Determinación de la prevalencia de cepas potencialmente patogénicas y conocimiento de la comunidad médica sobre Clostridium difficile en centros de atención en salud de la ciudad de Bogotá

En la primera fase del proyecto, se implementó una novedosa técnica llamada RPA (recombinase polymerase amplification) como un método de diagnóstico para C. difficile, la cual resulta ser una técnica de bajo costo, alta sensibilidad y especificidad similar a la observada a la presentada por el PCR en tiempo real, pero sin necesidad de equipos costosos como termocicladores. En una segunda fase, se plantea determinar el conocimiento de personal de salud sobre la infección causada por C. difficile en centros de atención y cuidado a la salud. Para esto, se realizará un estudio observacional de corte transversal con enfoque cuantitativo, para determinar el conocimiento del personal interviniente con respecto a la práctica, la prevención de la infección por esta bacteria potencialmente patógena en al menos tres institucioneshospitalarias y/o tres hogares geriátricos

Determinación de la prevalencia de cepas potencialmente patogénicas y conocimiento de la comunidad médica sobre Clostridium difficile en centros de atención en salud de la ciudad de Bogotá

En la primera fase del proyecto, se implementó una novedosa técnica llamada RPA (recombinase polymerase amplification) como un método de diagnóstico para C. difficile, la cual resulta ser una técnica de bajo costo, alta sensibilidad y especificidad similar a la observada a la presentada por el PCR en tiempo real, pero sin necesidad de equipos costosos como termocicladores. En una segunda fase, se plantea determinar el conocimiento de personal de salud sobre la infección causada por C. difficile en centros de atención y cuidado a la salud. Para esto, se realizará un estudio observacional de corte transversal con enfoque cuantitativo, para determinar el conocimiento del personal interviniente con respecto a la práctica, la prevención de la infección por esta bacteria potencialmente patógena en al menos tres institucioneshospitalarias y/o tres hogares geriátricos

Next-Generation Probiotics Targeting \u3ci\u3eClostridium difficile\u3c/i\u3e through Precursor- Directed Antimicrobial Biosynthesis

Integration of antibiotic and probiotic therapy has the potential to lessen the public health burden of antimicrobial-associated diseases. Clostridium difficile infection (CDI) represents an important example where the rational design of next-generation probiotics is being actively pursued to prevent disease recurrence. Because intrinsic resistance to clinically relevant antibiotics used to treat CDI (vancomycin, metronidazole, and fidaxomicin) is a desired trait in such probiotic species, we screened several bacteria and identified Lactobacillus reuteri to be a promising candidate for adjunct therapy. Human-derived L. reuteri bacteria convert glycerol to the broad-spectrum antimicrobial compound reuterin. When supplemented with glycerol, strains carrying the pocR gene locus were potent reuterin producers, with L. reuteri 17938 inhibiting C. difficile growth at a level on par with the level of growth inhibition by vancomycin. Targeted pocR mutations and complementation studies identified reuterin to be the precursor-induced antimicrobial agent. Pathophysiological relevance was demonstrated when the codelivery of L. reuteri with glycerol was effective against C. difficile colonization in complex human fecal microbial communities, whereas treatment with either glycerol or L. reuteri alone was ineffective. A global unbiased microbiome and metabolomics analysis independently confirmed that glycerol precursor delivery with L. reuteri elicited changes in the composition and function of the human microbial community that preferentially targets C. difficile outgrowth and toxicity, a finding consistent with glycerol fermentation and reuterin production. Antimicrobial resistance has thus been successfully exploited in the natural design of human microbiome evasion of C. difficile, and this method may provide a prototypic precursor-directed probiotic approach. Antibiotic resistance and substrate bioavailability may therefore represent critical new determinants of probiotic efficacy in clinical trials

Pathologic Inflammation in Malnutrition Is Driven by Proinflammatory Intestinal Microbiota, Large Intestine Barrier Dysfunction, and Translocation of Bacterial Lipopolysaccharide

Acute malnutrition, or wasting, is implicated in over half of all deaths in children under five and increases risk of infectious disease. Studies in humans and preclinical models have demonstrated that malnutrition is linked to an immature intestinal microbiota characterized by increased prevalence of Enterobacteriaceae. Observational studies in children with moderate acute malnutrition (MAM) have also observed heightened systemic inflammation and increased circulating bacterial lipopolysaccharides (LPS; endotoxin). However, the mechanisms that underpin the systemic inflammatory state and endotoxemia, and their pathophysiological consequences, remain uncertain. Understanding these pathophysiological mechanisms is necessary to design targeted treatments that will improve the unacceptable rate of failure or relapse that plague current approaches. Here we use a mouse model of MAM to investigate the mechanisms that promote inflammation in the malnourished host. We found that mice with MAM exhibited increased systemic inflammation at baseline, increased translocation of bacteria and bacterial LPS, and an exaggerated response to inflammatory stimuli. An exaggerated response to bacterial LPS was associated with increased acute weight loss. Remarkably, intestinal inflammation and barrier dysfunction was found in the cecum and colon. The cecum showed a dysbiotic microbiota with expansion of Gammaproteobacteria and some Firmicutes, and contraction of Bacteroidetes. These changes were paralleled by an increase in fecal LPS bioactivity. The inflammatory phenotype and weight loss was modulated by oral administration of non-absorbable antibiotics that altered the proportion of cecal Gammaproteobacteria. We propose that the heightened inflammation of acute malnutrition is the result of changes in the intestinal microbiota, intestinal barrier dysfunction in the cecum and colon, and increased systemic exposure to LPS

Identification of Small Molecule Lead Compounds for Visceral Leishmaniasis Using a Novel Ex Vivo Splenic Explant Model System

Visceral leishmaniasis is a life threatening parasitic disease present in several countries of the world. New drugs are needed to treat this disease because treatments are becoming increasingly ineffective. We established a novel system to screen for new anti-leishmanial compounds that utilizes spleen cells from hamsters infected with the parasite Leishmania donovani. The parasite strain we used was genetically engineered to emit light by the incorporation of the firefly luciferase gen. This laboratory test system has the advantage of reproducing the cellular environment where the drug has to combat the infection. The efficacy of the compounds is easily determined by measuring the light emitted by the surviving parasites in a luminometer after exposing the infected cells to the test compounds. The screening of more than 4,000 molecules showed that 84 (2.1%) of them showed anti-leishmanial activity and had an acceptable toxicity evaluation. Eighty two percent of these molecules, which had varied chemical structures, were previously unknown to have anti-leishmanial activity. Further studies in animals of these new chemical entities may identify drug candidates for the treatment of visceral leishmaniasis

La quimioinformática, una herramienta eficiente para desarrollar los medicamentos del futuro

The chemoinformatics is one of the best examples on how to translate data information in knowledge, in way to lead the process of research and development in the pharmaceutical and related industries. These new technologies allow better use of resources and time invested in the identification, development and optimization of new drugs. The chemoinformatics arises from the combination of scientific and technological tools with the three-dimensional understanding and manipulation of the organic chemistry applied to therapeutic research. As the technologies associated with chemoinformatics become more common in the pharmaceutical laboratories, there�s an increase in the number of publications that report higher efficiency in the drug development, to assess the molecule and target selection, and absorption, distribution, metabolism, and excretion (ADMET) properties of chemical libraries using the virtual screening versus the empirical analysis. This review presents the most relevant concepts in chemoinformatics, specifically in the pharmacophore design, coupling analysis of the therapeutic target, and quantification of the relationship between structure and activity.La quimioinformática es uno de los mejores ejemplos sobre como los datos producen información que a su vez promueve el conocimiento, a través del cual es posible el proceso de investigación y desarrollo en la industria farmacéutica y afines. Estas nuevas tecnologías permiten un mejor uso de recursos y del tiempo invertido en el proceso de identificación, desarrollo y optimización de nuevos medicamentos. La quimioinformática nace de la combinación científica de las herramientas informáticas y tecnológicas con la comprensión tridimensional y transformación de la química orgánica, aplicada a la investigación terapéutica principalmente. Conforme las tecnologías asociadas a la quimioinformática se hacen más comunes en los laboratorios farmacéuticos, así mismo incrementa la cantidad de publicaciones que reportan mayor eficiencia en el proceso de selección y desarrollo de medicamentos al evaluar las propiedades de Absorción, Distribución, Metabolismo, Excreción y Toxicidad (ADMET) de las librerías mediante el análisis virtual (virtual screening) frente al análisis empírico. En esta revisión se presentan los conceptos más relevantes a la investigación quimioinformática, específicamente el diseño basado en el farmacóforo, el análisis del acoplamiento al objetivo terapéutico y la cuantificación de las relaciones entre la estructura y la actividad

Antileishmanial Activity of Disulfiram and Thiuram Disulfide Analogs in an Ex Vivo Model System Is Selectively Enhanced by the Addition of Divalent Metal Ions

Current treatments for cutaneous and visceral leishmaniasis are toxic, expensive, difficult to administer, and limited in efficacy and availability. Disulfiram has primarily been used to treat alcoholism. More recently, it has shown some efficacy as therapy against protozoan pathogens and certain cancers, suggesting a wide range of biological activities. We used an ex vivo system to screen several thiuram disulfide compounds for antileishmanial activity. We found five compounds (compound identifier [CID] 7188, 5455, 95876, 12892, and 3117 [disulfiram]) with anti-Leishmania activity at nanomolar concentrations. We further evaluated these compounds with the addition of divalent metal salts based on studies that indicated these salts could potentiate the action of disulfiram. In addition, clinical studies suggested that zinc has some efficacy in treating cutaneous leishmaniasis. Several divalent metal salts were evaluated at 1 μM, which is lower than the normal levels of copper and zinc in plasma of healthy individuals. The leishmanicidal activity of disulfiram and CID 7188 were enhanced by several divalent metal salts at 1 μM. The in vitro therapeutic index (IVTI) of disulfiram and CID 7188 increased 12- and 2.3-fold, respectively, against L. major when combined with ZnCl2. The combination of disulfiram with ZnSO4 resulted in a 1.8-fold increase in IVTI against L. donovani. This novel combination of thiuram disulfides and divalent metal ions salts could have application as topical and/or oral therapies for treatment of cutaneous and visceral leishmaniasis

Development of an Ex Vivo Lymph Node Explant Model for Identification of Novel Molecules Active against Leishmania major

Leishmaniasis is a vector-borne zoonotic infection affecting people in tropical and subtropical regions of the world. Current treatments for cutaneous leishmaniasis are difficult to administer, toxic, expensive, and limited in effectiveness and availability. Here we describe the development and application of a medium-throughput screening approach to identify new drug candidates for cutaneous leishmaniasis using an ex vivo lymph node explant culture (ELEC) derived from the draining lymph nodes of Leishmania major-infected mice. The ELEC supported intracellular amastigote proliferation and contained lymph node cell populations (and their secreted products) that enabled the testing of compounds within a system that mimicked the immunopathological environment of the infected host, which is known to profoundly influence parasite replication, killing, and drug efficacy. The activity of known antileishmanial drugs in the ELEC system was similar to the activity measured in peritoneal macrophages infected in vitro with L. major. Using the ELEC system, we screened a collection of 334 compounds, some of which we had demonstrated previously to be active against L. donovani, and identified 119 hits, 85% of which were confirmed to be active by determination of the 50% effective concentration (EC50). We found 24 compounds (7%) that had an in vitro therapeutic index (IVTI; 50% cytotoxic/effective concentration [CC50]/EC50) > 100; 19 of the compounds had an EC50 below 1 μM. According to PubChem searchs, 17 of those compounds had not previously been reported to be active against Leishmania. We expect that this novel method will help to accelerate discovery of new drug candidates for treatment of cutaneous leishmaniasis