O26 Polysaccharides as Key Players in Enteropathogenic E. coli Immune Evasion and Vaccine Development.

Enteropathogenic Escherichia coli (EPEC) produce a capsule of polysaccharides identical to those composing the O-antigen polysaccharide of its LPS (lipopolysaccharide) molecules. In light of this, the impact of O26 polysaccharides on the immune evasion mechanisms of capsulated O26 EPEC compared to non-capsulated enterohemorrhagic Escherichia coli (EHEC) was investigated. Our findings reveal that there was no significant difference between the levels in EPEC and EHEC of rhamnose (2.8:2.5), a molecule considered to be a PAMP (Pathogen Associated Molecular Patterns). However, the levels of glucose (10:1.69), heptose (3.6:0.89) and N-acetylglucosamine (4.5:2.10), were significantly higher in EPEC than EHEC, respectively. It was also observed that the presence of a capsule in EPEC inhibited the deposition of C3b on the bacterial surface and protected the pathogen against lysis by the complement system. In addition, the presence of a capsule also protected EPEC against phagocytosis by macrophages. However, the immune evasion provided by the capsule was overcome in the presence of anti-O26 polysaccharide antibodies, and additionally, these antibodies were able to inhibit O26 EPEC adhesion to human epithelial cells. Finally, the results indicate that O26 polysaccharides can generate an effective humoral immune response, making them promising antigens for the development of a vaccine against capsulated O26 E. coli.

Bibliometric Review on New Possibilities of Antimycobacterial Agents: Exploring Siderophore Desferrioxamine's Applications as an Antimicrobial Agent.

Mycobacteria cause tuberculosis and other serious diseases. Understanding their mechanisms of resistance to our immune system and exploring novel drugs are critical strategies to combat infections. A bibliometric analysis was performed to identify publication trends and critical research areas in the field of the antimicrobial activity of desferrioxamine. A total of twenty-four publications on the topic, from 2012 to 2023, were retrieved from databases including Web of Science, Scopus, PubMed, and Embase, using specific keywords. The quality of the publications was assessed using impact and productivity metrics, with an average annual publication rate of 2.1 articles. The United States emerged as the most productive country, with medicine (23.4%, 11 publications) and biochemistry, genetics, and molecular biology (21.3%, 10 publications) as the top research fields. The five most cited publications accounted for 672 citations, with a relatively low h-index (11:11). In conclusion, there has been a lack of publications on this topic in the last decade. The United States dominates production and publication in this area, and there appears to be limited exchange of knowledge, ideas, and technology within the field. Therefore, fostering international cooperation through funding is essential to facilitate further research and development of desferrioxamine-related studies.

SARS-CoV-2 Rapid Antigen Test Based on a New Anti-Nucleocapsid Protein Monoclonal Antibody: Development and Real-Time Validation.

SARS-CoV-2 diagnostic tests have become an important tool for pandemic control. Among the alternatives for COVID-19 diagnosis, antigen rapid diagnostic tests (Ag-RDT) are very convenient and widely used. However, as SARS-CoV-2 variants may continuously emerge, the replacement of tests and reagents may be required to maintain the sensitivity of Ag-RDTs. Here, we describe the development and validation of an Ag-RDT during an outbreak of the Omicron variant, including the characterization of a new monoclonal antibody (anti-DTC-N 1B3 mAb) that recognizes the Nucleocapsid protein (N). The anti-DTC-N 1B3 mAb recognized the sequence TFPPTEPKKDKKK located at the C-terminus of the N protein of main SARS-CoV-2 variants of concern. Accordingly, the Ag-RDT prototypes using the anti-DTC-N 1B3 mAB detected all the SARS-CoV-2 variants-Wuhan, Alpha, Gamma, Delta, P2 and Omicron. The performance of the best prototype (sensitivity of 95.2% for samples with Ct ≤ 25; specificity of 98.3% and overall accuracy of 85.0%) met the WHO recommendations. Moreover, results from a patients' follow-up study indicated that, if performed within the first three days after onset of symptoms, the Ag-RDT displayed 100% sensitivity. Thus, the new mAb and the Ag-RDT developed herein may constitute alternative tools for COVID-19 point-of-care diagnosis and epidemiological surveillance.

Effect of Silver Diamine Fluoride on the Bonding Properties to Caries-affected Dentin.

PURPOSE: To evaluate 1. the microtensile bond strength (µTBS) and in situ degree of conversion (DC) of adhesives applied using two bonding strategies after silver diamine fluoride (diamine) application on carious dentinal lesions, and 2. dentin etching patterns using SEM and energy dispersive x-ray spectroscopy. MATERIALS AND METHODS: Human molars were randomly divided into 12 experimental groups according to: 1. application of a silver diamine fluoride solution (carious dentinal lesion without silver diamine fluoride treatment [control], with 12% silver diamine fluoride [diamine 12%] or 38% silver diamine fluoride [diamine 38%]); 2. adhesives (Clearfil Universal Bond Quick [CUQ] and Scotchbond Universal [SBU]); 3. adhesive strategy (etch-and-rinse [ER] and self-etch [SE]). After restoration, the specimens were sectioned and submitted to µTBS testing. Sticks from each tooth were used for DC evaluation. To examine the changes induced by diamine before and after phosphoric acid treatment, SEM/EDX analysis was performed. Data from the µTBS and DC tests were analyzed using three-way ANOVA and Tukey's test (α = 0.05). RESULTS: Both concentrations of diamine resulted in a statistically significantly higher mean µTBS compared to the control (p < 0.0001). Diamine 38% showed a statistically significantly higher mean µTBS for both adhesives in SE mode compared to diamine 12% (p < 0.0001). The application of diamine to carious dentinal lesions did not significantly influence the mean DC values for either adhesive (p = 0.72). SBU showed a higher mean DC compared to CUQ (p = 0.03). After diamine treatment, there was an increase in the Ca peak intensity and the presence of residual silver ions mainly when diamine 38% was applied along with the SE approach. CONCLUSION: Independent of the adhesive application approach, the use of diamine may be a promising alternative to increase µTBS without jeopardizing the DC of the two adhesives in carious dentinal lesions.

Identification and seasonality of rhinovirus and respiratory syncytial virus in asthmatic children in tropical climate.

INTRODUCTION: Asthma is a disease that has been associated with the presence of different genetic and socio-environmental factors. OBJECTIVE: To identify and evaluate the seasonality of respiratory syncytial virus (RSV) and human rhinovirus (RV) in asthmatic children and adolescents in tropical climate, as well as to assess the socioeconomic and environmental factors involved. METHODS: The study was conducted in a referral hospital, where a total of 151 children were recruited with a respiratory infection. The International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a questionnaire were applied, and a skin prick test was performed. The nasal swab was collected to detect RV and RSV through molecular assay. National Meteorological Institute (INMET) database was the source of climatic information. RESULTS: The socio-environmental characterization of asthmatic children showed the family history of allergy, disturbed sleep at night, dry cough, allergic rhinitis, individuals sensitized to at least one mite. We identified RV in 75% of children with asthma and 66.7% of RSV in children with asthma. There was an association between the presence of RV and the dry season whereas the presence of the RSV was associated with the rainy season. Contributing to these results, a negative correlation was observed between the RSV and the wind speed and the maximum temperature (T. Max) and a positive correlation with precipitation. CONCLUSIONS: The results suggest a high prevalence of RV and RSV in asthmatic children and the seasonality of these viruses were present in different climatic periods. This has significant implications for understanding short- and long-term clinical complications in asthmatic patients.

Hermenêutica dos problemas éticos percebidos por profissionais da atenção primária / Hermeneutics of ethical problems perceived by professionals of primary care

O artigo interpreta os problemas éticos percebidos pelos profissionais da atenção primária em duas pesquisas qualitativas realizadas na região metropolitana de Porto Alegre. Os dados foram coletados em oito reuniães de discussão focal sobre os desafios éticos da prática, tendo como participantes diferentes profissionais da Estratégia Saúde da Família (ESF) de Campo Bom e de uma unidade básica de saúde (UBS) de São Leopoldo. A seguir, foram analisados na perspectiva da hermenêutica de profundidade, para identificar os problemas éticos, com especial atenção ao contexto e ao discurso dos profissionais. Problemas éticos entendidos como desafios não podem ter uma resposta dicotômica e não existem respostas imediatas, pedindo deliberação sobre caminhos possíveis de solução, exigindo criatividade e decisães de longo alcance, com avaliação contínua. As falas dos profissionais apontaram para problemas éticos relativos à demanda, aos processos de trabalho e ao sistema de saúde.