Letteratura scientifica selezionata sul tema "Bifidobacteriaceae"

Gut microbiome development affects infant health and postnatal physiology. The gut microbe assemblages of preterm infants have been reported to be different from that of healthy term infants. However, the patterns of ecosystem development and inter-individual differences remain poorly understood. We investigated hospitalised preterm infant gut microbiota development using 16S rRNA gene amplicons and the metabolic profiles of 268 stool samples obtained from 17 intensive care and 42 term infants to elucidate the dynamics and equilibria of the developing microbiota. Infant gut microbiota were predominated by Gram-positive cocci, Enterobacteriaceae or Bifidobacteriaceae, which showed sequential transitions to Bifidobacteriaceae-dominated microbiota. In neonatal intensive care unit preterm infants (NICU preterm infants), Staphylococcaceae abundance was higher immediately after birth than in healthy term infants, and Bifidobacteriaceae colonisation tended to be delayed. No specific NICU-cared infant enterotype-like cluster was observed, suggesting that the constrained environment only affected the pace of transition, but not infant gut microbiota equilibrium. Moreover, infants with Bifidobacteriaceae-dominated microbiota showed higher acetate concentrations and lower pH, which have been associated with host health. Our data provides an in-depth understanding of gut microbiota development in NICU preterm infants and complements earlier studies. Understanding the patterns and inter-individual differences of the preterm infant gut ecosystem is the first step towards controlling the risk of diseases in premature infants by targeting intestinal microbiota.

ABSTRACT Bifidobacteriaceae were isolated from saliva and infected dentine by using a mupirocin-based selective medium. Of the saliva samples, 94% harbored bifids. The mean concentration (± the standard error) was 4.46 (±0.12) log10(CFU per ml + 1), and the predominant isolates were Bifidobacterium dentium, B. longum, Scardovia inopinata, Parascardovia denticolens, and Alloscardovia omnicolens.

Gut microbiota affects the host’s metabolism, and it is suggested that there are differences in gut microbiota composition between patients with type 2 diabetes and healthy individuals. Additionally, dysbiosis may increase the concentration of lipopolysaccharides (LPS), causing metabolic endotoxemia, which induces impaired glucose tolerance. Several studies have reported relationships between metabolic diseases and the gut microbiota; and prebiotics, such as oligosaccharides, are commonly consumed to regulate gut microbiotas in healthy individuals. Galacto-oligosaccharides (GOS) are a major prebiotic, which specifically increase Bifidobacteriaceae abundance. Recent studies have reported that Bifidobacteriaceae improved metabolic endotoxemia or impaired glucose tolerance. However, there are few studies reporting the effects of GOS on patients with type 2 diabetes. In the current study, we compared clinical parameters, faecal gut microbiota, their associated metabolic products and their components such as LPS, and LPS-binding protein (LBP) produced by the host, between patients with diabetes and healthy controls. We then assessed the effects of GOS on glycaemic control, and gut microbiotas and metabolites in patients with type 2 diabetes in a double-blind controlled manner. LBP levels were significantly higher in patients with diabetes than those of healthy subjects, which was consistent with previous reports. The abundance of Bifidobacteriaceae and the diversity of intestinal microbiota were significantly lower in patients with diabetes than in healthy subjects. Interestingly, Bifidobacteriaceae was markedly restored in patients with diabetes after consumption of GOS, whereas LBP and glucose tolerance did not improve during this short-term trial period. In the present study, we demonstrated that GOS can ameliorate dysbiosis in patients with diabetes, and continuous intake of GOS may be a promising method for managing type 2 diabetes.

The validated SHIME model was used to assess the effect of repeated administration of two different lactulose dosages (5 g/d and 10 g/d) on the human gut microbiome during and following amoxicillin–clavulanic acid treatment. First, antibiotic treatment strongly decreased Bifidobacteriaceae levels from 54.4% to 0.6% and from 23.8% to 2.3% in the simulated proximal and distal colon, respectively, coinciding with a marked reduction in butyrate concentrations. Treatment with lactulose enhanced acetate and lactate levels during antibiotic treatment, likely through lactulose fermentation by Lachnospiraceae and Lactobacillaceae. One week after cessation of antibiotic treatment, Bifidobacteriaceae levels re-increased to 20.4% and 7.6% in the proximal and distal colon of the 5 g lactulose/d co-administered unit, as compared with 1.0% and 2.2% in the antibiotic-treated unit, and were even further stimulated upon extension of lactulose administration. Marked butyrogenic effects were observed upon prolonged lactulose supplementation, suggesting the establishment of cross-feeding interactions between Bifidobacteriaceae and butyrate producers. Furthermore, a limited Enterobacteriaceae outgrowth following antibiotic treatment was observed upon dosing with 10 g lactulose/d, indicating inhibition of pathogenic colonization by lactulose following antibiotic therapy. Overall, lactulose seems to be an interesting candidate for limiting the detrimental effects of amoxicillin–clavulanic acid on the human gut microbiome, though further studies are warranted to confirm these findings.

Abstract Gut microbiota (GM) is a crucial underlying player during sepsis pathogenesis. However, the causal relationship is unclear and remains to be determined. A two-sample Mendelian randomization study was implemented. The statistical data about sepsis together with GM summarized from genome-wide association studies were evaluated. Instrumental variables were defined as single-nucleotide polymorphisms with prominent correlations with exposure. The inverse-variance-weighted test was employed as a major approach of Mendelian randomization analysis to estimate of causal relationships. The inverse-variance-weighted analysis results demonstrated that at different taxa levels, Actinobacteria and Bifidobacteriaceae influence sepsis. Actinobacteria had negative relationships to sepsis risk at the phylum (β = –0.34, SE = 0.10, p = 0.0008) and class (β = –0.23, SE = 0.07, p = 0.0011) levels in outcome coded ieu-b-69. Actinobacteria at the phylum level (β = –0.22, SE = 0.10, p = 0.027) was also negatively associated with sepsis in outcome coded ieu-b-4980. Bifidobacteriaceae at the order (β = –0.20, SE = 0.06, p = 0.0021), family (β = –0.20, SE = 0.06, p = 0.0021), and genus (β = –0.20, SE = 0.06, p = 0.0007) levels were all negatively correlated with the risk of sepsis in outcome coded ieu-b-69. The results of the Wald ratio model showed that Tyzzerella genus (OR (95%CI) = 0.6902[0.4907,0.9708], p = 0.0331) and Gastranaerophilales order (OR (95%CI) = 0.5907[0.3516,0.9926], p = 0.0468) were negatively connected with sepsis. This study implied at different taxa levels Actinobacteria and Bifidobacteriaceae, Tyzzerella genus, and Gastranaerophilales order have a causal relationship with sepsis, indicating that they are protective factors for the incidence of sepsis.

Objective: The aims of this study are as follows: (1) to understand the relationship between gut microbiota and the choking phenomenon in diving athletes, and (2) to regulate the gut microbiota in diving athletes by drinking yogurt containing Bifidobacterium animalis subsp. lactis BB-12 and observe changes in the choking phenomenon in diving athletes. Methods: Experiment 1: A total of 20 diving athletes were tested in low- and high-pressure situations. Gut microbiota (n = 18) composition was then determined and differences in the gut microbiota composition among diving athletes who presented choking vs. no choking were identified. Experiment 2: A total of 16 divers who presented choking were divided into a high yogurt group (n = 6) and a low yogurt group (n = 10) for 15 days. Results: (1) The content of Veillonellaceae in divers who presented choking was significantly higher when compared to divers who did not present choking (p < 0.05). Bifidobacteriaceae (r = −0.52, p < 0.05) and Lactobacillaceae (r = −0.66, p < 0.05) were negatively correlated with the choking index. (2) During experiment 2, the average daily intake of the high yogurt group was 611.78 ± 94.94 mL and the average daily intake of the low yogurt group was 338 ± 71.45 mL and the abundance of Bifidobacteriaceae was significantly higher in the high yogurt group than in the low yogurt group. After the experiment, the choking index in the high yogurt group became significantly lower than that of the low yogurt group (z = −3.26, p < 0.001). Conclusion: The intake of yogurt containing B. animalis subsp. lactis can increase the abundance of Bifidobacteriaceae in elite diving athletes and their performance under high pressure. Hence, gut microbiota may affect the choking phenomenon in elite diving athletes.

Background: Regular exercise has been described to modify both the diversity and the relative abundance of certain bacterial taxa. To our knowledge, the effect of a cycling stage race, which entails extreme physiological and metabolic demands, on the gut microbiota composition and its metabolic activity has not been analysed. Objective: The aim of this cohort study was to analyse the dynamics of faecal microbiota composition and short-chain fatty acids (SCFAs) content of professional cyclists over a Grand Tour and their relationship with performance and dietary intake. Methods: 16 professional cyclists competing in La Vuelta 2019 were recruited. Faecal samples were collected at four time points: the day before the first stage (A); after 9 stages (B); after 15 stages (C); and on the last stage (D). Faecal microbiota populations and SCFA content were analysed using 16S rRNA sequencing and gas chromatography, respectively. A principal component analysis (PCA) followed by Generalised Estimating Equation (GEE) models were carried out to explore the dynamics of microbiota and SCFAs and their relationship with performance. Results: Bifidobacteriaceae, Coriobacteriaceae, Erysipelotrichaceae, and Sutterellaceae dynamics showed a strong final performance predictive value (r = 0.83, ranking, and r = 0.81, accumulated time). Positive correlations were observed between Coriobacteriaceae with acetate (r = 0.530) and isovalerate (r = 0.664) and between Bifidobacteriaceae with isobutyrate (r = 0.682). No relationship was observed between SCFAs and performance. The abundance of Erysipelotrichaceae at the beginning of La Vuelta was directly related to the previous intake of complex-carbohydrate-rich foods (r = 0.956), while during the competition, the abundance of Bifidobacteriaceae was negatively affected by the intake of simple carbohydrates from supplements (r = −0.650). Conclusions: An ecological perspective represents more realistically the relationship between gut microbiota composition and performance compared to single-taxon approaches. The composition and periodisation of diet and supplementation during a Grand Tour, particularly carbohydrates, could be designed to modulate gut microbiota composition to allow better performance.

Gut microbiota are reported to be associated with many diseases, including cancers. Several bacterial taxa have been shown to be associated with cancer development or response to treatment. However, longitudinal microbiota alterations during the development of cancers are relatively unexplored. To better understand how microbiota changes, we profiled the gut microbiota composition from prostate cancer-bearing mice and control mice at five different time points. Distinct gut microbiota differences were found between cancer-bearing mice and control mice. Akkermansiaceae was found to be significantly higher in the first three weeks in cancer-bearing mice, which implies its role in the early stage of cancer colonization. We also found that Bifidobacteriaceae and Enterococcaceae were more abundant in the second and last sampling week, respectively. The increments of Akkermansiaceae, Bifidobacteriaceae and Enterococcaceae were previously found to be associated with responses to immunotherapy, which suggests links between these bacteria families and cancers. Additionally, our function analysis showed that the bacterial taxa carrying steroid biosynthesis and butirosin and neomycin biosynthesis were increased, whereas those carrying naphthalene degradation decreased in cancer-bearing mice. Our work identified the bacteria taxa altered during prostate cancer progression and provided a resource of longitudinal microbiota profiles during cancer development in a mouse model.

We examined the prebiotic potential of 32 food ingredients on the developing infant microbiome using an in vitro gastroileal digestion and colonic fermentation model. There were significant changes in the concentrations of short-chain fatty-acid metabolites, confirming the potential of the tested ingredients to stimulate bacterial metabolism. The 16S rRNA gene sequencing for a subset of the ingredients revealed significant increases in the relative abundances of the lactate- and acetate-producing Bifidobacteriaceae, Enterococcaceae, and Lactobacillaceae, and lactate- and acetate-utilizing Prevotellaceae, Lachnospiraceae, and Veillonellaceae. Selective changes in specific bacterial groups were observed. Infant whole-milk powder and an oat flour enhanced Bifidobacteriaceae and lactic acid bacteria. A New Zealand-origin spinach powder enhanced Prevotellaceae and Lachnospiraceae, while fruit and vegetable powders increased a mixed consortium of beneficial gut microbiota. All food ingredients demonstrated a consistent decrease in Clostridium perfringens, with this organism being increased in the carbohydrate-free water control. While further studies are required, this study demonstrates that the selected food ingredients can modulate the infant gut microbiome composition and metabolism in vitro. This approach provides an opportunity to design nutrient-rich complementary foods that fulfil infants’ growth needs and support the maturation of the infant gut microbiome.

Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista
INTRODUCCIÓN: La caries dental es una enfermedad crónica compleja y multifactorial, de componente infeccioso y de alta prevalencia en el ser humano. Se desarrolla producto de la interacción en el tiempo de una producción de ácidos a partir del metabolismo bacteriano, los dientes y la saliva. La microbiota que interactúa en este proceso es muy diversa. Estudios recientes han identificado a miembros de la familia Bifidobacteriaceae como microorganismos participantes de este proceso. Estos estudios son, en su mayoría, en adultos, y no existen análisis que relacionen estos microorganismos con niños. Por otra parte, las bacterias cariogénicas deben presentan mecanismos de patogenicidad para producir la enfermedad, entre los que se han descrito la aciduria, acidogénesis y la adhesión, todas codificadas por genes. En el presente estudio se buscará la presencia de estos mecanismos a partir de los genes ldh, gadB y spaA. OBJETIVO: Determinar la presencia de miembros de la familia Bifidobacteriaceae en saliva y caries de niños Chilenos entre 7 y 11 años de edad y analizar los genes que codifican para los factores de virulencia ldh, gadB y spaA. METODOLOGÍA: Mediante examen clínico, se seleccionó un grupo de 18 niños, 9 niños sin experiencia de caries y 9 con experiencia de caries. Se tomaron muestras de saliva de ambos grupos y muestras de sitio con caries en dentina a niños con experiencia de caries. Se procedió a realizar cultivos en medio MTPY, selectivo para Bifidobacteriaceae. Se aisló ADN genómico desde aislados clínicos seleccionados al azar, se realizó PCR para amplificar un fragmento del ADN del gen 16S ARNr y fueron enviados para su secuenciación. El análisis de estas secuencias permitió identificar las especies presentes en cada muestra. La presencia de los factores de virulencia se realizó por PCR, utilizando partidores específicos para cada gen en análisis (ldh, gadB y spaA). RESULTADOS: Se detectó Parascardovia denticolens, miembro de la familia Bifidobacteriaceae, en el 5,6% de los niños estudiados (n=18). Mediante PCR se determinó que de los aislados clínicos obtenidos, el 50% dió positivo para el factor de virulencia ldh mientras que para los factores de virulencia gadB y spaA no fue posible obtener un amplificado positivo. No se obtuvieron aislados clínicos para otras especies de Bifidobacteriaceae. La especie Actinomyces odontolyticus fue encontrada abundantemente en muestras de saliva del grupo de niños con experiencia de caries y sin experiencia de caries. Se determinó una asociación estadísticamente significativa de este microorganismo a las muestras de saliva de ambos grupos, al comparar con su presencia en los sitios con caries (p=0,01 y p=0,001). Rothia mucilaginosa se encontró asociada a las muestras de saliva en ausencia de experiencia de caries al comparar con su presencia en sitios con caries (p=0,001). CONCLUSIONES: En niños Chilenos entre 7 y 11 años sólo fue posible detectar la presencia de P. denticolens desde sitios con caries, única especie de los siete géneros de la familia Bifidobacteriaceae. Los aislados clínicos de P. denticolens codifican el gen Idh en un 50% de los aislados, mientras que no codifican para los genes spaA y gadB, por lo que estos aislados no usarían estos mecanismos descritos para la adhesión y resistencia de ambientes ácidos. Se encontraron otras especies bacterianas asociadas al tipo de muestra, como A. odontolyticus encontrada en saliva tanto de niños libres de caries como con experiencia de caries. De este mismo modo existen especies bacterianas relacionadas a la ausencia de caries, como R. mucilaginosa.
Adscrito a Proyecto U-inicia difarp 40/13, VID, U. de Chile

Introduction : Les maladies inflammatoires chroniques de l'intestin (MICI) sont un problème important en santé publique associées à des changements dans la composition et la fonctionnalité du microbiote intestinal, avec notamment l'appauvrissement en bactéries anaérobies strictes. Cependant, il y a moins d'évidence pour les bifidobactéries. Ici, par une approche culturomique, nous avons caractérisé la diversité taxonomique, génétique et fonctionnelle des bifidobactéries isolées du microbiote fecal de patients atteints de MICI, en phase active ou non active de la maladie, et évalué leur potentiel probiotique.Résultats : Un total de 341 bifidobactéries ont été isolées de matières fécales de 78 patients atteints de MICI. Le microbiote MICI est enrichi en B. dentium (27% des bifidobactéries isolées), particulièrement dans la rectocolite hémorragique (39%) et en B. adolescentis (26%), surtout dans la maladie de Crohn active (40%). Nous avons également soulevé l'influence du traitement immunosuppresseur et l'âge des patients sur la diversité taxonomique des bifidobactéries. Des souches potentiellement probiotiques ont été identifiées chez des patients atteints de MICI en phase active et non active, avec peu de corrélations à l'origine d'isolement. Des souches de B. longum ont été retenues comme présentant le plus grand potentiel probiotique de part leur synthèse d'exopolysaccharides, activités antibactériennes et capacités anti-inflammatoires. B. adolescentis, B. dentium et B. angulatum ont également montré un potentiel probiotique, en particulier dans l'axe intestin-cerveau. De plus, nous avons mis en évidence une faible diversité génétique intra-espèce dans les souches isolées d'un même patient, mais parfois avec des différences fonctionnelles in vitro (corrélées, au moins en partie, à des marqueurs de transfert horizontal de gènes ou des polymorphismes nucléotidiques). Conclusions : Les profils taxonomiques diffèrent dans le microbiote des patients atteints de MICI selon le type et l'activité de la pathologie, mais tous sont enrichis en B. dentium et B. adolescentis. Les bifidobactéries présentant un potentiel probiotique (en particulier des souches de B. longum) ont été isolées de patients atteints de MICI, autant en phase active que non active de la maladie
Introduction: Inflammatory Bowel Diseases (IBD) are a major public health issue associated to changes in the composition and functionality of the intestinal microbiota, including the depletion of strict anaerobes. Nevertheless, less evidence exists for bifidobacteria. Here, we characterized the taxonomic, genetic and functional diversity of bifidobacteria isolated from human fecal microbiota in active and non-active IBD patients by a culturomics approach and evaluated their potential as probiotics in gut health.Results: A total of 341 bifidobacteria were isolated from fecal material of 78 IBD patients. IBD microbiota was enriched in Bifidobacterium dentium (27% of isolated bifidobacteria), specially in active and nonactive ulcerative colitis (39%) and B. adolescentis (26%), particularly in active Crohn's disease (40%). The immunosuppressive treatment and age of patients also influenced the taxonomic diversity of bifidobacteria in the IBD microbiota. Strains with potential probiotic characteristics were identified in both active and non-active IBD patients, with only few correlations to the isolation origin. B. longum were retained asstrains with highest probiotic potential by their exopolysaccharide synthesis, antibacterial activity, and anti-inflammatory capacity. B. adolescentis, B. dentium and B. angulatum also showed probiotic potential, mainly in the gut-brain axis. Furthermore, we highlighted low genetic intra-species diversity in strains isolated from the same patient, but with in vitro functional differences in some cases (correlated, at least partially, to markers of horizontal gene transfer or single nucleotide polymorphisms). Conclusions: Different taxonomic profiles were identified in the microbiota of IBD patients according to the type and activity of pathology but all were enriched in B. dentium and B. adolescentis. We isolated bifidobacteria with probiotic potential, especially B. longum strains, in both active and non-active IBD