Coronavirus fear of contagion and compliance with social distancing measures: evidence for a sample of a Spanish university community.

Background: Social distancing measures have been one of the core pillars of the strategy against COVID-19 in all the countries. This study aims at understanding what motivates behaviours and compliance with social distancing measures among students and workers from a Spanish public university. Methods: We carry out two logistics models considering two different dependent variables: not maintaining social relation with non-cohabiting people and not to leave home except for emergencies (n = 507, sample is formed by students and workers from the University of Cantabria in the North of Spain). Results: Being very concerned about getting ill suggests higher risk of not maintaining social relation with non-cohabiting people. Getting older increase the probability of not leaving home except for emergencies as happens with those who are very concerned about getting ill. Young people often living with vulnerable older relatives may affect students' behaviour. Conclusions: Our findings suggest that compliance with social distancing measures depends on several factors related to age, the number or kind of cohabiting people and level of concern about getting ill. Policies should address all these factors through a multidisciplinary perspective.

Change in eating habits during the Spanish COVID-19 pandemic lockdown: evidence for a sample of university community.

Background: The stress and anxiety caused by COVID-19 lockdown may have changed the eating habits of the population. Our aim is to assess the eating changes that have taken place due to the pandemic. Methods: Data were collected through an electronic survey created by the Health Economics Research Group of the University of Cantabria and IDIVAL and conducted between 14/01/2021 and 19/02/2021. A total of 1,417 responses were recorded, but only 507 complete observations were considered. We carried out a cross-sectional analysis through ordered probit regressions. Results: The improvement in post-confinement eating habits is associated with higher income level, better self-assessed health status and more physical activity. The worsening of eating habits is associated with having a certain level of nomophobia or the fear of contagion. Conclusions: Our analysis can be used for designing and implementing new strategies to overcome the negative spill overs of the COVID-19 pandemic and improve the dietary patterns.

Have Health Inequalities Increased during the COVID-19 Pandemic? Evidence from Recent Years for Older European Union Citizens.

Reducing inequality is one of the current challenges that most societies are facing. Our aim was to analyze the evolution of inequalities in self-assessed health among older Europeans in a time period spanning the 2008 economic crisis and the COVID-19 health crisis. We used data from Waves 2, 4 and 8 of the Survey of Health, Ageing and Retirement in Europe. We used inequality indices that accept ordinal variables. Our empirical results suggest that average inequality declines over time. Gender significantly influences the results. Some of the countries with the highest level of inequality are Denmark and Sweden, and some with the lowest are Estonia and the Netherlands. Our results may be of interest for the development of public policies to reduce inequalities. Special attention should be paid to vulnerable groups, such as the elderly.

Identification of Pneumococcal Serotypes by PCR-Restriction Fragment Length Polymorphism.

Streptococcus pneumoniae shows more than 90 capsular serotypes that can be distinguished by their reactivity against antisera. The main objective of this work was the development of a molecular method for serotyping without the use of antisera. A computer program containing an algorithm was used to search in a database for potentially useful enzymes for Restriction Fragment Length Polymorphism-RFLP typing, in order to maximize the discrimination between different serotypes. DNA sequences of 90 serotypes for the region between dexB and aliA genes were compiled, and a computer screening of restriction enzymes was performed. The wzg-wzh-wzd-wze region and Sse9I restriction predicted unique PCR-RFLP patterns for 39 serotypes and eight serogroups. A second restriction enzyme resolved fragment specific patterns for 25 serotypes. The method was tested with 98 serotype-unknown clinical isolates. PCR-RFLP analysis deduced correct serotypes that were confirmed by Quellung reaction for 78.5% of the isolates.

The effects of Bifidobacterium breve on immune mediators and proteome of HT29 cells monolayers.

The use of beneficial microorganisms, the so-called probiotics, to improve human health is gaining popularity. However, not all of the probiotic strains trigger the same responses and they differ in their interaction with the host. In spite of the limited knowledge on mechanisms of action some of the probiotic effects seem to be exerted through maintenance of the gastrointestinal barrier function and modulation of the immune system. In the present work, we have addressed in vitro the response of the intestinal epithelial cell line HT29 to the strain Bifidobacterium breve IPLA20004. In the array of 84 genes involved in inflammation tested, the expression of 12 was modified by the bifidobacteria. The genes of chemokine CXCL6, the chemokine receptor CCR7, and, specially, the complement component C3 were upregulated. Indeed, HT29 cells cocultivated with B. breve produced significantly higher levels of protein C3a. The proteome of HT29 cells showed increased levels of cytokeratin-8 in the presence of B. breve. Altogether, it seems that B. breve IPLA20004 could favor the recruitment of innate immune cells to the mucosa reinforcing, as well as the physical barrier of the intestinal epithelium.

Catabolism of glucose and lactose in Bifidobacterium animalis subsp. lactis, studied by 13C Nuclear Magnetic Resonance.

Bifidobacteria are widely used as probiotics in several commercial products; however, to date there is little knowledge about their carbohydrate metabolic pathways. In this work, we studied the metabolism of glucose and lactose in the widely used probiotic strain Bifidobacterium animalis subsp. lactis BB-12 by in vivo (13)C nuclear magnetic resonance (NMR) spectroscopy. The metabolism of [1-(13)C]glucose was characterized in cells grown in glucose as the sole carbon source. Moreover, the metabolism of lactose specifically labeled with (13)C on carbon 1 of the glucose or the galactose moiety was determined in suspensions of cells grown in lactose. These experiments allowed the quantification of some intermediate and end products of the metabolic pathways, as well as determination of the consumption rate of carbon sources. Additionally, the labeling patterns in metabolites derived from the metabolism of glucose specifically labeled with (13)C on carbon 1, 2, or 3 in cells grown in glucose or lactose specifically labeled in carbon 1 of the glucose moiety ([1-(13)Cglucose]lactose), lactose specifically labeled in carbon 1 of the galactose moiety ([1-(13)Cgalactose]lactose), and [1-(13)C]glucose in lactose-grown cells were determined in cell extracts by (13)C NMR. The NMR analysis showed that the recovery of carbon was fully compatible with the fructose 6-phosphate, or bifid, shunt. The activity of lactate dehydrogenase, acetate kinase, fructose 6-phosphate phosphoketolase, and pyruvate formate lyase differed significantly between glucose and lactose cultures. The transcriptional analysis of several putative glucose and lactose transporters showed a significant induction of Balat_0475 in the presence of lactose, suggesting a role for this protein as a lactose permease. This report provides the first in vivo experimental evidence of the metabolic flux distribution in the catabolic pathway of glucose and lactose in bifidobacteria and shows that the bifid shunt is the only pathway involved in energy recruitment from these two sugars. On the basis of our experimental results, a model of sugar metabolism in B. animalis subsp. lactis is proposed.

Factors involved in the colonization and survival of bifidobacteria in the gastrointestinal tract.

Probiotics are live microorganisms that when administered in adequate amounts confer a health benefit on the host. They are mainly bacteria from the genera Lactobacillus and Bifidobacterium. Traditionally, functional properties of lactobacilli have been studied in more detail than those of bifidobacteria. However, many recent studies have clearly revealed that the bifidobacterial population in the human gut is far more abundant than the population of lactobacilli. Although the 'beneficial gut microbiota' still remains to be elucidated, it is generally believed that the presence of bifidobacteria is associated with a healthy status of the host, and scientific evidence supports the benefits attributed to specific Bifidobacterium strains. To carry out their functional activities, bifidobacteria must be able to survive the gastrointestinal tract transit and persist, at least transiently, in the host. This is achieved using stress response mechanisms and adhesion and colonization factors, as well as by taking advantage of specific energy recruitment pathways. This review summarizes the current knowledge of the mechanisms involved in facilitating the establishment, colonization, and survival of bifidobacteria in the human gut.

Role of extracellular transaldolase from Bifidobacterium bifidum in mucin adhesion and aggregation.

The ability of bifidobacteria to establish in the intestine of mammals is among the main factors considered to be important for achieving probiotic effects. The role of surface molecules from Bifidobacterium bifidum taxon in mucin adhesion capability and the aggregation phenotype of this bacterial species was analyzed. Adhesion to the human intestinal cell line HT29 was determined for a collection of 12 B. bifidum strains. In four of them-B. bifidum LMG13195, DSM20456, DSM20239, and A8-the involvement of surface-exposed macromolecules in the aggregation phenomenon was determined. The aggregation of B. bifidum A8 and DSM20456 was abolished after treatment with proteinase K, this effect being more pronounced for the strain A8. Furthermore, a mucin binding assay of B. bifidum A8 surface proteins showed a high adhesive capability for its transaldolase (Tal). The localization of this enzyme on the surface of B. bifidum A8 was unequivocally demonstrated by immunogold electron microscopy experiments. The gene encoding Tal from B. bifidum A8 was expressed in Lactococcus lactis, and the protein was purified to homogeneity. The pure protein was able to restore the autoaggregation phenotype of proteinase K-treated B. bifidum A8 cells. A recombinant L. lactis strain, engineered to secrete Tal, displayed a mucin- binding level more than three times higher than the strain not producing the transaldolase. These findings suggest that Tal, when exposed on the cell surface of B. bifidum, could act as an important colonization factor favoring its establishment in the gut.

Interaction of Bifidobacterium bifidum LMG13195 with HT29 cells influences regulatory-T-cell-associated chemokine receptor expression.

Probiotics play an important role in the maintenance of the gastrointestinal barrier. In addition to direct effects on mucosal integrity, the interaction with the intestinal mucosa may have an active immunoregulatory effect. In the present work, we exposed HT29 intestinal epithelial cells to two Bifidobacterium species to determine their effect on gene expression profile, enterocyte monolayer integrity, and T-cell response. Bifidobacterium breve IPLA 20004 triggered a more pronounced increase in the transepithelial resistance of the enterocyte monolayer than Bifidobacterium bifidum LMG13195. The transcriptome profile of HT29 cells cultured in the presence of B. bifidum LMG13195 showed an increased expression of immune mediators and, interestingly, chemotactic molecules (CXCL10, CCL20, CXCL11 and CCL22) able to recruit lymphocytes. Since regulatory T cells (Treg cells) may express receptors for specific chemokines, we cultured peripheral blood mononuclear cells with supernatants of HT29 cells previously treated with Bifidobacterium strains and analyzed FOXP3 and CD25 Treg markers and CCR6, CXCR3, CCR4, and CCR3 expression on CD4(+) lymphocytes. The proportion of CD25(high) FOXP3(+) cells was significantly increased after culture with B. bifidum LMG13195-conditioned HT29 supernatant. Moreover, this treatment led to the largest amount of CCR6(+) CXCR3(-) CCR4(+) CCR3(+) CD4(+) cells expressing high levels of CD25, corresponding to the Treg population. These results suggest that soluble factors secreted after B. bifidum LMG13195 contact with intestinal epithelial cells favored the generation of CD4(+) CD25(high) lymphocytes expressing chemokine receptor Treg markers, thus making possible their recruitment to the intestinal mucosa.

Treg-inducing membrane vesicles from Bifidobacterium bifidum LMG13195 as potential adjuvants in immunotherapy.

Allergen-specific immunotherapy is the only treatment shown to induce antigen-specific regulatory T (Treg) cells and peripheral tolerance to restore human homeostasis. Specific probiotic strains are valid candidates to improve the allergen-specific tolerance, since they are able to generate Treg cells from naïve precursors. We recently reported that exposing dendritic cells (DCs) to Bifidobacterium bifidum LMG13195 in vitro induced the polarization of naïve T cells into functional Treg cells. In the present study, we evaluated the ability of DCs exposed to different B. bifidum subcellular fractions to promote Treg differentiation. We found that DCs exposed to B. bifidum LMG13195 membrane vesicles most strongly promoted differentiation of functional CD25(high)FOXP3(high)CD127(-/low) Treg cells as well as induced the highest IL-10 levels respect to the proinflammatory cytokines IFNγ, TNFα and IL-17. Our results suggest the potential use of B. bifidum LMG13195 membrane vesicles as a safe and clinically effective adjuvant for immunotherapy.

Immune response to Bifidobacterium bifidum strains support Treg/Th17 plasticity.

In this work we analyzed the immune activation properties of different Bifidobacterium strains in order to establish their ability as inductors of specific effector (Th) or regulatory (Treg) responses. First, we determined the cytokine pattern induced by 21 Bifidobacterium strains in peripheral blood mononuclear cells (PBMCs). Results showed that four Bifidobacterium bifidum strains showed the highest production of IL-17 as well as a poor secretion of IFNγ and TNFα, suggesting a Th17 profile whereas other Bifidobacterium strains exhibited a Th1-suggestive profile. Given the key role of Th17 subsets in mucosal defence, strains suggestive of Th17 responses and the putative Th1 Bifidobacterium breve BM12/11 were selected to stimulate dendritic cells (DC) to further determine their capability to induce the differentiation of naïve CD4(+) lymphocytes toward different Th or Treg cells. All selected strains were able to induce phenotypic DC maturation, but showed differences in cytokine stimulation, DC treated with the putative Th17 strains displaying high IL-1ß/IL-12 and low IL-12/IL-10 index, whereas BM12/11-DC exhibited the highest IL-12/IL-10 ratio. Differentiation of naïve lymphocytes confirmed Th1 polarization by BM12/11. Unexpectedly, any B. bifidum strain showed significant capability for Th17 generation, and they were able to generate functional Treg, thus suggesting differences between in vivo and vitro responses. In fact, activation of memory lymphocytes present in PBMCS with these bacteria, point out the presence in vivo of specific Th17 cells, supporting the plasticity of Treg/Th17 populations and the key role of commensal bacteria in mucosal tolerance and T cell reprogramming when needed.

A flagellin-producing Lactococcus strain: interactions with mucin and enteropathogens.

Bacillus cereus CH is a probiotic strain used in human nutrition whose adhesion to mucin is dependent on its surface-associated flagellin. Flagellins from the surface of several probiotic Bacillus strains were efficiently extracted with 5 M LiCl and identified by peptide fingerprinting. Based on the proteomic analysis, cloning of the gene coding for the flagellin of B. cereus CH was performed in the lactococcal vector pNZ8110 under the control of a nisin-inducible promoter. The resulting strain, Lactococcus lactis CH, produced a surface-associated flagellin after 6 h of induction with nisin. The recombinant Lactococcus strain adhered strongly to mucin-coated polystyrene plates, whilst inhibiting competitively the adhesion of the pathogens Escherichia coli LMG2092 and Salmonella enterica ssp. enterica LMG15860 to the same molecule. Strain CH could be used in further experimentation for the characterization of the molecular mechanism of action of this probiotic B. cereus CH flagellin.

Oriented immobilization of anti-pneumolysin tagged recombinant antibody fragments.

Recombinant antibodies such as Fab and scFv are monovalent and small in size, although their functional affinity can be improved through tag-specific immobilization. In order to find the optimum candidate for oriented immobilization, we generated Fab and scFv fragments derived from an anti-pneumolysin monoclonal antibody PLY-7, with histidine and cysteine residues added in diverse arrangements. Tagged antibody fragments scFv-Cys7-His6, His6-scFv-Cys7, and Fab-Cys7 lost considerable affinity for the antigen; however, Fab-His6, Fab-Cys1, and scFv-His6-Cys1 were able to detect immobilized antigen, revealing that the position and number of histidine and cysteine residues are involved differently in the reactivity of antibody fragments. Random and orientated immobilizations were carried out using conventional polystyrene and commercial surface-pretreated ELISA plates. The best orientation performance was obtained with Fab-Cys1-biotin on streptavidin-coated plates with increased signal levels of 62%, while oriented immobilization of Fab-His6 and scFv-His6-Cys1 on nickel- and maleimide-coated plates failed to improve the ELISA sensitivity.