Interactions between DC-SIGN and the envelope protein from Dengue and Zika viruses: a structural perspective based on molecular dynamics and MM/GBSA analyses.

Zika virus (ZIKV) and dengue virus (DENV) share a lot of similarities being both phylogenetically closely related, share the same insect vector passage for reaching the host, affinity for the same carbohydrate receptor domains (CRDs), indicating feasible competition between them on the natural field. Here, we prospected interactions of both envelope proteins with a DC-SIGN, a transmembrane c-type lectine receptor with the most implicated CRD with the Flavivirus infection presents on dendritic cells involved in viruses replication processes into the host, and among rares CRD receptors susceptible to interacting with a broad of subtypes of DENV. Protein-protein docking procedures produced structures for molecular dynamics experiments, suggesting the most energetically favorable complex. The difference found in the deltaG results prompted the experimentation with molecular dynamics. To investigate further specific residues involved with such interactions we produced a decomposition analysis using molecular dynamics of the docked proteins evaluated afterward with the Generalized Born Surface Area method. Solvent-accessible surface area (SASA) analysis for both showed very similar but with a slight reduction for ZIKV_E, which agreed with residues SASA analysis highlighting regions more exposed in the ZIVK protein than in DENV. Despite residues PHE313 is reponsible for most of the interactions with the envelope of these arboviruses, ZIKV interacted with this residue in DC-SIGN with lower energies and using more interactions with not expexted residues GLU241 and ARG386. Taken together these results suggest better competitive interaction of ZIKV with the DC-SIGN receptor, particularly in the CRD portion.

Complications during transport of adult patients on extracorporeal membrane oxygenation.

INTRODUCTION: Transport on extracorporeal membrane oxygenation (ECMO) is a risky and complex procedure. Although most published data support the feasibility of interhospital transport on ECMO, data concerning intra-facility transportation and frequency and severity of complications during ECMO transport of adult patients are still scarce. The aim of this study was to assess transport arrangements and complications during intra and interhospital ECMO-supported patients transport at a high-volume ECMO center. METHODS: Retrospective single-center descriptive study evaluating the prevalence and severity of complications associated with the transportation of adult patients on ECMO support between 2014 and 2022 in our ECMO center. RESULTS: We performed 393 transfers of patients on ECMO support. Those comprised 206 intra-facility, 147 primary, 39 secondary and one tertiary transports. For primary and tertiary transportations, the average transfer length was 118.6 km (range 2.5-1446) and the mean total transport time was 5 h 40 min. The majority of transportations were made by ambulance (93.2%). Complications occurred in 12.7% of all transports and were more frequent in intra-facility and primary/tertiary transfers. Most complications were patient (46%) and staff related (26%). Risk category two was the most frequent (50%), and only five complications were classified as risk category 1 (10%). No deaths occurred during all patient transport. CONCLUSIONS: Most transports carry minor problems that entail a negligible risk to the patient. When ECMO-supported transport is performed by an experienced team, the severe complications are not related with an increased morbimortality.

Detection of non-tuberculosus mycobacteria (NTMs) in lung samples using 16S rRNA.

BACKGROUND: Non-tuberculous mycobacteria (NTMs) cause diseases known as mycobacteriosis and are an important cause of morbidity and mortality. The diagnosis of pulmonary disease caused by NTM is hampered by its clinical similarity with tuberculosis (TB) and by the lack of an accurate and rapid laboratory diagnosis. OBJECTIVES: Detect DNA from NTMs directly from lung samples using real-time polymerase chain reaction (qPCR) for amplification of 16S rRNA. Additionally, DNA sequencing (hsp65 and rpoB genes) was used to identify the species of MNTs. METHODS: A total of 68 sputum samples (54 with suspected NTMs and 14 with TB) from patients treated at a referral hospital were used. FINDINGS: Of these, 27/54 (50%) were qPCR positive for NTMs and 14/14 TB patients (controls) were qPCR negative with an almost perfect concordance (Kappa of 0.93) with the Mycobacterium spp. culture. Sequencing confirmed the presence of NTM in all positive samples. The most common species was Mycobacterium gordonae (33%), followed by Mycobacterium abscessus (26%), Mycobacterium fortuitum (22%), Mycobacterium avium (15%) and Mycobacterium peregrinum (4%). MAIN CONCLUSIONS: The qPCR technique for detecting NTMs targeting 16S rRNA has the potential to detect NTMs and rapidly differentiate from Mycobacterium tuberculosis. However, it is necessary to identify the species to help in the differential diagnosis between disease and contamination, and to guide the choice of the therapeutic scheme.

Chemical Profile and Antimicrobial Activity of the Marine Diatom Chaetoceros muelleri.

Microalgae, due to its rapid growth, low nutritional requirements, and versatility of adaptation to different environmental conditions, has aroused the biotechnological interest, synthesizing novel molecules with antioxidant, anticoagulant, anti-inflammatory, antitumor, and antimicrobial activities. In this sense, we carried out the bioprospection of Chaetoceros muelleri, a marine diatom employed in aquaculture, as a candidate to the development of new drugs for the treatment of bacterial infections. The chemical profile of extracts in different solvents (hexane, chloroform, methylene chloride, ethyl acetate, methanol, and acetone) were analyzed by 1 H-NMR. The hexane extract was the most active against all bacteria species tested, including Mycobacterium tuberculosis, with a minimum inhibitory concentration of 100 µg/ml. Contrarily, the methanol extract was inactive against all tested microorganisms and, in addition, was the only one with IC50 >800 µg/mL, showing no cytotoxicity in VERO cell lines. All other extracts showed antibacterial potential and IC50 values varying between 267.58 and 142.47 µg/ml. The fact that C. muelleri is a microalga easily grown on bioreactors on a large scale may promote its biotechnological use, especially as scaffolds for the development of new compounds against bacterial species of clinical and public health interest.

2,2,2-trifluoro-1-(1,4,5,6-tetrahydropyridin-3-yl)ethanone derivative as efflux pump inhibitor in Mycobacterium tuberculosis.

Although the administration of combined therapy is efficient to tuberculosis (TB) treatment caused by susceptible Mycobacterium tuberculosis strains, to overcome the multidrug resistance is still a challenge. Some studies have reported evidence about tetrahydropyridines as a putative efflux pump inhibitor, including in mycobacteria, being a promising strategy against M. tuberculosis. Thus, we investigated the biological potential of 2,2,2-trifluoro-1-(1,4,5,6-tetrahydropyridin-3-yl)ethanone derivative (NUNL02) against two strains of M. tuberculosis. NUNL02 was able to increase the susceptibility of the multidrug resistant strain to the anti-TB drugs, resulting in synergism with rifampicin. Still, we assume that this compound plays a role in the efflux mechanism in M. tuberculosis, besides, to be able to kill the bacillus under the deprivation of essential nutrients. Thus, our findings highlight NUNL02 as a promising prototype to develop a new adjuvant for TB treatment, mainly as EPI.

Mefloquine synergism with anti-tuberculosis drugs and correlation to membrane effects: Biologic, spectroscopic and molecular dynamics simulations studies.

Studies displaying the combination of mefloquine (MFL) with anti-tuberculosis (TB) substances are limited in the literature. In this work, the effect of MFL-association with two first-line anti-TB drugs and six fluoroquinolones was evaluated against Mycobacterium tuberculosis drug resistant strains. MFL showed synergistic interaction with isoniazid, pyrazinamide, and several fluoroquinolones, reaching fractional inhibitory concentration indexes (FICIs) ranging from 0.03 to 0.5. In order to better understand the observed results, two approaches have been explored: (i) spectroscopic responses attributed to the effect of MFL on physicochemical properties related to a liposomal membrane model composed by soybean asolectin; (ii) molecular dynamics (MD) simulation data regarding MFL interaction with a membrane model based on PIM2, a lipid constituent of the mycobacterial cell wall. FTIR and NMR data showed that MFL affects expressively the region between the phosphate and the first methylene groups of soybean asolectin membranes, disordering these regions. MD simulations results detected high MFL density in the glycolipid interface and showed that the drug increases the membrane lateral diffusion, enhancing its permeability. The obtained results suggest that synergistic activities related to MFL are attributed to its effect of lipid disorder and membrane permeability enhancement.

Novel phage display-derived recombinant antibodies recognizing both MPT64 native and mutant (63-bp deletion) are promising tools for tuberculosis diagnosis.

Tuberculosis (TB) is one of the top 10 causes of death in humans worldwide. The most important causative agents of TB are bacteria from the Mycobacterium tuberculosis complex (MTC), although nontuberculous mycobacteria (NTM) can also cause similar infections. The ability to identify and differentiate MTC isolates from NTM is important for the selection of the correct antimicrobial therapy. Immunochromatographic assays with antibodies anti-MPT64 allow differentiation between MTC and NTM since the MPT64 protein is specific from MTC. However, studies reported false-negative results mainly due to mpt64 63-bp deletion. Considering this drawback, we selected seven human antibody fragments against MPT64 by phage display and produced them as scFv-Fc. Three antibodies reacted with rMPT64 mutant (63-bp deletion) protein and native MPT64 from M. tuberculosis H37Rv in ELISA and Western blot. These antibodies are new biological tools with the potential for the development of TB diagnosis helping to overcome limitations of the MPT64-based immunochromatographic tests currently available.

Tuberculosis caused by Mycobacterium pinnipedii in a wild South American sea lion Otaria flavescens stranded in southern Brazil.

Tuberculosis (TB) in pinnipeds is typically caused by Mycobacterium pinnipedii, which has also been associated with infections in other species, such as cattle and humans. As a result, this pathogen has zoonotic potential and is a public health concern. In 2016, a female South American sea lion Otaria flavescens in southern Brazil presented with emaciation and severe dyspnea and died within 3 h of capture. Gross pathology identified pulmonary granulomas, and Ziehl-Neelsen stain identified acid-fast bacilli. M. tuberculosis complex bacteria were confirmed by a BD BACTEC™ MGIT™ 320 detection system using fibrinous exudate, lung granulomas and thoracic fluid. Molecular characterization by spoligotyping showed a hybridization pattern characteristic of M. pinnipedii (SIT593/PINI1). Currently, there is a paucity of data concerning the transmission and epidemiology of M. pinnipedii in pinniped populations in South America. The case report shows that the disease appeared in a free-ranging beached sea lion on the coast, and further surveillance is needed to determine the origin of this TB because of its potential impact on public health.

Prognostic Significance of The New Criteria for Acute Kidney Injury in Cirrhosis.

BACKGROUND: New criteria for acute kidney injury (AKI) in cirrhosis have been proposed, but its prognostic significance is unclear. This study aims to evaluate the prognostic significance of the AKI criteria in cirrhotic patients hospitalized for acute decompensation. MATERIAL AND METHODS: This is a prospective cohort study. AKI was defined as an increase in creatinine (Cr) levels ≥ 0.3 mg/dL in 48 h or ≥ 50% of the basal value in the last 7d. AKI was divided into stages 1 (elevation: < 2x basal), 2 (2 or 3x), and 3 (> 3x). RESULTS: In this study, 227 patients aged 53.9 ± 11.5 years were included, of whom 37% had AKI (28% AKI1, 5% AKI2, and 4% AKI3). Thirty percent of the patients died or were transplanted within 90 days from causes related to the presence of ascites at hospital admission and higher values of Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) scores, but not to the presence of AKI. In a regression analysis conducted to assess the effect of the final Cr level in patients with AKI, 90-day mortality was associated with ascites, higher CLIF-SOFA score, and AKI with final Cr level ≥ 1.5 mg/dL. The patients with AKI with Cr levels ≥ 1.5 mg/dL showed lower transplant-free survival rates than those without AKI, and those with AKI1 with final Cr level < 1.5 mg/dL. CONCLUSIONS: Early AKI was frequent and associated with 90-day mortality or transplantation only when the final Cr level was ≥ 1.5 mg/dL. Distinct approaches are needed for patients with AKI1 according to final Cr.

From stable disease to acute-on-chronic liver failure: Circulating cytokines are related to prognosis in different stages of cirrhosis.

INTRODUCTION: Although both pro- and anti-inflammatory circulating cytokines are known to be elevated in liver cirrhosis, its clinical significance is not completely recognized. Our aim was to evaluate the prognostic significance of circulating cytokines interleukin (IL)-6, IL-17 and IL-10 in different stages of cirrhosis. METHODS: This prospective study included two cohorts: (1) stable cirrhosis attended in the Outpatient Clinic (n=118), and (2) subjects hospitalized for acute decompensation (AD) (n=130). Thirty healthy subjects served as control group. RESULTS: Patients with cirrhosis exhibited higher levels of cytokines as compared to controls. In stable cirrhosis, during a median follow-up of 17months, liver-related events occurred in 26 patients. Higher IL-10 levels and Child-Pugh B/C were independently associated with reduced event-free survival. In AD cohort, death after 90days of follow-up occurred in 39 patients and was independently associated with ascites, higher IL-6 and model for end-stage liver disease. IL-6 levels also showed higher AUROC than CRP for predicting bacterial infection in the AD cohort (0.831±0.043vs. 0.763±0.048, respectively). IL-17 decreased at third day of hospitalization only in patients who progressed to death. Higher IL-6 levels were observed in acute-on-chronic liver failure (ACLF) patients even in the absence of bacterial infection whereas IL-10 was higher only in subjects with infection-related ACLF. Higher IL-10 and IL-17 levels were associated with progression to death in ACLF. CONCLUSIONS: The pattern of immune response seems to vary according to the phase of cirrhosis and is related to prognosis, from stable disease to ACLF.

Prognostic significance of insulin-like growth factor-I serum levels in acute decompensation of cirrhosis.

CONTEXT: IGF-I serum levels are suppressed in cirrhosis, but its prognostic significance is unknown. OBJECTIVES: To investigate the prognostic value of IGF-I in patients admitted for acute decompensation of cirrhosis. MATERIALS AND METHODS: Cohort study that included 103 patients. IGF-I was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Ninety-day mortality was 26.2% and it was independently associated with MELD, age and IGF-I. The Kaplan-Meier survival probability at 90 days was 94.3% in patients with IGF-I ≥13 ng/mL and 63.2% for patients with IGF-I <13 ng/mL (p = .001). DISCUSSION AND CONCLUSION: IGF-I levels are independently associated with mortality in acute decompensation of cirrhosis.

Toxocara canis: Larvicidal activity of fatty acid amides.

Considering the therapeutic potential of fatty acid amides, the present study aimed to evaluate their in vitro activity against Toxocara canis larvae and their cytotoxicity for the first time. Linoleylpyrrolidilamide was the most potent, with a minimal larvicidal concentration (MLC) of 0.05 mg/mL and 27% cytotoxicity against murine peritoneal macrophages C57BL/6 mice, as assessed by the MTT assay.

Coastal natural products: a review applied to antimycobacterial activity.

Despite the many advances in drug research, natural products are still being explored as a promising source for discovering new bioactive compounds to treat global diseases such as tuberculosis. However, there is a lack of studies and information about coastal natural products, which thrive in the transitional environment between two different ecosystems and produce unique secondary metabolites. Mangroves, estuaries, and mudflats make up areas for coastal species and have shown promising results in antituberculosis research, some of them are present in hotspot areas. This review focuses on research conducted in coastal environments and explores the reasons why these natural products tend to outperform non-coastal ones against the causative agent of tuberculosis, Mycobacterium tuberculosis.

Detection of Mtb and NTM: preclinical validation of a new asymmetric PCR-binary deoxyribozyme sensor assay.

Tuberculosis (TB) and infectious diseases caused by non-tuberculous mycobacteria (NTM) are global concerns. The development of a rapid and accurate diagnostic method, capable of detecting and identifying different mycobacteria species, is crucial. We propose a molecular approach, the BiDz-TB/NTM, based on the use of binary deoxyribozyme (BiDz) sensors for the detection of Mycobacterium tuberculosis (Mtb) and NTM of clinical interest. A panel of DNA samples was used to evaluate Mtb-BiDz, Mycobacterium abscessus/Mycobacterium chelonae-BiDz, Mycobacterium avium-BiDz, Mycobacterium intracellulare/Mycobacterium chimaera-BiDz, and Mycobacterium kansasii-BiDz sensors in terms of specificity, sensitivity, accuracy, and limit of detection. The BiDz sensors were designed to hybridize specifically with the genetic signatures of the target species. To obtain the BiDz sensor targets, amplification of a fragment containing the hypervariable region 2 of the 16S rRNA was performed, under asymmetric PCR conditions using the reverse primer designed based on linear-after-the-exponential principles. The BiDz-TB/NTM was able to correctly identify 99.6% of the samples, with 100% sensitivity and 0.99 accuracy. The individual values of specificity, sensitivity, and accuracy, obtained for each BiDz sensor, satisfied the recommendations for new diagnostic methods, with sensitivity of 100%, specificity and accuracy ranging from 98% to 100% and from 0.98 to 1.0, respectively. The limit of detection of BiDz sensors ranged from 12 genome copies (Mtb-BiDz) to 2,110 genome copies (Mkan-BiDz). The BiDz-TB/NTM platform would be able to generate results rapidly, allowing the implementation of the appropriate therapeutic regimen and, consequently, the reduction of morbidity and mortality of patients.IMPORTANCEThis article describes the development and evaluation of a new molecular platform for accurate, sensitive, and specific detection and identification of Mycobacterium tuberculosis and other mycobacteria of clinical importance. Based on BiDz sensor technology, this assay prototype is amenable to implementation at the point of care. Our data demonstrate the feasibility of combining the species specificity of BiDz sensors with the sensitivity afforded by asymmetric PCR amplification of target sequences. Preclinical validation of this assay on a large panel of clinical samples supports the further development of this diagnostic tool for the molecular detection of pathogenic mycobacteria.

Binding Evolution of the Dengue Virus Envelope Against DC-SIGN: A Combined Approach of Phylogenetics and Molecular Dynamics Analyses Over 30 Years of Dengue Virus in Brazil.

The Red Queen Hypothesis (RQH), derived from Lewis Carroll's "Through the Looking-Glass", postulates that organisms must continually adapt in response to each other to maintain relative fitness. Within the context of host-pathogen interactions, the RQH implies an evolutionary arms race, wherein viruses evolve to exploit hosts and hosts evolve to resist viral invasion. This study delves into the dynamics of the RQH in the context of virus-cell interactions, specifically focusing on virus receptors and cell receptors. We observed multiple virus-host systems and noted patterns of co-evolution. As viruses evolved receptor-binding proteins to effectively engage with cell receptors, cells countered by altering their receptor genes. This ongoing mutual adaptation cycle has influenced the molecular intricacies of receptor-ligand interactions. Our data supports the RQH as a driving force behind the diversification and specialization of both viral and host cell receptors. Understanding this co-evolutionary dance offers insights into the unpredictability of emerging viral diseases and potential therapeutic interventions. Future research is crucial to dissect the nuanced molecular changes and the broader ecological consequences of this ever-evolving battle. Here, we combine phylogenetic inferences, structural modeling, and molecular dynamics analyses to describe the epidemiological characteristics of major Brazilian DENV strains that circulated from 1990 to 2022 from a combined perspective, thus providing us with a more detailed picture on the dynamics of such interactions over time.

Inhaled corticosteroids increase the risk of oropharyngeal colonization by Streptococcus pneumoniae in children with asthma.

BACKGROUND AND OBJECTIVE: Recent studies have raised concerns about the link between use of inhaled corticosteroids (ICS) and risk of pneumonia in patients with chronic obstructive pulmonary disease. This cross-sectional study aimed to investigate the association between ICS and oropharyngeal colonization by Streptococcus pneumoniae (S. pneumoniae) among children (up to 18 years old) with asthma. METHODS: Two age-matched groups of patients were consecutively recruited: (i) exposed group: children who had persistent asthma and were being treated with daily ICS for at least 30 days and (ii) non-exposed group: children who had asthma and were not being treated with ICS at study entry. Oropharyngeal specimens from the tonsillar area and posterior pharyngeal wall were collected. S. pneumoniae was identified according to National Committee for Clinical Laboratory Standards recommendations. RESULTS: A total of 200 consecutive patients were recruited and 192 (96 in each group) were included in the analysis. In the exposed group, the mean daily dose of ICS was 400 µg of beclomethasone or equivalent and the mean duration of treatment was 8.6 months. The prevalence of oropharyngeal colonization by S. pneumoniae was higher in the exposed group compared with the non-exposed group (27.1% vs 8.3%, P = 0.001). After adjusting for potential confounders, use of ICS was an independent risk factor for oropharyngeal carriage of S. pneumoniae, with an adjusted prevalence ratio of 3.75 (95% confidence interval: 1.72-8.18, P = 0.001). CONCLUSIONS: Regular use of ICS is associated with an increased risk of having oropharyngeal colonization by S. pneumoniae in children with asthma.

Genotyping methods and their contributions to the study of tuberculosis dynamic in Latin America.

INTRODUCTION: Mycobacterium tuberculosis genotyping has impacted evolutionary studies worldwide. Nonetheless, its application and the knowledge generated depend on the genetic marker evaluated and the detection technologies that have evolved over the years. Here we describe the timeline of main genotypic methods related to M. tuberculosis in Latin America and the main findings obtained. METHODOLOGY: Systematic searches through the PubMed database were performed from 1993 to May 2021. A total of 345 articles met the inclusion criteria and were selected. RESULTS: Spacer oligonucleotide typing (spoligotyping) was the most widely used method in Latin America, with decreasing use in parallel with increasing use of mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) and whole genome sequencing (WGS). Among the countries, Brazil, Mexico, and Argentina had the most publications, and a considerable part of the articles were in collaboration with Latin American or non-Latin American institutions; a small proportion of studies needed partnerships to perform the genotypic methods. The genotypic methods allowed the identification of M. tuberculosis genotypes with greater capacity for clonal expansion and revealed the predominance of the Euro-American lineage in Latin America. There was a notable presence of the Beijing family in Peru and Colombia. CONCLUSIONS: The data obtained demonstrated the importance of expanding collaborative networks of tuberculosis (TB) research groups to countries with low productivity in this area, the commitment of the few Latin American countries to advance TB research, as well as the inestimable value of building a Latin America database, considering ease of population mobility between countries.

Evaluation of the immunosuppressive effect of cyclophosphamide and dexamethasone in mice with visceral toxocariasis.

Visceral toxocariasis is a serious public health problem with a cosmopolitan distribution. Children are susceptible due to their immature immune system and high risks of infection. Nevertheless, the few completed studies about immunosuppression have had controversial results. To evaluate the effect of two immunosuppressive drugs on the larval burden of Toxocara canis, four groups of ten Swiss strain mice each were inoculated on day 0 with 1,200 embryonated T. canis eggs. Fifteen days before the experimental infection, group 1 (control) was treated via intraperitoneal injection (IP) with sterile distilled water and groups 2 and 3 were treated with dexamethasone (DEX) at 1 and 5 mg/kg/day, respectively. Additionally, group 4 was treated IP with cyclophosphamide (CY) at 50 mg/kg at two times per week for 2 weeks. Sixty days following infection, the mice were euthanised to recover the larvae by means of the tissue digestion technique. The levels of antibodies detected by indirect ELISA were not associated with the larval burden. Administration of CY (50 mg/kg) and DEX (5 mg/kg) resulted in an increase of the larval burden of 162.1% and 50.8%, respectively, in relation to the control group. These two treatments, especially CY (50 mg/kg), promoted immunosuppression and the establishment of a significant larval burden, supporting its further utilisation in studies related to immunosuppression in visceral toxocariasis.

Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis.

We validated the nitrate reductase assay (NRA) for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) using sodium nitrate (NaNO3) in replacement of potassium nitrate (KNO3) as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB.