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The aim of this study is to investigate the impact of different logistic regression estimators applied to RDS studies via simulation and the analysis of empirical data. Four simulated populations were created with different connectivity characteristics. Each simulated individual received two attributes, one of them associated to the infection process. RDS samples with different sizes were obtained. The observed coverage of three logistic regression estimators were applied to assess the association between the attributes and the infection status. In simulated datasets, unweighted logistic regression estimators emerged as the best option, although all estimators showed a fairly good performance. In the empirical dataset, the performance of weighted estimators presented an unexpected behavior, making them a risky option. The unweighted logistic regression estimator is a reliable option to be applied to RDS samples, with a performance roughly similar to random samples and, therefore, should be the preferred option.

The study aimed to optimize qPCR reactions using oligonucleotides from the first Brazilian molecular diagnostic kit for leprosy on a portable platform (Q3-Plus). In addition, we sought to develop a simplified protocol for DNA extraction that met point-of-care criteria. During optimization on the Q3-Plus, optical parameters, thresholds, and cutoffs for the 16S rRNA and RLEP targets of M. leprae were established using synthetic DNA, purified DNA from M. leprae, and pre-characterized clinical samples. For the simplified extraction protocol, different lysis solutions were evaluated using chaotropic agents, and purification was carried out by transferring the lysed material to FTA cards. The complete protocol (simplified extraction + qPCR on the portable platform) was then evaluated with pre-characterized clinical skin biopsy samples and compared with standard equipment (QuantStudio-5). LOD95% for the optimized reactions was 113.31 genome-equivalents/μL for 16S rRNA and 17.70 genome-equivalents/μL for RLEP. Among the lysis solutions, the best-performing was composed of urea (2 M), which provided good dissolution of the skin fragment and a lower Ct value, indicating higher concentrations of DNA. The complete technological solution showed a sensitivity of 52% in reactions. Our results highlight the need for additional optimization to deal with paucibacillary samples, but also demonstrate the feasibility of the portable platform for the qPCR detection of M. leprae DNA in low infrastructure settings. Author summary: The diagnosis of tropical or neglected infectious diseases, such as leprosy, is highly dependent on techniques that are not very sensitive or very laborious, such as optical microscopy or culture. More sensitive and specific molecular tests are only available in urban centers, where there is a specialized workforce and adequate infrastructure. However, a large portion of the population does not have access to such medical services, either due to financial or distance issues. Thus, performing diagnostic tests at the point of care (POC) provides agility in diagnosis, avoiding the need for patients to travel to medical centers or transport biological samples to clinical analysis centers, ensuring that this population has access to diagnostic tests, even in remote areas or with poor infrastructure. In this work, we optimize and validate, on a laboratory scale, simplified versions of all the procedures necessary to perform molecular tests, from collection and DNA extraction to the detection of genomic targets using portable qPCR equipment. The results presented here are the basis of a novel tool with potential to increase a leprosy screening test in remote areas, facilitating the active search of positive cases and monitoring by health authorities responsible for underserved populations. [ABSTRACT FROM AUTHOR]

Background: Propolis possesses many bioactive compounds that could modulate the gut microbiota and reduce the production of uremic toxins in patients with chronic kidney disease (CKD) undergoing hemodialysis (HD). This clinical trial aimed to evaluate the effects of propolis on the gut microbiota profile and uremic toxin plasma levels in HD patients. These are secondary analyses from a previous double-blind, randomized clinical study, with 42 patients divided into two groups: the placebo and propolis group received 400 mg of green propolis extract/day for eight weeks. Indole-3 acetic acid (IAA), indoxyl sulfate (IS), and p-cresyl sulfate (p-CS) plasma levels were evaluated by reversed-phase liquid chromatography, and cytokines were investigated using the multiplex assay (Bio-Plex Magpix®). The fecal microbiota composition was analyzed in a subgroup of patients (n = 6) using a commercial kit for fecal DNA extraction. The V4 region of the 16S rRNA gene was then amplified by the polymerase chain reaction (PCR) using short-read sequencing on the Illumina NovaSeq PE250 platform in a subgroup. Forty-one patients completed the study, 20 in the placebo group and 21 in the propolis group. There was a positive correlation between IAA and TNF-α (r = 0.53, p = 0.01), IL-2 (r = 0.66, p = 0.002), and between pCS and IL-7 (r = 0.46, p = 0.04) at the baseline. No significant changes were observed in the values of uremic toxins after the intervention. Despite not being significant, microbial evenness and observed richness increased following the propolis intervention. Counts of the Fusobacteria species showed a positive correlation with IS, while counts of Firmicutes, Lentisphaerae, and Proteobacteria phyla were negatively correlated with IS. Two months of propolis supplementation did not reduce the plasma levels of uremic toxins (IAA, IS, and p-CS) or change the fecal microbiota. [ABSTRACT FROM AUTHOR]

Introduction: Sporotrichosis is a subcutaneous mycosis caused by fungi of the genus Sporothrix sp. Phenotypic and genotypic differences have been associated with their geographic distribution, virulence, or clinical manifestation of sporotrichosis. In the past decade, the interest in identifying species of the Sporothrix sp. has been increasing, due to its epidemiological importance and, in consequence, is important to know how to preserve them for future studies, in culture collection. Aims: The purposes of this study were to analyze the global distribution of environmental isolates and/or causal agents of sporotrichosis identified by polyphasic taxonomy, with mandatory use of molecular identification, and to evaluate the percentages and distribution of isolates stored in culture collections. Methods: A systematic review of articles on animal and human sporotrichosis and/or environmental isolation of the fungus, from 2007 to 2023, was done. Results: Our results demonstrated that, S. globosa, S. schenckii, and S. brasiliensis were the most identified species. With respect to the deposit and maintenance of species, we observed that only 17% of the strains of Sporothrix sp. isolated in the world are preserved in a culture collection. Conclusions: This systematic review confirmed a difficulty in obtaining the frequency of Sporothrix species stored in culture collection and insufficient data on the molecular identification mainly of animal sporotrichosis and isolation of Sporothrix sp. in environmental samples. [ABSTRACT FROM AUTHOR]

Purpose Activity/remission differentiation is a great challenge in the follow-up and treatment of sarcoidosis patients. Angiotensin-converting enzyme (ACE) and high sensitivity C-reactive protein (hs-CRP) were proposed as sarcoidosis biomarkers. More recently, chitotriosidase (CHITO) has been described as a better alternative. This study has the aim to evaluate the association of CHITO activity, ACE, hs-CRP or a combination of these biomarkers and to construct a clinical algorithm to differentiate between sarcoidosis activity/remission status. Methods Forty-six patients with either active sarcoidosis or sarcoidosis in remission and 21 healthy individuals were included. ACE, hs-CRP, and CHITO were evaluated in serum samples. Comparisons of the laboratory variable means among groups were performed by linear models. The cutoff points of the biomarkers for activity/remission differentiation were calculated using the Youden's index. Biomarker cutoff points and decision tree classifier (DTC) performance were estimated by their leave-one-out cross-validation (LOOCV) accuracy (Acc), sensitivity (Se), and specificity (Sp). Results A 55% mean Se and a 100% mean Sp were found for CHITO, while an 88% Se and a 47% Sp were found for ACE, and a 66% Se and a 68% Sp for hs-CRP cutoff points for activity/remission differentiation. The DTC algorithm with CHITO, hs-CRP, and ACE information had an LOOCV mean Acc of 82%, Se of 78%, and Sp of 89% for sarcoidosis activity/remission differentiation. Conclusions The algorithm involving CHITO, hs-CRP, and ACE could be a suitable strategy for differentiation between sarcoidosis activity/remission status., Author(s): Mariana Carneiro Lopes [sup.1] , Thaís Porto Amadeu [sup.1] , Marcelo Ribeiro-Alves [sup.2] , Claudia Henrique da Costa [sup.1] , Luciana Silva Rodrigues [sup.1] , Elisabeth Jauhar Cardoso Bessa [...]