Gut Microbiota Modulation by Selenium and Zinc Enrichment Postbiotic on Dysbiosis Associated with Hypertension.

BACKGROUND: Targeting gut dysbiosis to treat chronic diseases or to alleviate the symptoms is a new direction for medical adjuvant therapies. Recently, postbiotics have received considerable attention as they are non-viable probiotic preparations that confer various health benefits to the host without the safety problems associated with using live microbial cells. OBJECTIVE: The aim of the study is to obtain selenium (Se) and zinc (Zn) enriched Saccharomyces boulardii postbiotic biomass and to analyze its modulation effect because these minerals play an important role in reducing gut dysbiosis linked to cardiovascular (CV) diseases. METHOD: The effect of the S. boulardii and Se/Zn enriched yeast postbiotics on CV microbial fingerprint was studied in vitro using the gastrointestinal system (GIS 1) and analyzed by microbiological, chemical, and qPCR methods. RESULT: There was a 2.2 log CFU/mL increase in the total bacterial load after SeZn postbiotic treatment and in the qPCR counts of Firmicutes phyla for both treatments. Beneficial taxa, Bifidobacterium spp. and Lactobacillus spp., as well as Bacteroides spp. were up to 1.5 log higher after mineral- enriched postbiotic application, while the acetic acid level increased. CONCLUSION: These preliminary studies highlight the therapeutic potential of using Se/Zn enriched yeast postbiotics as adjuvants for clinical treatments of CV diseases.

Improving the Efficiency of Viability-qPCR with Lactic Acid Enhancer for the Selective Detection of Live Pathogens in Foods.

Pathogenic Escherichia coli are the most prevalent foodborne bacteria, and their accurate detection in food samples is critical for ensuring food safety. Therefore, a quick technique named viability-qPCR (v-qPCR), which is based on the ability of a selective dye, such as propidium monoazide (PMA), to differentiate between alive and dead cells, has been developed. Despite diverse, successful applications, v-qPCR is impaired by some practical limitations, including the ability of PMA to penetrate the outer membrane of dead Gram-negative bacteria. The objective of this study is to evaluate the ability of lactic acid (LA) to improve PMA penetration and, thus, the efficiency of v-qPCR in detecting the live fraction of pathogens. The pre-treatment of E. coli ATCC 8739 cells with 10 mM LA greatly increased PMA penetration into dead cells compared to conventional PMA-qPCR assay, avoiding false positive results. The limit of detection when using LA-PMA qPCR is 1% viable cells in a mixture of dead and alive cells. The optimized LA-PMA qPCR method was reliably able to detect log 2 CFU/mL culturable E. coli in milk spiked with viable and non-viable bacteria. Lactic acid is cheap, has low toxicity, and can be used to improve the efficiency of the v-qPCR assay, which is economically interesting for larger-scale pathogen detection applications intended for food matrices.

Gut Microbiota Modulators Based on Polyphenols Extracted from Winery By-Products and Their Applications in the Nutraceutical Industry.

Vine-growing for the production of wine is one of the oldest and most important agricultural activities worldwide, but the winemaking process leads to vast amounts of waste. Viticulture and vinification by-products have many bioactive molecules, including polyphenols, prebiotic fibers, organic acids, and minerals. While research on the specific human health effects of grapevine residues (pomace, seeds, barks, stalks, canes, and leaves) is still ongoing, the available data suggest the potential to positively modulate the normal and dysbiotic gut microbiota (GM) using polyphenol-rich extracts obtained from winery by-products. This review provides an updated summary of the in vitro and in vivo evidence in animal models and humans concerning the ability of polyphenol-rich winery residue to be used as a GM modulator that supports their nutraceutical applications as a functional ingredient. Additionally, this review aims to enhance interest in viticulture waste (grapevine stems and leaves), as the levels of polyphenols are similar to those found in red grapes or seeds. However, more research is still needed to obtain innovative products. The valorization of winery residues is not only environmentally friendly; it can also be economically beneficial, creating added-value nutraceuticals that modulate microbiota and a new revenue stream for wine producers.

The Modulation Effect of a Fermented Bee Pollen Postbiotic on Cardiovascular Microbiota and Therapeutic Perspectives.

Hypertension is a frequent comorbidity in patients with heart failure; therefore, blood pressure management for these patients is widely recommended in medical guidelines. Bee pollen and postbiotics that contain inactivated probiotic cells and their metabolites have emerged as promising bioactive compounds sources, and their potential role in mitigating cardiovascular (CV) risks is currently being unveiled. Therefore, this preliminary study aimed to investigate the impact of a lactic-fermented bee pollen postbiotic (FBPP) on the CV microbiota via in vitro tests. A new isolated Lactobacillus spp. strain from the digestive tract of bees was used to ferment pollen, obtaining liquid and dried atomized caps postbiotics. The modulating effects on a CV microbiota that corresponds to the pathophysiology of hypertension were investigated using microbiological methods and qPCR and correlated with the metabolic profile. Both liquid and dried FBPPs increased the number of the beneficial Lactobacillus spp. and Bifidobacterium spp. bacteria by up to 2 log/mL, while the opportunistic pathogen E. coli, which contributes to CV pathogenesis, decreased by 3 log/mL. The short-chain fatty acid (SCFA) profile revealed a significant increase in lactic (6.386 ± 0.106 g/L) and acetic (4.284 ± 0.017 g/L) acids, both with known antihypertensive effects, and the presence of isovaleric acid, which promotes a healthy gut microbiota. Understanding the impact of the FBPP on gut microbiota could lead to innovative strategies for promoting heart health and preventing cardiovascular diseases.

Mineral-Enriched Postbiotics: A New Perspective for Microbial Therapy to Prevent and Treat Gut Dysbiosis.

Postbiotics are non-viable probiotic preparations that confer a health benefit on the host. In the last years, scientific literature has proved that postbiotics have health-promoting features and technological advantages compared to probiotics, augmenting their full potential application in the food and pharmaceutical industries. The current work comprehensively summarizes the benefits and potential applications of postbiotics and essential mineral-enriched biomass and proposes a new strategy for microbial therapy-mineral-enriched postbiotics. We hypothesize and critically review the relationship between micronutrients (calcium, magnesium, iron, zinc, selenium) and postbiotics with gut microbiota, which has been barely explored yet, and how the new approach could be involved in the gut microbiome modulation to prevent and treat gut dysbiosis. Additionally, the bioactive molecules and minerals from postbiotics could influence the host mineral status, directly or through gut microbiota, which increases the mineral bioavailability. The review increases our understanding of the health improvements of mineral-enriched postbiotics, including antioxidant functions, highlighting their perspective on microbial therapy to prevent and threaten gut-related diseases.

Therapeutic Properties of Edible Mushrooms and Herbal Teas in Gut Microbiota Modulation.

Edible mushrooms are functional foods and valuable but less exploited sources of biologically active compounds. Herbal teas are a range of products widely used due to the therapeutic properties that have been demonstrated by traditional medicine and a supplement in conventional therapies. Their interaction with the human microbiota is an aspect that must be researched, the therapeutic properties depending on the interaction with the microbiota and the consequent fermentative activity. Modulation processes result from the activity of, for example, phenolic acids, which are a major component and which have already demonstrated activity in combating oxidative stress. The aim of this mini-review is to highlight the essential aspects of modulating the microbiota using edible mushrooms and herbal teas. Although the phenolic pattern is different for edible mushrooms and herbal teas, certain non-phenolic compounds (polysaccharides and/or caffeine) are important in alleviating chronic diseases. These specific functional compounds have modulatory properties against oxidative stress, demonstrating health-beneficial effects in vitro and/or In vivo. Moreover, recent advances in improving human health via gut microbiota are presented. Plant-derived miRNAs from mushrooms and herbal teas were highlighted as a potential strategy for new therapeutic effects.

Induction of viable but nonculturable Escherichia coli O157:H7 in the phyllosphere of lettuce: a food safety risk factor.

Escherichia coli O157:H7 continues to be an important human pathogen and has been increasingly linked to food-borne illness associated with fresh produce, particularly leafy greens. The aim of this work was to investigate the fate of E. coli O157:H7 on the phyllosphere of lettuce under low temperature and to evaluate the potential hazard of viable but nonculturable (VBNC) cells induced under such stressful conditions. First, we studied the survival of six bacterial strains following prolonged storage in water at low temperature (4°C) and selected two strains with different nonculturable responses for the construction of E. coli O157:H7 Tn7gfp transformants in order to quantitatively assess the occurrence of human pathogens on the plant surface. Under a suboptimal growth temperature (16°C), both E. coli O157:H7 strains maintained culturability on lettuce leaves, but under more stressful conditions (8°C), the bacterial populations evolved toward the VBNC state. The strain-dependent nonculturable response was more evident in the experiments with different inoculum doses (10(9) and 10(6) E. coli O157:H7 bacteria per g of leaf) when strain BRMSID 188 lost culturability after 15 days and strain ATCC 43895 lost culturability within 7 days, regardless of the inoculum dose. However, the number of cells entering the VBNC state in high-cell-density inoculum (approximately 55%) was lower than in low-cell-density inoculum (approximately 70%). We recorded the presence of verotoxin for 3 days in samples that contained a VBNC population of 4 to 5 log(10) cells but did not detect culturable cells. These findings indicate that E. coli O157:H7 VBNC cells are induced on lettuce plants, and this may have implications regarding food safety.

Nonculturable response of animal enteropathogens in the agricultural environment and implications for food safety.

Concerns about animal enteropathogen contamination of fresh horticultural products have,increased worldwide and are mainly due to the ability of bacteria to survive under stress conditions in the agricultural environment and during raw-vegetable processing. This review challenges the idea that the viable but nonculturable phenomenon that has been proven to occur in plant-associated environments contributes to human pathogen survival and might be correlated with foodborne infection. Factors associated with the nonculturable response of bacteria in the field and during postharvest processing and distribution are discussed, specifically for the most common animal enteropathogens linked with the consumption of raw products: Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Shigella spp. The accurate detection of live bacterial populations is essential for pathogen screening in food and environmental safety control and in epidemiological analysis and may have to be considered for identification of critical control points at the time of food inspection.

Behavior of Escherichia coli O157:H7 in leafy vegetables.

Leafy vegetables, including lettuce and spinach, have been implicated in several outbreaks of foodborne disease caused by Escherichia coli O157:H7, a pathogen of increasing public health significance because of the severity of the gastrointestinal illness and long-term, chronic sequelae that can result from infection. A definitive association between the consumption of leafy vegetables and human disease provides implicit evidence of transfer from animal sources to field crops and retail commodities, including minimally processed or fresh-cut products. Understanding the behavior of E. coli O157:H7 in leafy vegetables during production, after harvest, in storage, during processing, and in packaged fresh-cut products is essential for the development of effective control measures. To this end, previous research on the fate of the species at each step in the production of market-ready leafy vegetables is reviewed in this study. Several critical gaps in knowledge are identified, notably uncertainty about the location of contaminating cells on or in plant tissues, behavior in packaged products stored at low temperatures, and the influence of environmental stresses on growth and infectivity.