias/genética , Catalase/análise , Humanos , Peróxido de Hidrogênio/sangue , Ácido Hipocloroso/sangue , Luminol , Neutrófilos/microbiologia , Fagocitose , Proteínas Quinases/deficiência , Proteínas Quinases/genética , Explosão Respiratória , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Superóxidos/sangue , Fatores de Transcrição/genética , Virulência
20.
BMC Biol ; 13: 52, 2015 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-26187647

RESUMO

BACKGROUND: Malaria invasion of red blood cells involves multiple parasite-specific targets that are easily accessible to inhibitory compounds, making it an attractive target for antimalarial development. However, no current antimalarial agents act against host cell invasion. RESULTS: Here, we demonstrate that the clinically used macrolide antibiotic azithromycin, which is known to kill human malaria asexual blood-stage parasites by blocking protein synthesis in their apicoplast, is also a rapid inhibitor of red blood cell invasion in human (Plasmodium falciparum) and rodent (P. berghei) malarias. Multiple lines of evidence demonstrate that the action of azithromycin in inhibiting parasite invasion of red blood cells is independent of its inhibition of protein synthesis in the parasite apicoplast, opening up a new strategy to develop a single drug with multiple parasite targets. We identified derivatives of azithromycin and erythromycin that are better invasion inhibitors than parent compounds, offering promise for development of this novel antimalarial strategy. CONCLUSIONS: Safe and effective macrolide antibiotics with dual modalities could be developed to combat malaria and reduce the parasite's options for resistance.


Assuntos
Antimaláricos/farmacologia , Azitromicina/farmacologia , Eritrócitos/parasitologia , Eritromicina/farmacologia , Malária/tratamento farmacológico , Plasmodium berghei/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Animais , Anopheles , Antimaláricos/química , Azitromicina/química , Eritromicina/química , Interações Hospedeiro-Parasita/efeitos dos fármacos , Humanos , Malária/parasitologia , Camundongos , Plasmodium berghei/fisiologia , Plasmodium falciparum/fisiologia
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