Interacción del microbioma intestinal y el hueso / Interaction between the intestinal microbiome and bone

El "microbioma" no solo está constituido por los microbios, sino por todos los componen-tes que viven en el mismo hábitat conforman-do un nicho ecológico. Es decir, está conformado por los microorganismos (bacterias, hongos, protozoos, etc.), todo el espectro de moléculas producidas por ellos tales como sus componentes estructurales (ácidos nucleicos, proteínas, lípidos y glúcidos), meta-bolitos, toxinas, etc., y las moléculas producidas por el huésped. El microbioma intestinal (MI) ha emergido como un factor que tiene un gran efecto sobre la cantidad, calidad y fuerza del hueso. Las investigaciones revelan que la homeostasis ósea está ligada al micro-bioma saludable, mientras que la disbiosis (alteración en la biodiversidad microbiana) puede exacerbar la actividad osteoclástica y promover la osteoporosis. Los mecanismos potenciales involucrados en la interacción del microbioma intestinal y el hueso son la influencia del metabolismo del huésped, el mantenimiento de la integridad intestinal y regulación de la absorción de nutrientes, la regulación del eje intestino-sistema inmune y la modulación del sistema endocrino. Es decir que hay múltiples vías por las cuales el MI influye sobre el hueso, pero estos y otros mecanismos deben profundizarse más aún. También es necesario que se identifiquen y caractericen mejor los microorganismos que están asociados a las enfermedades óseas. El conocimiento de estos aspectos podría ser útil para el desarrollo de herramientas terapéuticas basadas en el MI que puedan mejorar la eficacia de los distintos tratamientos existentes. (AU)

The microbiome is not only constituted by microbes, but by all the components that live in the same habitat forming an ecological niche. It is conformed by the microorganisms ( bacteria, fungi, protozoa, etc), the entire spectrum of molecules produced by them (nucleic acids, proteins, lipid and carbohydrates, metabolites, toxins, etc) and the molecules produced by the host. The intestinal microbiome (IM) has emerged as a factor with great effects on the quantity, quality and strength of bone. The investigations reveal that bone homeostasis is linked to the healthy microbiome, while the dysbiosis (alteration in the microbial biodiversity) can exacerbate the osteoclastic activity and promote osteoporosis. The potential mechanisms involved in the interaction between IM and bone are the influence of the host metabolism, the maintenance of the intestinal integrity and regulation of the nutrient absorption, the regulation of the intestine/ immune system axis and the modulation of the endocrine system. That is, there are multiple ways through which IM influences on bone, but these and other mechanisms need to be further studied. It is also necessary to identify and characterize the microorganisms associated with the bone diseases. Knowledge of these aspects could be useful to develop therapeutical tools based on the IM that could improve the efficacy of the current treatments. (AU)

Association between productive parameters and intestinal histomorphological findings in broilers supplemented with probiotics (Saccharomyces cerevisiae, Lactobacillus acidophilus and Bacillus subtilis) / Asociación entre parámetros productivos y hallazgos histomorfológicos en pollos de engorde suplementados con probióticos (Saccharomyces cerevisiae, Lactobacillus acidophilus y Bacillus subtilis)

SUMMARY: This study evaluates the effect of probiotics Saccharomyces cerevisiae, Lactobacillus acidophilus and Bacillus subtilis on production parameters and intestinal histomorphology of broilers of 45 days of age. Eleven 45-day-old Ross 500 broilers were used and classified as control group (CG) (n = 5) or supplemented with probiotics group (n = 8). Histopathological evaluation of duodenum, ileum, and jejunum was performed. The area of the villi height, base and apex were evaluated as well as the size and number of crypts. In addition, mucus production was quantified in different portions of the small intestine. The villi present duodenum of broilers supplemented with probiotics had a greater area (p = 0.0127), a greater basal width (p = 0.0049) and a greater apical width (p = 0.0024), as well as a greater crypt area (p = 0.0189). Significantly higher levels of mucus were noted in the duodenum (p = 0.0480) and jejunum (p = 0.0480) of broilers supplemented with probiotics. We suggest that probiotic supplementation improve the intestinal nutrients absorption.

RESUMEN: Este estudio evalúa el efecto del uso de probióticos como: Saccharomyces cerevisiae, Lactobacillus acidophilus, Bacillus subtilis en parámetros productivos e histomorfologia intestinal de pollos de engorde de 45 días de edad. Fueron usados 11, los cuales fueron clasificados en grupo control (CG) (n = 5) y grupo suplementado con probióticos (PG) (n = 8). Fue realizado análisis histopatológico de secciones de duodeno, íleon y yeyuno. Fue evaluado ancho, altura y área del ápice de la vellosidad, área y número de criptas. Además, fue estimada la producción de moco en los diferentes segmentos del intestino delgado. Fue observada mayor área de la vellosidad en duodeno, PG (p = 0.0127), ancho basal mayor en PG (p = 0.0049) ancho apical mayor en PG (p = 0.0024), así como mayor área de criptas en PG (p = 0.0189). No fueron encontradas diferencias significativas respecto a los segmentos de yeyuno e íleon. PG presentó mayor producción de moco en duodeno (p = 0.0480) y en yeyuno (p = 0.0480). Concluimos que la suplementación con probióticos en pollos de engorde genera cambios en la histomorfologia intestinal, evidenciables en áreas apicales y basales de las vellosidades intestinales. Soporte financiero: Dirección General de Investigaciones - Universidad de los Llanos.

Saccharomyces cerevisiae as a probiotic agent and a possible aflatoxin B1 adsorbent in simulated fish intestinal tract conditions / Saccharomyces cerevisiae como agente probiótico e possível adsorvente de aflatoxina B1 em condições simuladas do trato intestinal de peixes

The aim of this study was to evaluate in vitro the probiotic potential and absorption of Saccharomyces cerevisiae for the aflatoxin B1 in simulated fish intestinal tract conditions. Three yeast strains were used, two from brewery: S. cerevisiae RC1 and S. cerevisiae RC3 and one from a fish farming environment: S. cerevisiae A8L2. The selected yeasts were subjected to the following in vitro tests: homologous inhibition, self-aggregation, co-aggregation, antibacterial activity, gastrointestinal conditions tolerance and adsorption of AFB1. All S. cerevisiae strains showed good capability of self-aggregation and co-aggregation with pathogenic bacteria. All yeast strains were able to survive the gastrointestinal conditions. In acidic conditions, the factors (strain vs. time) had interaction (P=0.0317), resulting in significant variation among the strains tested in the time periods analyzed. It was observed that there was also interaction (P=0.0062) in intestinal conditions, with an increased number of cells in the 12-hour period for all strains tested. In the adsorption test, the A8L2 strain was statistically more effective (P<0.005) for both AFB1 concentrations evaluated in this study (10 and 25ng/mL). Thus, it was observed that the strains of S. cerevisiae have potential probiotic and adsorbent of AFB1.(AU)

Objetivou-se, com esta pesquisa, avaliar in vitro o potencial probiótico e adsorvente de Saccharomyces cerevisiae para aflatoxina B1 em condições simuladas do trato intestinal de peixes. Foram utilizadas três cepas de leveduras, sendo duas provenientes de cervejaria: S. cerevisiae RC1 e S. cerevisiae RC3, e uma de ambiente de piscicultura: S. cerevisiae A8L2. As leveduras selecionadas foram submetidas aos seguintes testes in vitro: inibição homóloga, autoagregação, coagregação, atividade antibacteriana, viabilidade às condições gastrointestinais e adsorção de AFB1. Todas as estirpes de S. cerevisiae mostraram boa capacidade de autoagregação e coagregação com bactérias patogênicas. Todas as estirpes de levedura foram capazes de sobreviver às condições gastrointestinais. Em condições ácidas, os fatores (cepa x tempo) tiveram interação (P=0,0317), resultando em variações significativas entre as cepas testadas nos períodos de tempo analisados. Observou-se que também houve interação (P=0,0062) em condições intestinais, havendo um aumento do número de células no período de 12h para todas as cepas avaliadas. No ensaio de adsorção, a estirpe A8L2 foi a mais eficaz estatisticamente (P<0,005), para as duas concentrações de AFB1 avaliadas neste estudo (10 e 25ng. mL-1). Dessa forma, conclui-se que as cepas de Saccharomyces cerevisiae possuem potencial probiótico e adsorvente de AFB1.(AU)

Expressão e atividade de sistemas de dois componentes (TCS) de Salmonella enterica sorovar Typhimurium no contexto do metaboloma intestinal humano / Expression and activity of two-component systems of Salmonella enterica sorovar Typhimurium in the context of the human intestinal metabolome

A interação entre membros do microbioma intestinal humano, células hospedeiras e patógenos invasores pode ocorrer de diversas formas, sendo uma delas através de pequenas moléculas chamadas metabólitos. A percepção e resposta efetiva de um microrganismo às diferentes condições encontradas em seu ambiente, incluindo metabólitos produzidos por outros microrganismos, são fatores importantes para sua adaptação, sobrevivência e disseminação. Os sistemas de dois componentes (TCS) permitem a percepção e resposta a mudanças ambientais, regulando a expressão de genes específicos. Nosso grupo mostrou anteriormente que um extrato orgânico de fezes humanas (EF), bem como o ácido 3,4-dimetilbenzoico (3,4-DMB), encontrado no EF, inibe a capacidade de Salmonella enterica sorovar Typhimurium de invadir células hospedeiras. O presente trabalho propôs investigar o impacto do microbioma intestinal humano, bem como de pequenas moléculas produzidas por Clostridium citroniae (membro deste microbioma) na expressão e atividade dos genes de TCS de Salmonella. Os metabólitos de EF e de culturas puras de C. citroniae foram extraídos com acetato de etila e adicionados a meio de cultura. O pH do meio foi ajustado (~ 7,4) e a solução foi esterilizada por filtragem. Salmonella foi cultivada na presença ou ausência do EF e do extrato de C. citroniae, bem como do ácido 3,4-DMB, em condições aeróbias e anaeróbias, até alcançar o meio da fase logarítmica de crescimento. O RNA foi extraído para a realização de PCR em Tempo Real utilizando iniciadores direcionados a quase todos os TCS de Salmonella. Nossos resultados mostraram que vários genes de TCS envolvidos na virulência de Salmonella (SsrAB, EnvZ-OmpR, QseCB, PhoQP, TorSR, TtrRS) foram regulados diferencialmente por esses metabólitos, tanto em condições aeróbias quanto anaeróbias. EnvZ-OmpR, PhoPQ e SsrAB estão diretamente envolvidos na regulação das Ilhas de Patogenicidade 1 e 2 de Salmonella. QseCB é crucial para a detecção de quorum em Salmonella, de hormônios hospedeiros e para a regulação da motilidade (swimming). Vários outros TCS também foram regulados, incluindo TorSR e TtrRS, envolvidos na regulação da respiração anaeróbica de N-óxido de trimetilamina (TMAO) e tetrationato, respectivamente. Esses compostos são importantes para a sobrevivência de Salmonella no ambiente anaeróbico do intestino humano. Nossos resultados de avaliação de expressão gênica global de Salmonella cultivada na presença de ácido 3,4-DMB (aerobiose e anaerobiose) bem como na presença do EF em anaerobiose, mostraram que genes condificados em SPI-1 e SPI-2, SPI-4 e alguns genes do TCS foram reprimidos, enquanto genes marR, marB e marA foram ativadas nessas condições. Adicionalmente, comparamos nossos resultados de RNAseq, de Salmonella cultivada na presença do ácido 3,4-DMB em aerobiose, com resultados disponíveis da base de dados Salmonella Compendium. Ainda, a capacidade de Salmonella de adentrar e sobreviver dentro de células fagocíticas (macrófagos RAW 264.7) parece ser afetada pelas três condições testadas neste trabalho. Nossos resultados mostram que importantes vias de sinalização da virulência de Salmonella podem ser moduladas pelos metabólitos presentes no microbioma intestinal humano e abrem caminhos para novas pesquisas sobre a sinalização intercelular microbioma-patógeno no ambiente intestinal.

The interaction between members of the human gut microbiome, host cells and invading pathogens often occurs through small molecules, also called metabolites. The perception and effective response of a microorganism to the different conditions found in its environment, including metabolites produced by other microbes, is important for its adaptation, survival and dissemination. Two-component systems (TCS) allow the perception and response to environmental changes by regulating the expression of specific genes. Our group previously showed that organic extracts of human feces (EF) as well as the specific metabolite 3,4-dimethylbenzoic acid (3,4-DMB) found within the EF, inhibit the ability of Salmonella enterica sorovar Typhimurium to invade host cells. In the present work, we investigated the impact of the human gut microbiome as well as small molecules produced by Clostridium citroniae (a member of this microbiome) on the expression and activity of Salmonella TCS genes. Metabolites (from feces or C. citroniae cultures) were extracted using ethyl acetate and added to culture medium. The pH of the medium was adjusted (~7.4), and the solution was filter sterilized. Salmonella was grown in the presence or absence of the organic extracts as well as 3,4-DMB acid under aerobic and anaerobic conditions until it reached mid-log growth. RNA was then extracted for Real-time PCR using primers targeting almost all Salmonella TCS. Our results showed that several TCS involved in Salmonella virulence (SsrAB, EnvZ-OmpR, QseCB, PhoQP, TorSR, TtrRS) were differentially regulated by these metabolites both in aerobic and anaerobic conditions. EnvZ-OmpR, PhoPQ, and SsrAB are directly involved in the regulation of Salmonella Pathogenicity Islands 1 and 2. QseCB is crucial for Salmonella =quorum sensing, sensing of host hormones and regulation of swimming motility. Several other TCS were also regulated, including TorSR and TtrRS, which are involved in the anaerobic respiration of trimethylamine N-oxide (TMAO) and tetrathionate, respectively. These compounds are important for Salmonella survival in the anaerobic environment of the human gut. Our results of the evaluation of global Salmonella gene expression grown in the presence of 3,4-DMB acid (aerobiosis and anaerobiosis) as well as in the presence of EF in anaerobiosis, showed that genes encoded in SPI-1 and SPI-2, SPI-4 and some TCS genes have been repressed, while multiple drug resistance genes, as well marR, marB and marA genes have been activated under these conditions. Besides, we compared our results of RNAseq, Salmonella was grown in the presence of 3,4-DMB acid in aerobiosis, with results available from the Salmonella Compendium database. Also, Salmonella's ability to enter and survive within phagocytic cells (macrophages RAW 264.7) appears to be affected by the three conditions tested in this work. Our results show that important Salmonella virulence signalling pathways can be modulated by the metabolites present in the human intestinal microbiome and open the way for further research on the microbiome-pathogen intercellular signalling in the intestinal environment.

Morfología y repercusiones diagnóstico-terapéuticas de las lesiones preneoplásicas gástricas / Morphology and diagnostic determinants of gastric precancerous conditions

El carcinoma gástrico (CG) de tipo intestinal se origina en un epitelio displásico, que a su vez se desarrolla en medio de una atrofia gástrica (AG) y metaplasia intestinal (MI). La infección por Helicobacter pylori (HP) es la causa más frecuente de AG, causando una pangastritis atrófica multifocal. Entre otras condiciones que producen inflamación crónica de la mucosa gástrica se encuentran también la gastritis autoinmune y la anemia perniciosa. El marco conceptual sobre el cual descansa gran parte de la investigación actual y nuestra comprensión de los cambios que ocurren en la mucosa gástrica se debe a la denominada "cascada de Correa"; quien planteó que la mucosa gástrica crónicamente inflamada, da paso a la AG, que va adquiriendo focos de MI y en dicho epitelio se desarrollará finalmente una displasia (DIS). Se ha acuñado el término lesiones preneoplásicas gástricas (LPG), para referirse a: AG, MI y DIS.Después de la erradicación de HP, se ha demostrado una reducción general de la incidencia de CG; efecto que no es tan claro, cuando la pangastritis por HP ha evolucionado a AG extensa. De tal modo que el efecto de la erradicación de HP medido a través de EC, ha sido poco consistente. La AG grave diagnosticada por histología representa la condición de mayor riesgo. Por otra parte, la MI puede ser de tipo intestinal (delgado-entérica ó incompleta) y la colónica (colónica ó completa) considerándose a esta última, como la variedad de peor pronóstico. El diagnóstico histológico de este tipo de lesiones determina que quien las padece, debe someterse a vigilancia endoscópica. El objetivo de este manuscrito fue resumir la evidencia existente respecto de las LPG, en términos de su caracterización morfológica y sus repercusiones diagnóstico-terapéuticas (significado patológico, graduación del riesgo, vigilancia recomendada; y factores de riesgo).

Gastric carcinoma (GC) of intestinal type, originates from a dysplastic epithelium, which in turn develops in the midst of gastric atrophy (GA) and intestinal metaplasia (IM). Helicobacter pylori (HP) infection is the most frequent cause of GA, causing a multifocal atrophic pangastritis. Among other conditions that produce chronic inflammation of gastric mucosa are also autoimmune gastritis and pernicious anemia. The conceptual framework on which much of current research rests and our understanding of the changes that occur in the gastric mucosa is due to the so-called "Correa waterfall"; who stated that gastric mucosa chronically inflamed, gives way to the GA, which is acquiring foci of IM and in said epithelium a dysplasia (DIS) will eventually develop. The term precancerous conditions (PCC) of the gastric mucosa have been coined to refer to: GA, IM and DIS. After HP eradication, a general reduction in the incidence of GC has been demonstrated; effect that is not so clear, when pangastritis by HP has evolved to extensive GA. Thus, the effect of HP eradication measured through clinical trials has been inconsistent. Severe GA diagnosed represents the highest risk condition. On the other hand, IM can be enteric (grade I), enterocolic (grade II) or colonic (grade III); considering IM III as the variety with the worst prognosis. Histological diagnosis of gastric PCC, determines that the one who suffers them, must undergo endoscopic surveillance. The aim of this manuscript was to update morphological aspects and diagnostic-therapeutic scope of gastric PCC.

Β-Glucan of candida albicans cell wall extract inhibits salmonella typhimurium colonization by potentiating cellular immunity (cd8 + and cd4 + t cells)

Abstract INTRODUCTION: Antimicrobial resistance has been reported in the drugs used for the treatment of typhoid fever. The immunomodulatory substance β-glucan can be used as an alternative therapy as it potentiates host immunity. The aims of this study are to observe the effect of Candida albicans cell wall (CCW) extract towards host immunity (TCD8+ and TCD4+ cells in spleen, intestinal sIgA) and its capacity to kill Salmonella in the intestine and liver of typhoid fever mice models. METHODS: Typhoid fever mice models were created by infecting mice with S. Typhimurium orally. Mice were divided into four groups: the Non-Infected, Infected, CCW (infected mice treated with 300 µg CCW extract/mouse once a day), and Ciprofloxacin groups (infected mice treated with 15 mg/kg BW ciprofloxacin twice a day). RESULTS: Secretory IgA (sIgA) concentrations of mice in the CCW group remained unchanged. However, their TCD4+ and TCD8+ cells increased substantially compared to those in the Non-Infected group. In the Ciprofloxacin group, sIgA concentrations increased markedly compared to those in the Non-Infected and CCW groups; TCD4+ and TCD8+ cells also increased significantly compared to those in the Infected Group, but not significant compared to those in the CCW group. Colonization of S. Typhimurium in the intestine and liver decreased significantly in the CCW and Ciprofloxacin groups compared to that in the Infected group, with the lowest reduction being found in the Ciprofloxacin group. CONCLUSIONS The inhibition of S. Typhimurium colonization by CCW is associated with the increase in TCD4+ and TCD8+ cells.

Purification, characterization, mode of action, and enhanced production of Salivaricin mmaye1, a novel bacteriocin from Lactobacillus salivarius SPW1 of human gut origin

Background: Emergence of antibiotic resistance among pathogenic and food spoilage bacteria such as Staphylococcus aureus, Micrococcus luteus, Streptococcus pyogenes, Streptococcus sanguinis, Streptococcus mutans, Bacillus cereus, and Listeria monocytogenes triggered the search for alternative antimicrobials. An investigation aimed at purifying, characterizing, elucidating the mode of action, and enhancing the production of salivaricin from Lactobacillus salivarius of human gut origin was conducted. Results: Salivaricin mmaye1 is a novel bacteriocin purified from L. salivarius isolated from human feces. It is potent at micromolar concentrations and has a molecular weight of 1221.074 Da as determined by MALDI-TOF mass spectrometry. It has a broad spectrum of antibacterial activity. Salivaricin mmaye1 showed high thermal and chemical stability and moderate pH stability. The proteinaceous nature of salivaricin mmaye1 was revealed by the complete loss of activity after treatment with pepsin, trypsin, α-chymotrypsin, protease, and proteinase. Salivaricin mmaye1 is cell wall associated, and adsorption­desorption of the bacteriocin from the cell wall of the producer by pH modification proved successful. It exhibited a bactericidal mode of action mediated by pore formation. Its biosynthesis is regulated by a quorum sensing mechanism. Enhanced production of salivaricin mmaye1 was achieved in a newly developed growth medium. Conclusions: A novel, cell wall adhering, highly potent bacteriocin with a broad spectrum of inhibitory activity, membrane-permeabilizing ability, and enhanced production in a newly constituted medium has been isolated. It has a quorum sensing regulatory system and possesses interesting physicochemical characteristics favoring its future use in food biopreservation. These findings pave the way for future evaluation of its medical and food applications.

Breastfeeding increases microbial community resilience / Aleitamento materno aumenta a resiliência da comunidade microbiana

Abstract Objective Since the present group had already described the composition of the intestinal microbiota of Brazilian infants under low social economic level, the aim of the present study was to analyze the microbial community structure changes in this group of infants during their early life due to external factors. Methods Fecal samples were collected from 11 infants monthly during the first year of life. The infants were followed regarding clinical and diet information and characterized according to breastfeeding practices. DNA was extracted from fecal samples of each child and subjected to Polymerase Chain Reaction - Denaturing Gradient Gel Electrophoresis. Results The results revealed a pattern of similarity between the time points for those who were on exclusive breastfeeding or predominant breastfeeding. Although there were changes in intensity and fluctuation of some bands, the Denaturing Gradient Gel Electrophoresis patterns in the one-year microbial analysis were stable for breastfeeding children. There was uninterrupted ecological succession despite the influence of external factors, such as complementary feeding and antibiotic administration, suggesting microbiota resilience. This was not observed for those children who had mixed feeding and introduction of solid food before the 5th month of life. Conclusion These results suggested an intestinal microbiota pattern resilient to external forces, due to the probiotic and prebiotic effects of exclusive breastfeeding, reinforcing the importance of exclusive breastfeeding until the 6th month of life.

Resumo Objetivo Como nosso grupo já havia descrito a composição da microbiota intestinal de neonatos brasileiros em baixo nível socioeconômico, o objetivo deste estudo foi analisar alterações estruturais da comunidade microbiana desse grupo de neonatos no início de sua vida devido a fatores externos. Métodos Amostras fecais foram coletadas mensalmente de 11 neonatos durante o primeiro ano de vida. Os neonatos foram acompanhados com relação a informações clínicas e nutricionais e caracterizados de acordo com práticas de amamentação. O DNA foi extraído das amostras fecais de cada criança e submetido a análise através da técnica de Reação em Cadeia da Polimerase - Eletroforese em Gel de Gradiente Desnaturante. Resultados Os resultados revelaram um padrão de similaridade entre seus próprios pontos temporais em indivíduos em aleitamento materno exclusivo ou predominante. Apesar de variações na intensidade e flutuação de algumas bandas, o padrão Eletroforese em Gel de Gradiente Desnaturante na análise microbiana de um ano foi estável em crianças em aleitamento materno. Houve sucessão ecológica ininterrupta apesar da influência de fatores externos, como alimentação complementar e administração de antibióticos, sugeriu resiliência da microbiota. Isso não foi observado nas crianças com alimentação heterogênea e introdução de alimentos sólidos antes do quinto mês de vida. Conclusão Nossos resultados sugerem um padrão de microbiota intestinal resiliente a forças externas, devido a efeitos probióticos e prebióticos do aleitamento materno exclusivo, reforçam a importância do aleitamento materno exclusivo até o sexto mês de vida.

Succession Law of Intestinal Flora after Death in SD Rats / 法医学杂志

OBJECTIVES@#To initially explore the sequential changes in the intestinal flora of corpse for the estimation of postmortem interval （PMI）.@*METHODS@#Rats were sacrificed by cervical dislocation, and samples were taken from their intestines using cotton swab to extract the DNA of intestinal flora. The 16S rRNA V3 universal primers were selected for PCR, and the PCR products were used for denatured gradient gel electrophoresis. The diversity and similarity analysis of intestinal flora were analyzed between groups, and the bands were cut from denaturing gradient gel electrophoresis. After purification, PCR and sequencing, the percentage of major bacteria in each group was obtained.@*RESULTS@#The flora diversity showed a reduced tendency from 1st to 30th day after death （ P<0.05）, while the intra-group similarity showed a downward trend （ P<0.05）. The number of bands and intra-group similarity coefficient （Cs） on the first day was higher than that of other groups （ P<0.05）. The intra-group Cs of the 25th and 30th day had a significant difference compared with the 5th day （ P<0.05）. At the genus level, the intestinal flora was mainly composed of Enterococcus sp. on the 1th and 5th day after death, Bacillus thuringienssis was the dominant species on the 10th, 15th and 20th day, and Enterococcus faecalis became the dominant species on the 25th and 30th day.@*CONCLUSIONS@#The composition and structure of intestinal flora change significantly in rats with the time after death, which indicates that the succession of intestinal flora is related to the postmortem interval.

Disruption of the Gut Ecosystem by Antibiotics

The intestinal microbiota is a complex ecosystem consisting of various microorganisms that expands human genetic repertoire and therefore affects human health and disease. The metabolic processes and signal transduction pathways of the host and intestinal microorganisms are intimately linked, and abnormal progression of each process leads to changes in the intestinal environment. Alterations in microbial communities lead to changes in functional structures based on the metabolites produced in the gut, and these environmental changes result in various bacterial infections and chronic enteric inflammatory diseases. Here, we illustrate how antibiotics are associated with an increased risk of antibiotic-associated diseases by driving intestinal environment changes that favor the proliferation and virulence of pathogens. Understanding the pathogenesis caused by antibiotics would be a crucial key to the treatment of antibiotic-associated diseases by mitigating changes in the intestinal environment and restoring it to its original state.

Contribution of flagella and motility to gut colonisation and pathogenicity of Salmonella Enteritidis in the chicken

ABSTRACT Salmonella Enteritidis causes fowl paratyphoid in poultry and is frequently associated to outbreaks of food-borne diseases in humans. The role of flagella and flagella-mediated motility into host-pathogen interplay is not fully understood and requires further investigation. In this study, one-day-old chickens were challenged orally with a wild-type strain Salmonella Enteritidis, a non-motile but fully flagellated (SE ΔmotB) or non-flagellated (SE ΔfliC) strain to evaluate their ability to colonise the intestine and spread systemically and also of eliciting gross and histopathological changes. SE ΔmotB and SE ΔfliC were recovered in significantly lower numbers from caecal contents in comparison with Salmonella Enteritidis at early stages of infection (3 and 5 dpi). The SE ΔmotB strain, which synthesises paralysed flagella, showed poorer intestinal colonisation ability than the non-flagellated SE ΔfliC. Histopathological analyses demonstrated that the flagellated strains induced more intense lymphoid reactivity in liver, ileum and caeca. Thus, in the present study the flagellar structure and motility seemed to play a role in the early stages of the intestinal colonisation by Salmonella Enteritidis in the chicken.

Obesity and gut microbiota - what do we know so far? / Obesidade e microbiota intestinal - o que sabemos até agora?

In the history of medicine, only recently has obesity been recognized as a disease. We know now that it is a pandemic condition, partly explained by the so-called Western lifestyle and related to multiple other comorbidities in various systems. This lyfestyle includes eating large portions, rich in saturated fats and refined sugar, all coupled with sedentary habits. In recent years, the gut microbiota has been indited as a new culprit in pathophysiological aspects involved in obesity. From studies with animals free of bacteria in the digestive tract, known as "germ-free animals", the relevance of intestinal microbiota in the regulation of body fat became evident and its importance has also been extended to the pathophysiology of diseases such as diabetes mellitus and coronary heart disease. Characterization of Toll-like receptors led to the discovery of mechanisms that link the immune system with some metabolic pathways and opened new avenues of a previously unknown world to biological sciences. Increased knowledge about interactions between gut microbiota and the host can certainly reveal, in a not too distant future, new therapeutic perspectives for obesity and its related diseases.

Na história da medicina apenas recentemente a obesidade foi reconhecida como uma doença. Sabemos agora que é uma doença pandêmica, explicada em parte pelo chamado estilo de vida ocidental e relacionado a múltiplas outras comorbidades em vários sistemas. O referido estilo de vida inclui comer grandes porções, ricas em gorduras saturadas e açúcares refinados, e hábitos sedentários. Nos últimos anos, a microbiota intestinal foi associada aos aspectos fisiopatológicos envolvidos na obesidade. De estudos com animais livres de bactérias no trato digestivo, conhecidos como "animais sem germes", a relevância da microbiota intestinal na regulação da gordura corporal tornou-se evidente e sua importância também se estendeu à fisiopatologia de doenças como diabetes mellitus e doença cardíaca coronária. A caracterização dos receptores "Toll-like" levou à descoberta de mecanismos que ligam o sistema imunológico a algumas vias metabólicas e abriram novas avenidas de um mundo anteriormente desconhecido para as ciências biológicas. O aumento do conhecimento sobre as interações entre a microbiota intestinal e o hospedeiro certamente pode revelar, em um futuro não muito distante, novas perspectivas terapêuticas para a obesidade e suas doenças relacionadas.

Multicausal etiology of the enteric syndrome in rabbits from Mexico / Multicausalidad del síndrome entérico en conejos de México

Enteropathies in rabbits are difficult to diagnose; their etiology involves pathogens that act synergistically, causing damage to the intestine. The aim of the present study was isolate enteric pathogens from rabbits in Mexico. Using parasitological, bacteriological and molecular analyses, we screened 58 samples of the intestinal content of rabbits having a clinical history of enteric disease from the southeastern part of the State of Mexico. Out of the 58 samples analyzed, a total of 86 identifications were made, Eimeria spp. were found in 77.5%, followed by Aeromonas spp. in 15.5% and Escherichia coli in 8.6%, which were identified as enteropathogenic E. coli (EPEC), and the presence of the following agents was also confirmed: Salmonella spp., Klebsiella spp., Streptococcus spp., Staphylococcus aureus, Enterococcus spp., Mannheimia spp. and Rotavirus. The concurrent presence of Eimeria spp. with Aeromonas was frequent (15.5%); there was statistical significance for the presence of an association between the clinical profiles and Eimeria spp. (p = 0.000), Mannheimia spp. (p = 0.001), Salmonella spp., Klebsiella spp., Streptococcus spp. and Enterococcus spp. (p = 0.006).

Las enteropatías en conejos son difíciles de diagnosticar, debido a que en su etiología participan patógenos que actúan en sinergia y causan daño al intestino. El objetivo de este estudio fue el aislamiento de patógenos de cuadros entéricos en conejos de México. Mediante métodos parasitológicos, bacteriológicos y moleculares, se analizaron 58 muestras de contenido intestinal de conejos con el antecedente de cuadro clínico entérico procedentes de granjas cunícolas de la zona suroriente del Estado de México. A partir de las 58 muestras se realizaron un total de 86 identificaciones, los patógenos más frecuentes fueron Eimeria spp. (77,6%), seguidas de Aeromonas spp. (15,5%) y de Escherichia coli (8,6%), identificadas como E. coli enterpatogénicas (EPEC). También se determinó la presencia de otros agentes: Salmonella spp., Klebsiella spp., Streptococcus spp., Staphylococcus aureus, Enterococcus spp., Mannheimia spp. y Rotavirus. La presencia concurrente de Eimeria spp. y Aeromonas spp. (15,5%) fue la observación más frecuente. Se encontró asociación estadísticamente significativa entre la presentación del cuadro clínico en conejos y la presencia de Eimeria spp. (p = 0,000), Mannheimia spp. (p = 0,001), Salmonella spp., Klebsiella spp., Streptococcus spp. y Enterococcus spp. (p = 0,006).

Anaerobic bacteria in the intestinal microbiota of Brazilian children

OBJECTIVE: Changes in the neonatal gut environment allow for the colonization of the mucin layer and lumen by anaerobic bacteria. The aim of the present study was to evaluate Bifidobacterium, Lactobacillus and Lactococcus colonization through the first year of life in a group of 12 Brazilian infants and to correlate these data with the levels of Escherichia coli. The presence of anaerobic members of the adult intestinal microbiota, including Eubacterium limosum and Faecalibacterium prausnitzii, was also evaluated. METHODS: Fecal samples were collected during the first year of life, and 16S rRNA from anaerobic and facultative bacteria was detected by real-time PCR. RESULTS: Bifidobacterium was present at the highest levels at all of the studied time points, followed by E. coli and Lactobacillus. E. limosum was rarely detected, and F. prausnitzii was detected only in the samples from the latest time points. CONCLUSION: These results are consistent with reports throughout the world on the community structure of the intestinal microbiota in infants fed a milk diet. Our findings also provide evidence for the influence of the environment on intestinal colonization due to the high abundance of E. coli. The presence of important anaerobic genera was observed in Brazilian infants living at a low socioeconomic level, a result that has already been well established for infants living in developed countries.

Improving reproducibility and external validity. The role of standardization and data reporting of laboratory rat husbandry and housing

Abstract Purpose: To identify the most relevant flaws in standardization in husbandry practices and lack of transparency to report them. This review proposes some measures in order to improve transparency, reproducibility and eventually external validity in experimental surgery experiments with rat model. Methods: We performed a search of scientific articles in PUBMED data base. The survey was conducted from august 2016 to January 2017. The keywords used were "reproducibility", "external validity", "rat model", "rat husbandry", "rat housing", and the time frame was up to January 2017. Articles discarded were the ones which the abstract or the key words did not imply that the authors would discuss any relationship of husbandry and housing with the reproducibility and transparency of reporting animal experiment. Reviews and papers that discussed specifically reproducibility and data reporting transparency were laboriously explored, including references for other articles that could fulfil the inclusion criteria. A total of 246 articles were initially found but only 44 were selected. Results: Lack of transparency is the rule and not the exception when reporting results with rat model. This results in poor reproducibility and low external validity with the consequence of considerable loss of time and financial resources. There are still much to be done to improve compliance and adherence of researchers, editors and reviewers to adopt guidelines to mitigate some of the challenges that can impair reproducibility and external validity. Conclusions: Authors and reviewers should avoid pitfalls of absent, insufficient or inaccurate description of relevant information the rat model used. This information should be correctly published or reported on another source easily available for readers. Environmental conditions are well known by laboratory animal personnel and are well controlled in housing facilities, but usually neglected in experimental laboratories when the rat model is a novelty for the researcher.

Microbiota e barreira intestinal: implicações para obesidade / Microbiota and intestinal barrier: implications for obesity

A epidemia da obesidade é considerada um importante problema de saúde pública na sociedade ocidental, pois ela se relaciona a comorbidades como síndrome metabólica, diabetes mellitus e hipertensão. A microbiota intestinal pode contribuir para o desenvolvimento da obesidade através do aumento da extração energética dos componentes da dieta, da lipogênese, da permeabilidade intestinal e da endotoxemia, mediada especialmente pelos lipopolissacarídeos. Estudos têm demonstrado diferenças na composição da microbiota intestinal entre indivíduos obesos e magros. Ao que parece, o aumento na proporção de Firmicutes em relação a Bacteroidetes parece estar presente na obesidade, podendo ser alterado à medida que ocorre perda de peso. Assim, o objetivo deste estudo foi revisar a literatura acerca dos mecanismos que relacionam a microbiota e a barreira intestinal ao desenvolvimento ou agravamento da obesidade (AU)

The epidemic of obesity is considered an important public health problem in the Western society and is related to comorbidities such as metabolic syndrome, diabetes mellitus, and hypertension. The intestinal microbiota may contribute to the development of obesity by increasing energy extraction from the dietary components, lipogenesis, intestinal permeability, and endotoxemia, especially mediated by lipopolysaccharides. Studies have demonstrated differences in composition of the intestinal microbiota between obese and lean individuals. Apparently, the increase in the proportion of Firmicutes in relation to Bacteroidetes seems to be present in obesity and can be changed during weight loss. The aim of this study was to review the mechanisms that relate microbiota and intestinal barrier to the development or worsening of obesity (AU)

Invasin gimB found in a bovine intestinal Escherichia coli with an adherent and invasive profile

The invasin gimB (genetic island associated with human newborn meningitis) is usually found in ExPEC (Extraintestinal Pathogenic Escherichia coli) such as UPEC (uropathogenic E. coli), NMEC (neonatal meningitis E. coli) and APEC (avian pathogenic E. coli). In NMEC, gimB is associated with the invasion process of the host cells. Due to the importance of E. coli as a zoonotic agent and the scarce information about the frequency of gimB-carrying strains in different animal species, the aim of this study was to investigate the presence of gimB in isolates from bovine, swine, canine and feline clinical samples. PCR was conducted on 196 isolates and the identity of the amplicons was confirmed by sequencing. Of the samples tested, only E. coli SB278/94 from a bovine specimen was positive (1/47) for gimB, which represents 2.1% of the bovine isolates. The ability of SB278/94 to adhere to and invade eukaryotic cells was confirmed by adherence and gentamicin-protection assays using HeLa cells. This is the first study that investigates for gimB in bovine, canine and feline E. coli isolates and shows E. coli from the intestinal-bovine samples harboring gimB.

Factores de riesgo de colonización por Enterococcus spp resistente a vancomicina en pacientes pediátricos hospitalizados con patología oncológica / Risk factor of intestinal colonization with vancomycin resistant Enterococcus spp in hospitalized pediatric patients with oncological disease

Background: The isolation of vancomycin-resistant Enterococcus spp (ERV) has increased significantly within the last few years, along with the risk of infection and dissemination of these bacteria. Our aim was to determine risk factors (RF) for intestinal colonization in hospitalized pediatric patients with oncological disease at Hospital de Niños Roberto del Río. Methods: Between January 2012 and December 2013 a transversal study was performed with 107 rectal swabs and processed with a PCR for ERV. The patients were classified as "colonized with ERV" and "not colonized with ERV" and we evaluated possible RF for intestinal colonization in both groups. Results: VRE colonization was found in 51 patients (52%). The median of time elapsed between oncological diagnosis and VRE colonization was 35 days. The significant RF associated with VRE colonization were days of hospitalization prior to study, neutropenia and treatment with antibiotics within 30 days prior to study and mucositis. Conclusions: According to the RF revealed in this study we may suggest prevention standards to avoid ERV colonization. This is the first investigation in our country in hospitalized pediatric patients with oncological disease and processed with a multiplex PCR for ERV, therefore it is a great contribution about this subject in Chile.

Introducción: El aislamiento de Enterococcus spp resistentes a vancomicina (ERV) ha presentado un incremento significativo en los últimos años, aumentando el riesgo de infección por esta bacteria y favoreciendo su diseminación. Nuestro objetivo es determinar los factores de riesgo (FR) de colonización intestinal de ERV en pacientes oncológicos internados en el Hospital de Niños Roberto del Río. Método: Entre enero de 2012 y diciembre de 2013 se realizó un estudio transversal de colonización rectal por ERV mediante muestras de hisopado rectal obtenidas en 107 pacientes efectuando RPC múltiple para ERV. Se dividió en grupo "portador" y "no portador" y se evaluó los posibles FR para colonización por ERV. Resultados: Se encontró colonización por ERV en 51 pacientes (52%). El tiempo transcurrido desde el diagnóstico oncológico y la colonización presentó una mediana de 35 días. Los FR encontrados con asociación significativa fueron el número de días de hospitalización previa, neutropenia, uso de antimicrobianos 30 días previos y mucositis. Conclusión: De acuerdo a los FR encontrados podemos sugerir medidas de prevención para colonización por ERV. Esta es la primera investigación realizada en nuestro país en pacientes oncológicos pediátricos y que utiliza la técnica de RPC múltiple para ERV, lo que permite un aporte significativo sobre este tema en Chile.