Profiles of suicide attempted in children and adolescents.

OBJECTIVE: Suicide attempt (SA) is the strongest predictive variable for completed suicide. The Department of Cauca in Colombia has an SA rate higher than the national average, but the factors are unknown. The objective was to identify the profiles of SA in children and adolescents of Cauca. METHODS: Cross-sectional study, which included all SA (Event-356) records from the SIVIGILA platform in children under 18 years of age between 2016 and 2019. The authors described the variables and multiple correspondence analysis with the Burt method, according to the completeness of the data to establish the possible SA profiles using STATA 15.1, and R. The Ethics Committee at Universidad del Cauca approved it. RESULTS: The study found 977 SA during this period, 72.4% female, 97.1% adolescent, 74.4% mestizo, 19.3% indigenous, 45.3% resided in municipalities exposed to the armed conflict, 32.3% expressed ideation and previous attempts, and 15.5% prior attempts. The MCA included 810 SA and identified three profiles: "Classic", which had mestizo adolescents with a history of prior SA, mental illness, or psychoactive substance use problems; "Related to the armed conflict", which included female adolescents with a first SA and residents in municipalities exposed to the armed conflict; "Ethnic" represented by male indigenous, with housing in a rural area. CONCLUSION: The SA profiles found in Cauca were "Classic", "Related to the armed conflict", and "Ethnic"; these can be considered to implement prevention strategies from a cross-cultural, mental health, and gender perspective, with the presence of the state in the territories.

In vitro activity of ceftazidime-avibactam against gram-negative bacteria in patients with bacteremia and skin and soft-tissue infections in Colombia 2019-2021.

OBJECTIVES: Ceftazidime-avibactam (CAZ-AVI) is an option for infections caused by MDR gram-negative bacilli. In this study, we aimed to analyze the in vitro antimicrobial activity of CAZ-AVI and other antimicrobial agents against gram-negative bacilli that were collected in Colombia between 2019 and 2021 from patients with bacteremia and skin and soft-tissue infections (SSTIs). METHODS: A total of 600 Enterobacterales and 259 P. aeruginosa strains were analyzed. The phenotypic resistance of isolates, particularly non-susceptibility to meropenem, multidrug-resistant (MDR) isolates, and difficult-to-treat (DTR) P. aeruginosa, was evaluated according to CLSI breakpoints. RESULTS: Enterobacterales had the most susceptibility to CAZ-AVI (96.5 %) and tigecycline (95 %). Tigecycline and CAZ-AVI were the antimicrobial agents with the most in vitro activity against carbapenem-resistant Enterobacterales (CRE). CAZ-AVI was the antimicrobial treatment with the most activity against P. aeruginosa. CONCLUSIONS: Tigecycline and CAZ-AVI were the antimicrobial agents with the most activity against CRE and MDR Enterobacterales. For P. aeruginosa, CAZ-AVI was the antimicrobial treatment with the most in vitro activity.

Correlation between breast cancer subtypes determined by immunohistochemistry and n-COUNTER PAM50 assay: a real-world study.

PURPOSE: Molecular subtyping based on gene expression profiling (i.e., PAM50 assay) aids in determining the prognosis and treatment of breast cancer (BC), particularly in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, where luminal A and B subtypes have different prognoses and treatments. Several surrogate classifications have been proposed for distinguishing between the luminal A and B subtypes. This study determines the accuracy of local immunohistochemistry (IHC) techniques for classifying HR-positive/HER2-negative (HR+/HER2-) tumors according to intrinsic subtypes using the nCOUNTER PAM50 assay as reference and the HR status definition according the ASCO/CAP recommendations. METHODS: Molecular subtypes resulting from nCOUNTER PAM50 performed in our laboratory between 2014 and 2020 were correlated with three different proxy surrogates proposed in the literature based on ER, PR, HER2, and Ki67 expression with different cut-off values. Concordance was measured using the level of agreement and kappa statistics. RESULTS: From 1049 samples with the nCOUNTER test, 679 and 350 were luminal A and B subtypes, respectively. Only a poor-to-fair correlation was observed between the three proxy surrogates and real genomic subtypes as determined by nCOUNTER PAM50. Moreover, 5-11% and 18-36% of the nCOUNTER PAM50 luminal B and A tumors were classified as luminal A and B, respectively, by these surrogates. CONCLUSION: The concordance between luminal subtypes determined by three different IHC-based classifiers and the nCOUNTER PAM50 assay was suboptimal. Thus, a significant proportion of luminal A and B tumors as determined by the surrogate classifiers could be undertreated or over-treated.

Optimizing biodegradable plastics: Molecular dynamics insights into starch plasticization with glycerol and oleic acid.

Petroleum-based plastics dominate everyday life, necessitating the exploration of natural polymers as alternatives. Starch, abundant and biodegradable, is a promising raw material. However, understanding the molecular mechanisms underlying starch plasticization has proven challenging. To address this, we employ molecular dynamics simulations, focusing on amylose as a model. Our comprehensive evaluation revealed that chain size affects solubility, temperature influenced diffusivity and elastic properties, and oleic acid expressed potential as an alternative plasticizer. Furthermore, blending glycerol or oleic acid with water suggested the enhancement amylose's elasticity. These findings contribute to the design of sustainable and improved biodegradable plastics.

Fundamento y generalidades de la construcción de modelos estadísticos multinivel en el ámbito de la investigación en salud

Este trabajo tiene como objetivo presentar una mirada global de la aplicabilidad de los modelos de análisis multinivel en el ámbito de la investigación sanitaria. Ofrece información sobre los fundamentos teóricos, metodológicos y estadísticos y, además, menciona los pasos básicos para la construcción de estos modelos, y da ejemplos de su uso, según la estructura jerárquica de los datos. Cabe resaltar que, antes de utilizar estos modelos, se requiere contar con un soporte teórico sobre la necesidad de uso y una valoración estadística que dé cuenta del porcentaje de varianza explicada por el efecto de agrupación de las observaciones. Los requisitos para llevar a cabo este tipo de análisis dependen de condiciones especiales como el tipo de variables, la cantidad de unidades por nivel o el tipo de estructura jerárquica. Se concluye que los modelos de análisis multinivel son una herramienta útil para lograr la integración de información, dadas la complejidad de las relaciones y las interacciones que determinan la mayoría de las condiciones de salud, incluida la pérdida de independencia entre las unidades de observación.

This topic review aims to present a global vision of multilevel analysis models' applicability to health research, explaining its theoretical, methodological, and statistical foundations. We describe the basic steps to build these models and examples of their application according to the data hierarchical structure. It ir worth noticing that before using these models, researchers must have a rationale for needing them, and a statistical evaluation accounting for the variance percentage explained by the observations grouping effect. The requirements to conduct this type of analysis depends on special conditions such as the type of variables, the number of units per level, or the type of hierarchical structure. We conclude that multilevel analysis models are a useful tool to integrate information, considering the complexity of the relationships and interactions involved in most health conditions, including the loss of independence between observation units.

Infiltrating Lobular Carcinoma of the Breast Metastatic to the Duodenum, about a Case

Introduction: Gastric outlet obstruction or pyloric syndrome can occur secondary to neoplastic involvement, and metastasis as an etiology is unusual. Breast neoplasms generally cause bone, liver, and lung metastases, rarely involving the gastrointestinal tract. Case presentation: A 69-year-old female patient with infiltrating lobular carcinoma of the right breast consulted for abdominal pain and postprandial emetic episodes with oral intolerance and dyspnea. Bilateral neoplastic breast involvement and dilation of the gastric chamber with thickening of the pylorus were recorded. She required antiemetic management and placement of a nasogastric tube. She was taken to an upper digestive tract endoscopy, which found an ulcerated lesion with an infiltrative appearance at the postpyloric level that circumferentially compromised the duodenal lumen. Then, a biopsy was taken, which was compatible with a breast carcinoma of a lobular type. This entity, called pyloric syndrome due to neoplasia, can be managed with gastrojejunostomy or an enteral prosthesis that improves the quality of life of patients with an ominous short-term prognosis. The patient in our case expressed advance directives not to receive invasive procedures, for which an uncovered metal prosthesis was placed for palliative purposes, achieving the re-establishment of the feeding route and resolution of dyspnea due to restriction. Conclusions: The metastatic involvement of neoplasms of the breast to the gastrointestinal tract is rare; however, it should be suspected in elderly patients with previously documented neoplasms.

Introducción: La obstrucción al tracto de salida gástrico o síndrome pilórico puede presentarse de manera secundaria a compromiso neoplásico, y es inusual el compromiso metastásico como etiología. Las neoplasias de la mama generalmente originan metástasis óseas, hepáticas y pulmonares, y es infrecuente el compromiso del tracto digestivo. Presentación del caso: Se trata de una paciente de 69 años con carcinoma lobulillar infiltrante de mama derecha que consultó por dolor abdominal y episodios eméticos posprandiales con intolerancia a la vía oral y disnea. Se registró un compromiso neoplásico mamario bilateral y dilatación de la cámara gástrica con engrosamiento del píloro. Se dio manejo antiemético y colocación de sonda nasogástrica. Fue llevada a una endoscopia de vías digestivas altas en la que se encontró una lesión ulcerada de aspecto infiltrativo a nivel pospilórico que comprometía de forma circunferencial la luz duodenal, y luego se tomó una biopsia a este nivel, que fue compatible con un carcinoma mamario de tipo lobulillar. Esta entidad, denominada síndrome pilórico por neoplasias, puede manejarse con gastroyeyunostomía o con prótesis enteral que mejore la calidad de vida en pacientes con pronóstico ominoso a corto plazo. La paciente de nuestro caso manifestó voluntades anticipadas para no recibir procedimientos invasivos, por lo cual se ofreció la colocación de una prótesis metálica descubierta con fines paliativos y se logró el restablecimiento de la vía de alimentación y resolución de la disnea por restricción. Conclusiones: El compromiso metastásico de neoplasias de la mama al tracto digestivo es poco frecuente; sin embargo, debe sospecharse en pacientes de edad avanzada y con neoplasias previamente documentadas.

Construction of multilevel statistical models in health research: Foundations and generalities / Fundamento y generalidades de la construcción de modelos estadísticos multinivel en el ámbito de la investigación en salud

This topic review aims to present a global vision of multilevel analysis models' applicability to health research, explaining its theoretical, methodological, and statistical foundations. We describe the basic steps to build these models and examples of their application according to the data hierarchical structure. It ir worth noticing that before using these models, researchers must have a rationale for needing them, and a statistical evaluation accounting for the variance percentage explained by the observations grouping effect. The requirements to conduct this type of analysis depends on special conditions such as the type of variables, the number of units per level, or the type of hierarchical structure. We conclude that multilevel analysis models are a useful tool to integrate information, considering the complexity of the relationships and interactions involved in most health conditions, including the loss of independence between observation units.

Este trabajo tiene como objetivo presentar una mirada global de la aplicabilidad de los modelos de análisis multinivel en el ámbito de la investigación sanitaria. Ofrece información sobre los fundamentos teóricos, metodológicos y estadísticos y, además, menciona los pasos básicos para la construcción de estos modelos, y da ejemplos de su uso, según la estructura jerárquica de los datos. Cabe resaltar que, antes de utilizar estos modelos, se requiere contar con un soporte teórico sobre la necesidad de uso y una valoración estadística que dé cuenta del porcentaje de varianza explicada por el efecto de agrupación de las observaciones. Los requisitos para llevar a cabo este tipo de análisis dependen de condiciones especiales como el tipo de variables, la cantidad de unidades por nivel o el tipo de estructura jerárquica. Se concluye que los modelos de análisis multinivel son una herramienta útil para lograr la integración de información, dadas la complejidad de las relaciones y las interacciones que determinan la mayoría de las condiciones de salud, incluida la pérdida de independencia entre las unidades de observación.

International Comparison, Risk Assessment, and Prioritisation of 26 Endocrine Disrupting Compounds in Three European River Catchments in the UK, Ireland, and Spain.

Endocrine-disrupting compounds (EDCs) constitute a wide variety of chemistries with diverse properties that may/can pose risks to both humans and the environment. Herein, a total of 26 compounds, including steroids, flame retardants, and plasticizers, were monitored in three major and heavily urbanized river catchments: the R. Liffey (Ireland), the R. Thames (UK), and the R. Ter (Spain), by using a single solid-phase extraction liquid chromatography-mass spectrometry (SPE-LC-MS/MS) method. Occurrence and frequency rates were investigated across all locations over a 10-week period, with the highest concentration obtained for the flame retardant tris(2-chloroethyl) phosphate (TCEP) at 4767 ng∙L-1 in the R. Thames in Central London. Geographical variations were observed between sites and were partially explained using principal component analysis (PCA) and hierarchical cluster analysis (HCA). In particular, discrimination between the R. Ter and the R. Thames was observed based on the presence and concentration of flame retardants, benzotriazole, and steroids. Environmental risk assessment (ERA) across sites showed that caffeine, a chemical marker, and bisphenol A (BPA), a plasticizer, were classified as high-risk for the R. Liffey and R. Thames, based on relative risk quotients (rRQs), and that caffeine was classified as high-risk for the R. Ter, based on RQs. The total risks at each location, namely ΣRQriver, and ΣrRQriver, were: 361, 455, and 723 for the rivers Liffey, Thames, and Ter, respectively. Caffeine, as expected, was ubiquitous in all 3 urban areas, though with the highest RQ observed in the R. Ter. High contributions of BPA were also observed across the three matrices. Therefore, these two compounds should be prioritized independently of location. This study represents a comprehensive EDC monitoring comparison between different European cities based on a single analytical method, which allowed for a geographically independent ERA prioritization to be performed.

Synergistic effect of electrotrophic perchlorate reducing microorganisms and chemically modified electrodes for enhancing bioelectrochemical perchlorate removal.

Perchlorate has been described as an emerging pollutant that compromises water sources and human health. In this study, a new electrotrophic perchlorate reducing microorganism (EPRM) isolated from the Atacama Desert, Dechloromonas sp. CS-1, was evaluated for perchlorate removal in water in a bioelectrochemical reactor (BER) with a chemically modified electrode. BERs were operated for 17 days under batch mode conditions with an applied potential of -500 mV vs. Ag/AgCl. Surface analysis (i.e., SEM, XPS, FT-IR, RAMAN spectroscopy) on the modified electrode demonstrated heterogeneous transformation of the carbon fibers with the incorporation of nitrogen functional groups and the oxidation of the carbonaceous material. The BERs with the modified electrode and the presence of the EAM reached high cathodic efficiency (90.79 ± 9.157%) and removal rate (0.34 ± 0.007 mol m-3-day) compared with both control conditions. The observed catalytic enhancement of CS-1 was confirmed by a reduction in the charge transfer resistance obtained by electrochemical impedance spectroscopy (EIS). Finally, an electrochemical kinetic study revealed an eight-electron perchlorate bioreduction reaction at -638.33 ± 24.132 mV vs. Ag/AgCl. Therefore, our results show the synergistic effect of EPRM and chemically modified electrodes on perchlorate removal in a BER.

Prediction of serious complications in patients with pulmonary thromboembolism and solid cancer: Validation of the EPIPHANY Index in a prospective cohort of patients from the PERSEO study.

INTRODUCTION: There is currently no validated score capable of classifying cancer-associated pulmonary embolism (PE) in its full spectrum of severity. This study has validated the EPIPHANY Index, a new tool to predict serious complications in cancer patients with suspected or unsuspected PE. METHOD: The PERSEO Study prospectively recruited individuals with PE and active cancer or receiving antineoplastic therapy from 22 Spanish hospitals. The estimation of the relative frequency θ of complications based on the EPIPHANY Index categories was made using the Bayesian alternative for the binomial test. RESULTS: A total of 900 patients, who were diagnosed with PE between October 2017 and January 2020, were enrolled. The rate of serious complications at 15 days was 11.8%, 95% highest density interval [HDI], 9.8-14.1%. Of the EPIPHANY low-risk patients, 2.4% (95% HDI, 0.8-4.6%) had serious complications, as did 5.5% (95% HDI, 2.9-8.7%) of the moderate-risk participants and 21.0% (95% HDI, 17.0-24.0%) of those with high-risk episodes. The EPIPHANY Index was associated with overall survival (OS) in patients with different risk levels: median OS was 16.5, 14.4, and 4.4 months for those at low, intermediate, and high risk, respectively. Both the EPIPHANY Index and the Hestia criteria exhibited greater negative predictive value and a lower negative likelihood ratio than the remaining models. The incidence of bleeding at 6 months was 6.2% (95% HDI, 2.9-9.5%) in low/moderate-risk vs 12.7% (95% HDI, 10.1-15.4%) in high-risk (p-value = 0.037) episodes. Of the outpatients, serious complications at 15 days were recorded in 2.1% (95% HDI, 0.7-4.0%) of the cases with EPIPHANY low/intermediate-risk vs 5.3% (95% HDI, 1.7-11.8%) in high-risk cases. CONCLUSION: We have validated the EPIPHANY Index in patients with incidental or symptomatic cancer-related PE. This model can contribute to standardize decision-making in a scenario lacking quality evidence.

The subjective perception of the happiness of older adult residents in Colombia.

Introduction: Happiness is understood as the perception of subjective well-being, it can be a quality, a result, or a state characterized by well-being or satisfaction that every person wants to achieve. In older adults, this satisfaction is a sum of lifelong achievements and triumphs; However, some factors influence this ideal. Objective: Analyze demographic, family, social, personal, and health factors associated with the subjective perception of happiness in older adults, using data from a study conducted in five cities in Colombia, in order to make a theoretical contribution in the search for improvement of their physical, mental and social health. Materials and methods: A quantitative, cross-sectional, analytical study was carried out, using primary source information, obtained with 2,506 surveys from voluntary participants aged 60 and over, who had no cognitive impairment, and who reside in urban areas but not in long-term centers. The variable happiness (classified as high or moderate/low) was used for: (1) A univariate explorative characterization of older adult, (2) a bivariate estimation of the relationships with the factors studied, and (3) a multivariate construction of profiles through multiple correspondences. Results: 67.2% reported high happiness levels, with differences by city: Bucaramanga (81.6%), Pereira (74.7%), Santa Marta (67.4), Medellín (64%), and Pereira (48.7%). Happiness was explained by the absence of risk of depression and little hopelessness, strengthened psychological well-being, a perception of high quality of life, and living in a functional family. Conclusion: This study provided an overview of possible factors that can be enhanced and strengthened with public policies (structural determinant), community empowerment, family strengthening (intermediate determinant), and educational programs (proximal determinant). These aspects are included in the essential functions of public health, in favor of mental and social health in older adults.

Severe COVID-19 Infection during Pregnancy Requiring ECMO: Case Report and Review of the Literature.

BACKGROUND: The risk of developing severe COVID-19 that requires admission to an intensive care unit (ICU) and invasive ventilation is increased in pregnant women. Extracorporeal membrane oxygenation (ECMO) has been successfully used to manage critical pregnant and peripartum patients. CASE REPORT: A 40-year-old patient, unvaccinated for COVID-19, presented to a tertiary hospital in January 2021 at 23 weeks of gestation due to respiratory distress, cough, and fever. The patient had a confirmed diagnosis of SARS-CoV-2 with a PCR test in a private center 48 h before. She required admission into the ICU due to respiratory failure. High-flow nasal oxygen therapy, intermittent noninvasive mechanical ventilation (BiPAP), mechanical ventilation, prone positioning, and nitric oxide therapy were administered. Additionally, hypoxemic respiratory failure was diagnosed. Thus, circulatory assistance using ECMO with venovenous access was performed. After 33 days of ICU admission, the patient was transferred to the internal medicine department. She was discharged 45 days after hospital admission. At 37 weeks of gestation, the patient presented active labor and underwent an uneventful vaginal delivery. CONCLUSIONS: Severe COVID-19 in pregnancy may lead to the requirement for ECMO administration. This therapy should be administered in specialized hospitals using a multidisciplinary approach. COVID-19 vaccination should be strongly recommended to pregnant women to decrease the risk of severe COVID-19.

One-year efficacy and safety of naloxegol on symptoms and quality of life related to opioid-induced constipation in patients with cancer: KYONAL study.

OBJECTIVES: Naloxegol is a peripherally acting µ-opioid receptor antagonist (PAMORA) for treatment of opioid-induced constipation (OIC). The main objective was to analyse the long-term efficacy, quality of life (QOL) and safety of naloxegol in patients with cancer in a real-world study. METHODS: This one-year prospective study included patients older than 18 years, with active oncological disease who were under treatment with opioids for pain control and Karnofsky≥50 and OIC with inadequate response to treatment with laxative (s). All the patients received treatment with naloxegol according to clinical criteria. The main efficacy objectives were measured by the patient assessment of constipation QOL questionnaire (PAC-QOL), the PAC symptoms (PAC-SYM), the response rate at day 15, and months 1-3-6-12, and global QOL (EuroQoL-5D-5L). RESULTS: A total of 126 patients (58.7% males) with a mean age of 61.5 years (95% CI 59.4 to 63.7) were included. PAC-SYM and PAC-QOL total score and all their dimensions improved from baseline (p<0.0001). At 12 months, 77.8% of the patients were responders to naloxegol treatment. Global QOL was conserved from baseline. A total of 28 adverse reactions, mainly gastrointestinal were observed in 15.1% of the patients (19/126), being 75% (21) mild, 17.9% (5) moderate and 7.1% (2) severe. Most adverse reactions (67.9%) appeared the first 15 days of treatment. CONCLUSION: The results of this first long-term and real-world-data study in patients with cancer, showed the sustained efficacy and safety of naloxegol for the treatment of OIC in this group of patients.

Effects of sulfamethoxazole exposure on mussels (Mytilus galloprovincialis) metabolome using retrospective non-target high-resolution mass spectrometry and chemometric tools.

In this work, the Regions of Interest-Multivariate Curve Resolution (ROIMCR) method is proposed for the analysis of non-target metabolomics data. Samples from marine mussels (Mytilus galloprovincialis) exposed to a sublethal concentration (10 µg/L) of sulfamethoxazole (SMX) during 4 days in different seasonal conditions (summer and winter) were analyzed by High-Performance Liquid Chromatography - High-Resolution Mass Spectrometry (HPLC-HRMS) to study the effect of their exposure to SMX and the different seasonal conditions. The Regions of Interest (ROI) procedure has been applied for data filtering, compression, preprocessing and storage steps. Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) is then applied to the previously MS ROI preprocessed data sets to resolve the elution profiles and spectral fingerprints of the chemical constituents of the analyzed samples. The peak areas of the elution profiles of the chemical constituents resolved by the combined ROIMCR procedure were analyzed by Principal Component Analysis (PCA) and samples were clustered according to their experimental seasonal and SMX exposure. The effects of the two investigated factors and of their interaction on the concentrations of the metabolites were statistically assessed by ANOVA simultaneous component analysis (ASCA). Both types of analyses, PCA clustering and ASCA, confirmed that the seasonal conditions (summer versus winter) produced larger effects than those produced by the exposure to SMX and by the interaction of these two factors. The concentration changes of 16 identified endogenous metabolites were validated individually using a Wilcoxon statistical test, which confirmed the presence of significant disturbances in the levels of some of these metabolites (free fatty acids, amino acids and nucleic acids), and indicated the possible alteration of six different biological pathways, affected by the investigated seasonal and SMX exposure factors.

The loads developed by epicondylar and epitrochlear muscles across the elbow joint. A dynamic simulated model.

The radio-humeral joint has traditionally been believed to support most of the loads transmitted through the elbow. Load transfer through the elbow has been a controversial issue since the publication of the first biomechanical studies on the subject, most of which were based on extrinsic forces acting on the extended joint. The present study analyzes load distribution across the six different compartments in the elbow while the joint is flexed, as well as the intrinsic forces generated in the epicondylar and epitrochlear muscles. Ten cadaveric elbows were positioned at 90° of flexion, forearm in a neutral position and wrist at 0°. Tekscan sensors were used for measuring intraarticular pressures. Forces generated by epitrochlear muscles results in a series of loads that affect mainly the anteromedial facet (40%), followed by the posterolateral facet (34%) of the ulnohumeral joint, with the flexor carpi ulnaris generating the heaviest loads (43% on the anteromedial and 38% on the posterolateral facets). Conversely, the forces generated by the epicondylar muscles, similar in behavior but with an opposite direction, convey heavier loads to the elbow's anterolateral facet (45%), followed by the radiohumeral joint (26%) with the extensor carpi ulnaris generating the heaviest loads (54% on the anterolateral facet and 17% on the radiohumeral joint). Our results indicate that the elbow joint exhibits a characteristic load distribution pattern that depends on the muscles, as intrinsic forces are generated by the epicondylar and epitrochlear muscles. The anterior portion of the ulnohumeral joint is the area bearing the heaviest loads.

Enhanced nitrogen and carbon removal in natural seawater by electrochemical enrichment in a bioelectrochemical reactor.

Municipal and industrial wastewater discharges in coastal and marine environments are of major concern due to their high carbon and nitrogen loads and the resulted phenomenon of eutrophication. Bioelectrochemical reactors (BERs) for simultaneous nitrogen and carbon removal have gained attention owing to their cost efficiency and versatility, as well as the possibility of electrochemical enrich specific groups. This study presented a scalable two-chamber BERs using graphite granules as electrode material. BERs were inoculated and operated for 37 days using natural seawater with high concentrations of ammonium and acetate. The BERs demonstrated a maximum current density of 0.9 A m-3 and removal rates of 7.5 mg NH4+-N L-1 d-1 and 99.5 mg L-1 d-1 for total organic carbon (TOC). Removals observed for NH4+-N and TOC were 96.2% and 68.7%, respectively. The results of nutrient removal (i.e., ammonium, nitrate, nitrite and TOC) and microbial characterization (i.e., next-generation sequencing of the 16S rRNA gene and fluorescence in situ hybridization) showed that BERs operated with a poised cathode at -260 mV (vs. Ag/AgCl) significantly enriched nitrifying microorganisms in the anode and denitrifying microorganisms and planctomycetes in the cathode. Interestingly, the electrochemical enrichment did not increase the total number of microorganisms in the formed biofilms but controlled their composition. Thus, this work shows the first successful attempt to electrochemically enrich marine nitrifying and denitrifying microorganisms and presents a technique to accelerate the start-up process of BERs to remove dissolved inorganic nitrogen and total organic carbon from seawater.

Microbial carbon, sulfur, iron, and nitrogen cycling linked to the potential remediation of a meromictic acidic pit lake.

Cueva de la Mora is a permanently stratified acidic pit lake and a model system for extreme acid mine drainage (AMD) studies. Using a combination of amplicon sequencing, metagenomics and metatranscriptomics we performed a taxonomically resolved analysis of microbial contributions to carbon, sulfur, iron, and nitrogen cycling. We found that active green alga Coccomyxa onubensis dominated the upper layer and chemocline. The chemocline had activity for iron(II) oxidation carried out by populations of Ca. Acidulodesulfobacterium, Ferrovum, Leptospirillium, and Armatimonadetes. Predicted activity for iron(III) reduction was only detected in the deep layer affiliated with Proteobacteria. Activity for dissimilatory nitrogen cycling including nitrogen fixation and nitrate reduction was primarily predicted in the chemocline. Heterotrophic archaeal populations with predicted activity for sulfide oxidation related to uncultured Thermoplasmatales dominated in the deep layer. Abundant sulfate-reducing Desulfomonile and Ca. Acidulodesulfobacterium populations were active in the chemocline. In the deep layer, uncultured populations from the bacterial phyla Actinobacteria, Chloroflexi, and Nitrospirae contributed to both sulfate reduction and sulfide oxidation. Based on this information we evaluated the potential for sulfide mineral precipitation in the deep layer as a tool for remediation. We argue that sulfide precipitation is not limited by microbial genetic potential but rather by the quantity and quality of organic carbon reaching the deep layer as well as by oxygen additions to the groundwater enabling sulfur oxidation. Addition of organic carbon and elemental sulfur should stimulate sulfate reduction and limit reoxidation of sulfide minerals.

Novel Microorganisms Contribute to Biosulfidogenesis in the Deep Layer of an Acidic Pit Lake.

Cueva de la Mora is a permanently stratified acidic pit lake with extremely high concentrations of heavy metals at depth. In order to evaluate the potential for in situ sulfide production, we characterized the microbial community in the deep layer using metagenomics and metatranscriptomics. We retrieved 18 high quality metagenome-assembled genomes (MAGs) representing the most abundant populations. None of the MAGs were closely related to either cultured or non-cultured organisms from the Genome Taxonomy or NCBI databases (none with average nucleotide identity >95%). Despite oxygen concentrations that are consistently below detection in the deep layer, some archaeal and bacterial MAGs mapped transcripts of genes for sulfide oxidation coupled with oxygen reduction. Among these microaerophilic sulfide oxidizers, mixotrophic Thermoplasmatales archaea were the most numerous and represented 24% of the total community. Populations associated with the highest predicted in situ activity for sulfate reduction were affiliated with Actinobacteria, Chloroflexi, and Nitrospirae phyla, and together represented about 9% of the total community. These MAGs, in addition to a less abundant Proteobacteria MAG in the genus Desulfomonile, contained transcripts of genes in the Wood-Ljungdahl pathway. All MAGs had significant genetic potential for organic carbon oxidation. Our results indicate that novel acidophiles are contributing to biosulfidogenesis in the deep layer of Cueva de la Mora, and that in situ sulfide production is limited by organic carbon availability and sulfur oxidation.

Bioprospecting for electrochemically active perchlorate-reducing microorganisms.

This study evaluated the electrochemical capacity of four perchlorate-reducing microorganisms (PRMs) isolated from an Altiplanic Andean watershed naturally pressured with perchlorate. Three-electrode electrochemical cells were used to test the electrochemical activity of the obtained isolates. Electrochemical evaluation (i.e., cyclic voltammetry, electrochemical impedance spectroscopy, chronoamperometry) revealed that two isolates identified as Dechloromonas sp. CS-1 and Clostridioides sp. CS-2 are electrochemically active PRMs. Bacterial isolates exhibiting cathodic peaks at -651 mV and -303 mV (vs. Ag/AgCl) for CS-1 and CS-2, respectively. Electrotrophic perchlorate removal was demonstrated by a 6-days chronoamperometry with removal rates of 27 and 17 mg L-1 day-1 and cathodic efficiencies of 93% and 45%, for CS-1 and CS-2, respectively. Chemical and electrochemical results suggest two different mechanisms of electrotrophic perchlorate removal, a complete eight-electron bio-reduction (i.e., perchlorate to chloride) for CS-1 and a partial two-electron bio-reduction (i.e., perchlorate to chlorate) for CS-2. The observed differences could be linked to their enzymatic differences, as in their membrane compositions. Thus, the results of this work increase the limited number of known electrotrophic microorganisms and expand the application of bioelectrochemical systems to develop new perchlorate treatment and remediation technologies.

Surfactant Protein D Influences Mortality During Abdominal Sepsis by Facilitating Escherichia coli Colonization in the Gut.

Determine the role of surfactant protein D (SPD) in sepsis. DESIGN: Murine in vivo study. SETTING: Research laboratory at an academic medical center. PATIENTS: SPD knockout (SPD-/-) and wild-type (SPD+/+) mice. INTERVENTIONS: SPD-/- and SPD+/+ mice were subjected to cecal ligation and puncture (CLP). After CLP, Escherichia coli bacteremia was assessed in both groups. Cecal contents from both groups were cultured to assess for colonization by E. coli. To control for parental effects on the microbiome, SPD-/- and SPD+/+ mice were bred from heterozygous parents, and levels of E. coli in their ceca were measured. Gut segments were harvested from mice, and SPD protein expression was measured by Western blot. SPD-/- mice were gavaged with green fluorescent protein, expressing E. coli and recombinant SPD (rSPD). MEASUREMENTS AND MAIN RESULTS: SPD-/- mice had decreased mortality and decreased E. coli bacteremia compared with SPD+/+ mice following CLP. At baseline, SPD-/- mice had decreased E. coli in their cecal flora. When SPD-/- and SPD+/+ mice were bred from heterozygous parents and then separated after weaning, less E. coli was cultured from the ceca of SPD-/- mice. E. coli gut colonization was increased by gavage of rSPD in SPD-/- mice. The source of enteric SPD in SPD+/+ mice was the gallbladder. CONCLUSIONS: Enteral SPD exacerbates mortality after CLP by facilitating colonization of the mouse gut with E. coli.