Arancha Llama-Palacios

: This study explores the microbiota and metabolite profile of raw cow’s milk, analyzing the correlation between them and their potential impact on consumer health, focusing on factors like cow’s feeding regimen (conventional vs. grazing), the herd’s geographical location (coastal vs. inland), and the thermal stability of raw milk samples. To achieve this, raw milk quality was assessed through mesophilic bacterial count and thermal stability using the 70° and 80° ethanol test. Metataxonomic analysis was performed using Illumina 16S rRNA hypervariable region sequencing, and untargeted metabolomics was conducted using UHPLC-Q/TOF MS/MS, followed by multivariate correlation analysis. All samples met quality standards. A total of 1258 prokaryotic ASVs were identified, spanning 48 bacterial phyla and one archaeal phylum, with 909 genera and 349 unidentified ASVs. Additionally, 70 metabolites were identified, including essential amino acids, vitamins, and bioactive compounds with antimicrobial, anti-inflammatory, and prebiotic properties. Significant correlations between bacterial diversity and metabolite profiles were observed. Feeding regimen and geographical location influence microbial composition and metabolite abundance, while thermal stability was linked to specific metabolites like oleamide and pyridoxal. These findings suggest that microbiota-derived metabolites can enhance the nutritional and functional value of milk. Further research is needed to understand how environmental and processing factors influence these dynamics.

Small intestinal bacterial overgrowth (SIBO) is a functional digestive disorder whose incidence has been acknowledged by several medical associations, such as the American Gastroenterological Association. It is estimated that between 14% and 40% of patients diagnosed with irritable bowel syndrome also have SIBO, highlighting the importance of accurate diagnosis to enable effective treatment plans. Nutrition and diet therapy play a pivotal role in SIBO management, not only in alleviating symptoms but also in preventing relapses. The objective of this review is to gather updated information on dietary management for SIBO to define the role of the dietitian and determine the most suitable nutritional therapy based on scientific evidence. The review will encompass various strategies, ranging from specific diets to dietary supplements, as well as the potential contribution of dietary treatment to improving SIBO.

Scientific evidence regarding the effectiveness of vitamin and mineral supplements in healthy individuals remains scarce. In a randomized, double-blind study, 30 healthy individuals were assigned to receive a single daily dose of multivitamin and multimineral supplementation or a double daily dose for 30 days. Before and after the intake, an untargeted metabolomics assay for serum metabolites was conducted by hydrophilic interaction liquid chromatography–mass spectrometry, and clinical assessments of peripheral blood samples were performed. A paired t-test for metabolic analysis, adjusted using the false discovery rate (FDR) and p-value correction method (rate of change > 2 and FDR < 0.05), the Shapiro–Wilk test, Student’s t-test, and the Mann–Whitney U test were applied depending on the variable, with a 5% significance level. An impact on oxidative stress was observed, with a significant reduction in homocysteine levels and an increment of pyridoxic acid (vitamin B6). The effect on energy metabolism was shown by a significant increase in diverse metabolites, such as linoleoylcarnitine. Serum iron and calcium levels were also impacted. Overall, we observed a nutritional balance compatible with a good state of health. In conclusion, beneficial effects on adult health were demonstrated in relation to oxidative stress, energy metabolism, and nutritional balance.

Scientific evidence has increasingly supported the beneficial effects of probiotic-based food supplements on human intestinal health. This ex vivo study investigated the effects on the composition and metabolic activity of the intestinal microbiota of three probiotic-based food supplements, containing, respectively, (1) Bifidobacterium longum ES1, (2) Lactobacillus acidophilus NCFM^®, and (3) a combination of L. acidophilus NCFM^®, Lactobacillus paracasei Lpc-37™, Bifidobacterium lactis Bi-07™, and Bifidobacterium lactis Bl-04™. This study employed fecal samples from six healthy donors, inoculated in a Colon-on-a-plate^® system. After 48 h of exposure or non-exposure to the food supplements, the effects were measured on the overall microbial fermentation (pH), changes in microbial metabolic activity through the production of short-chain and branched-chain fatty acids (SCFAs and BCFAs), ammonium, lactate, and microbial composition. The strongest effect on the fermentation process was observed for the combined formulation probiotics, characterized by the significant stimulation of butyrate production, a significant reduction in BCFAs and ammonium in all donors, and a significant stimulatory effect on bifidobacteria and lactobacilli growth. Our findings suggest that the combined formulation probiotics significantly impact the intestinal microbiome of the healthy individuals, showing changes in metabolic activity and microbial abundance as the health benefit endpoint.

Bacteria in the oral cavity, including commensals and opportunistic pathogens, are organized into highly specialized sessile communities, coexisting in homeostasis with the host under healthy conditions. A dysbiotic environment during biofilm evolution, however, allows opportunistic pathogens to become the dominant species at caries-affected sites at the expense of health-associated taxa. Combining tooth brushing with dentifrices or rinses combat the onset of caries by partially removes plaque, but resulting in the biofilm remaining in an immature state with undesirables’ consequences on homeostasis and oral ecosystem. This leads to the need for therapeutic pathways that focus on preserving balance in the oral microbiota and applying strategies to combat caries by maintaining biofilm integrity and homeostasis during the rapid phase of supragingival plaque formation. Adhesion, nutrition, and communication are fundamental in this phase in which the bacteria that have survived these adverse conditions rebuild and reorganize the biofilm, and are considered targets for designing preventive strategies to guide the biofilm towards a composition compatible with health. The present review summarizes the most important advances and future prospects for therapies based on the maintenance of biofilm integrity and homeostasis as a preventive measure of dysbiosis focused on these three key factors during the rapid phase of plaque formation.

The ecological dysbiosis of a biofilm includes not only bacterial changes but also changes in their metabolism. Related to oral biofilms, changes in metabolic activity are crucial endpoint, linked directly to the pathogenicity of oral diseases. Despite the advances in caries research, detailed microbial and metabolomic etiology is yet to be fully clarified. To advance this knowledge, a meta‐taxonomic approach based on 16S rRNA gene sequencing and an untargeted metabolomic approach based on an ultra‐high performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry analysis (UHPLC/Q‐TOF‐MS) were conducted. To this end, an in vitro biofilm model derived from the saliva of healthy participants were developed, under commensal and cariogenic conditions by adding sucrose as the disease trigger. The cariogenic biofilms showed a significant increase of Firmicutes phyla (p = 0.019), due to the significant increase in the genus Streptococcus (p = 0.010), and Fusobacter (p < 0.001), by increase Fusobacterium (p < 0.001) and Sphingomonas (p = 0.024), while suffered a decrease in Actinobacteria (p < 0.001). As a consequence of the shift in microbiota composition, significant extracellular metabolomics changes were detected, showed 59 metabolites of the 120 identified significantly different in terms of relative abundance between the cariogenic/commensal biofilms (Rate of change > 2 and FDR < 0.05). Forty‐two metabolites were significantly higher in abundance in the cariogenic biofilms, whereas 17 metabolites were associated significantly with the commensal biofilms, principally related protein metabolism, with peptides and amino acids as protagonists, latter represented by histidine, arginine, l‐methionine, glutamic acid, and phenylalanine derivatives.

Fusobacterium nucleatum is isolated from both supra‐ and sub‐gingival dental biofilms in humans and has been implicated in the aetiology of periodontitis. Also, this bacterium plays an important role in serious infections in other parts of the body. The aim of this investigation was to study the protein differential expression of F. nucleatum when growing on biofilm, compared to planktonic state, using proteomic analysis by the 2D‐DIGE™ system. In all, 68 proteins were differentially expressed during biofilm growth (1.5‐fold, p < .05), being 20 downexpressed and 31 overexpressed. The repressed proteins belonged to metabolism, biosynthesis and were outer membrane proteins (OMPs); and overexpressed were proteins involved in metabolism, transcription, translation, transport and proteins with unknown function. Also, of the seven enzymes that regulate the synthesis of butyrate, six of them were differentially expressed (overexpressed and downexpressed) when the bacteria were forming biofilms. The enzymatic activities of two of the enzymes in the butyrate pathway were analysed when the bacteria were growing in biofilms or in planktonic growth. All these results confirmed that this metabolic pathway is important in the formation of the biofilm of F. nucleatum and in its pathogenicity, both in the oral cavity and in other locations of the body.

Porphyromonas gingivalis, an oral microorganism residing in the subgingival biofilm, may exert diverse pathogenicity depending on the presence of specific virulence factors, but its gene expression has not been completely established. This investigation aims to compare the transcriptomic profile of this pathogen when growing within an in vitro multispecies biofilm or in a planktonic state. P. gingivalis ATCC 33277 was grown in anaerobiosis within multi-well culture plates at 37°C under two conditions: (a) planktonic samples (no hydroxyapatite discs) or (b) within a multispecies-biofilm containing Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans deposited on hydroxyapatite discs. Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) combined with Fluorescence In Situ Hybridization (FISH) were used to verify the formation of the biofilm and the presence of P. gingivalis. Total RNA was extracted from both the multispecies biofilm and planktonic samples, then purified and, with the use of a microarray, its differential gene expression was analyzed. A linear model was used for determining the differentially expressed genes using a filtering criterion of two-fold change (up or down) and a significance p-value of P. gingivalis. The microarray demonstrated that, when growing within the multispecies biofilm, 19.1% of P. gingivalis genes were significantly and differentially expressed (165 genes were up-regulated and 200 down-regulated), compared with planktonic growth. These genes were mainly involved in functions related to the oxidative stress, cell envelope, transposons and metabolism. The results of the microarray were confirmed by RT-qPCR. Significant transcriptional changes occurred in P. gingivalis when growing in a multispecies biofilm compared to planktonic state.

Objectives: To compare biofilm formation on whole dental titanium implants with different surface micro‐topography.Methods: A multispecies in vitro biofilm model consisting of initial (Streptococcus oralis and Actinomyces naeslundii), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late colonizers (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans) was grown for 96 hr on sterile titanium dental implants with either minimal (S_a: 0.5–1.0 mm) or moderate‐roughness titanium surfaces (S_a: 1.1–2.0 mm). The resulting biofilms were studied with Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscope. Concentrations (colony‐forming units per mL [CFU/ml]) of each bacterium were measured by quantitative Polymerase Chain Reaction (qPCR) and compared by Student t tests.Results: A biofilm, located mainly at the peak and lateral areas of the implant threads, was observed on both implant surfaces, with a greater biomass and a greater live/dead ratio in moderate‐ compared to minimal‐roughness surface implants. Statistically significant higher values of total bacteria (mean difference = 2.61 × 10⁷ CFU/ml; 95% confidence interval — CI [1.91 × 10⁶; 5.02 × 10⁷]; p = 0.036), F. Nucleatum (mean difference = 4.43 × 10⁶ CFU/ml; 95% CI [1.06 × 10⁶; 7.80 × 10⁶]; p = 0.013) and A. actinomycetemcomitans (mean difference = 2.55 × 10⁷ CFU/ml; 95% CI [1.07 × 10⁷; 4.04 × 10⁷]; p = 0.002), were found in the moderate‐ compared to minimal‐roughness surface dental implants.Conclusions: Implants with moderate‐roughness surfaces accumulated more bacterial biomass and significant higher number of pathogenic bacteria (F. nucleatum and A. actinomycetemcomitans), when compared to implants with minimal‐roughness surfaces, within a similar biofilm structure.