Probiotic and technological properties of Lactobacillus spp. strains from the human stomach in the search for potential candidates against gastric microbial dysbiosis

Unveiling the gastric microbiota: implications for gastric carcinogenesis, immune responses, and clinical prospects

High-throughput sequencing has ushered in a paradigm shift in gastric microbiota, breaking the stereotype that the stomach is hostile to microorganisms beyond H. pylori. Recent attention directed toward the composition and functionality of this 'community' has shed light on its potential relevance in cancer. The microbial composition in the stomach of health displays host specificity which changes throughout a person's lifespan and is subject to both external and internal factors. Distinctive alterations in gastric microbiome signature are discernible at different stages of gastric precancerous lesions and malignancy. The robust microbes that dominate in gastric malignant tissue are intricately implicated in gastric cancer susceptibility, carcinogenesis, and the modulation of immunosurveillance and immune escape. These revelations offer fresh avenues for utilizing gastric microbiota as predictive biomarkers in clinical settings. Furthermore, inter-individual microbiota variations partially account for differential responses to cancer immunotherapy. In this review, we summarize current literature on the influence of the gastric microbiota on gastric carcinogenesis, anti-tumor immunity and immunotherapy, providing insights into potential clinical applications.

First isolation of a probiotic candidate Enterococcus mundtii from Herniaria glabra L. and evaluation of its wound healing activity

In this study focused on probiotic properties of bacterium isolated from Herniaria glabra L. is a medicinal plant. The bacterium was isolated from H. glabra, and it was identified using the molecular method as Enterococcus mundtii AF-1 strain. Antibiotic sensitivity tests showed that AF-1 strain was sensitive to streptomycin, tobramycin, gentamicin, imipenem, erythromycin, and ciprofloxacin. The strain exhibited γ-haemolytic activity. These results show that the strain can be considered safe. The AF-1 strain showed inhibitory activity against some pathogens, including Bacillus subtilis, Klebsiella pneumoniae, and Yersinia pseudotuberculosis. Additionally, AF-1 strain exhibited high tolerance to low pH, pepsin, pancreatin, and bile salts. These properties showed that the strain may survival under the gastrointestinal conditions. The strain showed 40% DPPH free radical scavenging activity. The autoaggregation rate of the strain was 72.46% and the strain exhibited the high coaggregation rate (70.77% with Escherichia coli, and 63.78% with Listeria monocytogenesis). AF-1 strain showed 38.10% adhesion towards n-hexane, and 47.62% adhesion toward chloroform. It has been found to have moderate hydrophobicity. These results demonstrated the beneficial colonization ability of the strain in the gut. Furthermore, it was observed that living cells of AF-1 strain showed healing activity in the artificial wound area. Result of studies, it is seen that AF-1 strain might be excellent a probiotic candidate.

Effects of dietary chlorogenic acid on ileal intestinal morphology, barrier function, immune factors and gut microbiota of broilers under high stocking density stress

Aims: The purpose of this research was to assess the effect of chlorogenic acid (CGA) in the diet on ileac structure, barrier function, immunological state, and microbial profile of broiler chickens in a high stocking density (HD) environment. Methods: Four hundred and seventy-six male AA broiler chickens were randomly split into four groups, two with a normal stocking density (ND) of fourteen birds per m² and two with a high stocking density of twenty-two birds per m². Each of the treatments consisted of five replicates. One of the two ND and HD groups received the usual feed, while the other two were given at 1.5 g/kg CGA as part of their dietary regimen. Results: The ND CGA group showed a greater increase in villus height and villus height/crypt depth compared to the ND group at 35 and 42 days. The HD group experienced a greater elevation in villus height due to CGA supplementation than the HD group across days 28, 35, and 42. At day 42, the HD group saw a decline in OCLN and ZO-1 mRNA expression in the ileum, but CGA was able to restore them. The HD group experienced a greater rise in OCLN mRNA than the control HD group when supplemented with CGA. The expression of TNF-α, IL-1β, and IL-6 in the ileum was higher in the HD group, and CGA supplementation enhanced this effect. The HD group experienced a greater rise in IL-10 mRNA expression than the control group following the administration of CGA. The HD group showed reduced alpha diversity and an increase in detrimental microbes such as Turicibacter and Shigella in the gut compared to the ND group, while the HD CGA group saw a reduction in Turicibacter, Shigella, and other harmful microbes. These findings reveal that HD stress suppressed the growth of ileac villi, decreased the expression of tight-junction genes, amplified the expression of inflammatory genes, and disturbed the gut microbiota, ultimately leading to increased intestinal permeability. Conclusion: We conclude that when chickens are given dietary CGA, the disruption of the ileac barrier and increased oxidative damage and inflammation due to HD stress are reduced, which increases ileac integrity and the presence of beneficial intestinal bacteria.

Difference analysis of intestinal microbiota and metabolites in piglets of different breeds exposed to porcine epidemic diarrhea virus infection

The gut microbial composition of the Luchuan (LC) piglet, one of China’s native breeds, has rarely been studied, especially when compared to other breeds. This study developed a porcine epidemic diarrhea virus (PEDV) infection model in LC and Largewhite (LW) piglets, and analyzed the patterns and differences of intestinal microbial communities and metabolites in piglets of these two breeds after infection. The diarrhea score, survival time, and distribution of viral antigens in the intestine of piglets infected with PEDV differed among breeds, with the jejunal immunohistochemistry score of LW piglets being significantly higher than that of LC piglets (P < 0.001). The results of 16S rRNA sequencing showed differences in microbial diversity and community composition in the intestine of piglets with different breeds between PEDV infection piglets and the healthy controls. There were differences in the species and number of dominant phyla and dominant genera in the same intestinal segment. The relative abundance of Shigella in the jejunum of LC piglets after PEDV infection was significantly lower than that of LW piglets (P < 0.05). The key microorganisms differed in the microbiota were Streptococcus alactolyticus, Roseburia faecis, Lactobacillus iners, Streptococcus equi, and Lactobacillus mucosae (P < 0.05). The non-targeted metabolite analysis revealed that intestinal metabolites showed great differences among the different breeds related to infection. Spearman correlation analysis was conducted to examine any links between the microbiota and metabolites. The metabolites in the intestine of different breeds related to infection were mainly involved in arginine biosynthesis, synaptic vesicle cycle, nicotinic acid and nicotinamide metabolism and mTOR signaling pathway, with significantly positive or negative correlations (P < 0.05) between the various microorganisms. This study provides a theoretical foundation for investigating the application of core microorganisms in the gut of piglets of different breeds in the digestive tracts of those infected with PEDV, and helps to tackle the antimicrobial resistance problem further.

Microbiological quality analysis of inoculants based on Bradyrhizobium spp. and Azospirillum brasilense produced "on farm" reveals high contamination with non-target microorganisms

The use of inoculants carrying diazotrophic and other plant growth-promoting bacteria plays an essential role in the Brazilian agriculture, with a growing use of microorganism-based bioproducts. However, in the last few years, some farmers have multiplied microorganisms in the farm, known as "on farm" production, including inoculants of Bradyrhizobium spp. for soybean (Glycine max L. Merrill.) and Azospirillum brasilense for corn (Zea mays L.) or co-inoculation in soybean. The objective was to assess the microbiological quality of such inoculants concerning the target microorganisms and contaminants. In the laboratory, 18 samples taken in five states were serial diluted and spread on culture media for obtaining pure and morphologically distinct colonies of bacteria, totaling 85 isolates. Molecular analysis based on partial sequencing of the 16S rRNA gene revealed 25 genera of which 44% harbor species potentially pathogenic to humans; only one of the isolates was identified as Azospirillum brasilense, whereas no isolate was identified as Bradyrhizobium. Among 34 isolates belonging to genera harboring species potentially pathogenic to humans, 12 had no resistance to antibiotics, six presented intrinsic resistance, and 18 presented non-intrinsic resistance to at least one antibiotic. One of the samples analyzed with a shotgun-based metagenomics approach to check for the microbial diversity showed several genera of microorganisms, mainly Acetobacter (~ 32% of sequences) but not the target microorganism. The samples of inoculants produced on farm were highly contaminated with non-target microorganisms, some of them carrying multiple resistances to antibiotics.

The Combination of In Vitro Assessment of Stress Tolerance Ability, Autoaggregation, and Vitamin B-Producing Ability for New Probiotic Strain Introduction

The health benefits of probiotics are beyond doubt. The positive effects of lactobacilli and bifidobacteria on the function of many body systems have been repeatedly proven by various studies. To completely realize the potential of probiotic microorganisms, the strains should be tested by the greatest combination of characteristics that contribute to the wellness of the host. In this work, for the first time, a combined assessment of the probiotic properties and vitamin B-producing potential of various species and strains of bifidobacteria and lactobacilli was carried out. The presence of an additional advantage, such as vitamin-producing ability, can prevent vitamin deficiency both at the level of the consumption of fermented foods, when the enrichment will occur naturally on the spot, and during colonization by these intestinal strains, when synthesis will occur in vivo. To select potential probiotics, the stress tolerance ability of 16 lactic acid bacteria and bifidobacteria strains to low pH values, bile, and proteolytic enzymes, as well as their ability to autoaggregate, were studied under conditions of modeling the gastrointestinal tract in vitro. The ability of the strains to extracellularly accumulate water-soluble B vitamins was evaluated by capillary electrophoresis. Among the tested strains of bifidobacteria, B. adolescentis VKPM AC-1662 is of interest; it was characterized by the greatest stress tolerance ability and the ability to autoaggregate, in addition to the extracellular synthesis of riboflavin and pyridoxine. Among lactic acid bacteria, L. sakei VKPM B-8936 demonstrated the greatest tolerance to low pH, L. plantarum VKPM B–11007 to duodenal conditions, L. acidophilus VKPM B-2213 to pepsin, and L. salivarius VKPM B–2214 to pancreatin. The highest percentage of autoaggregation was observed in L. salivarius VKPM B-2214, which also accumulated the largest amount of pantothenic acid, but it was sensitive to stress conditions. The obtained results could be used to create new products enriched with probiotics and B vitamins.

Probiotics in the treatment of Helicobacter pylori infection: reality and perspective

Helicobacter pylori (H. pylori) infection is one of the most common in the world today, associated with the development of acute or chronic inflammatory diseases of the gastroduodenal tract. In order to eradicate the pathogen, various antibacterial therapy regimens have been proposed, based on the use of several chemotherapeutic drugs and a proton pump inhibitor (PPI). However, recent studies indicate a decrease in antibiotic effectiveness due to both the growth rate of H. pylori resistance and side effects, often due to the development of dysbiosis. One of the promising areas of investigation is the treatment with probiotic therapy of helicobacteriosis. The use of probiotics, in the context of H. pylori infection, has two main reasons. The first is related to the use of certain probiotics to reduce the frequency of undesirable gastrointestinal consequences during H. pylori eradication therapy. The second is associated with the antagonistic effect of individual probiotics on H. pylori and the potentiation of the eradication effect. The purpose of this review was to summarize the latest data on the use of probiotics to enhance H. pylori eradication and to restore the gastrointestinal microbiota. Many unresolved questions, about the choice of the specific composition of the probiotic cocktail, dosage, duration of therapy, mechanisms of the antimicrobial action of probiotics, as well as possible negative consequences of such therapy, remain.

[Characteristics of gastric microbiota in children with Helicobacter pylori infection family history]

OBJECTIVE

To explore the characteristics of gastric microbiota in children with and without (Helicobacter pylori, H. pylori) infection who had family history of H. pylori infection.

METHODS

Mucosal biopsy samples of the gastric corpus and gastric antrum were collected during the gastroscope. And the gastric mucosa flora's information of the two groups of children were obtained after sample DNA extraction, PCR amplification of the 16S ribosomal DNA (rDNA) V3-V4 region, high-throughput sequencing and data processing. All the samples with family history of H. pylori infection were divided into two groups, the H. pylori infection group (n=18) and the H. pylori non-infection group (n=24). Then the α-, β-diversity and bacteria abundance of the gastric microbiota were compared between the H. pylori infection and non-infection groups at different taxonomic levels. The differential microbiota was found out by LEfSe analysis, and then the function of microbiota predicted using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) method.

RESULTS

There was statistically significant difference in α-diversity (P < 0.05) between the two groups, indicating that the H. pylori non-infection group had higher microbial richness than the H. pylori infection group. Moreover, the β-diversity was significantly different as well (P < 0.05), which meant that the microbiota composition of the two groups was different. At the phyla level, Proteobacteria, Firmicutes, Bacteroides, Actinobacteria, and Fusobacteria were dominant in the two groups. At the genus level, Bacteroides, Prevotella, Streptococcus, and Neisseria, etc. were dominant in the H. pylori non-infected group. Meanwhile, Helicobacter and Haemophilus etc. were dominant in the H. pylori infected group. LEfSe analysis showed that the relative abundance of Bacteroides etc. at the genus level in the H. pylori non-infected group was significantly higher than that in the H. pylori infected group. Functional prediction showed that Bacteroides were positively correlated with amino acid and vitamin metabolism, mitogen-activated protein kinase (MAPK), mammalian target of rapamycin (mTOR) signaling pathway and ansamycin synthesis pathway.

CONCLUSION

The gastric microbiota between H. pylori positive and H. pylori negative in children with family history of H. pylori infection is significant different. Some gastric microbiota, such as Bacteroides, may have a potential relationship with H. pylori infection in children.

Interrelation: gastric microbiota - acid-dependent diseases, and more…

Introduction

The relationship between gastric microbiota and acid-dependent diseases is currently not fully studied. The study is based on a review of the literature to analyze and reflect the available data on the interaction of gastric microbiota and acid-dependent diseases, as well as brain-gut diseases.

Methods

The survey was performed by analyzing data from Medscape, PubMed, Elsevier. The articles analyzed are in English, Romanian, Russian, published in the last 10 years. Data on the composition (landscape) of the gastric microbiota and their influence on acid-dependent diseases and digestive diseases in general were reflected.

Results

The research reflected that in addition to Helicobacter pylori infection, the landscape of the gastric microbiota in the acid stomach (with low pH) is not sterile and includes other types such as: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Fusobacteria. At the same time, current methods document a bacterial load of 1010-1012 CFU/mL in the colon, which is much higher than in the stomach, where it reaches 102-104 CFU/mL. H. pylori influences the diversification of the non-H.pylori gastric microbiota; Decreased diversification increases the risk of carcinogenesis. The aspects of the role of H. pylori in functional dyspepsia, named after the Maastricht Consensus V - H. pylori dyspepsia, were also demonstrated. The taxonomic profiles (Philum-level, Genus-level) of the gastric microbiota require the study of the interrelationships with acid-dependent diseases, as well as the feedback.

Conclusions

The study shows that the stomach is not a sterile organ and in addition to H. pylori there are 5 other types of gastric microbiota, which are interrelated with acid-dependent diseases and digestive disorders and vice versa. This issue requires a comprehensive approach.

Role of Microbial Infection-Induced Inflammation in the Development of Gastrointestinal Cancers

There has been increasing evidence that a local inflammatory response stimulates tumor cells to acquire metastatic potential, and the concept of inflammatory oncotaxis has been spreading in recent years. However, the interaction between microbial inflammation and the development of gastrointestinal cancer is still unclear. This review summarizes the present knowledge on the role of microbial inflammation in the development of gastrointestinal cancers from the perspective of molecular biological findings. Chronic inflammation caused by bacterial infection is known to induce cancers as exemplified by Helicobacter pylori, which is associated with the development of gastric cancer via the activation of the TLR4 pathway by bacterial lipopolysaccharide followed by cancer growth through CagA-MET signaling. In addition, the development of inflammatory bowel diseases has been known to become a risk factor for colorectal cancers, where inflammation caused by certain bacterial infections plays a key role. It is also known that the cancer microenvironment is associated with cancer growth. Moreover, infectious complication after surgery for gastrointestinal cancers may promote tumor progression via the stimulation of pathogen-associated molecular patterns and various inflammatory mediators secreted by immunocytes. Further research on the link between microbial inflammation and cancer progression is needed to drive a paradigm shift in cancer treatment.

Potential probiotic and food protection role of wild yeasts isolated from pistachio fruits (Pistacia vera)

BACKGROUND

The biotechnological potential of yeasts from nuts such as pistachio, not only for health applications but also for industry use, has been scarcely studied. Interest in the probiotic capability of yeasts has increased in the past years as well as their utilization as food or feed preservatives. Their capabilities as biocontrol against problematic (spoilage or toxigenic) microorganisms or as antioxidants have been revalued. As a result, both abilities would be desirable to develop a new potential probiotic microorganism which could be added to food or feed to improve their properties.

RESULTS

Molecular techniques allowed the identification of a total of seven different species and 15 strains. A screening of the probiotic potential of these strains was carried out. It was found that 65% of the strains resisted the gastrointestinal conditions as well as presented a generation time of < 22 h. Additionally, some strains showed better kinetic parameters than Saccharomyces boulardii (positive control). Complementary tests were done to determine their auto-aggregation capacity, cell surface hydrophobicity, behaviour in a sequential simulated digestion, biofilm formation capability and carbon source assimilation. Finally, 67% and 13% of the studied yeasts showed biocontrol and antioxidant activities, respectively.

CONCLUSIONS

Diutina rugosa 14 followed by Diutina rugosa 8 were the best wild yeast from Pistacia vera as potential probiotic and in carbon source utilization. However, Hanseniaspora guilliermondii 6 and Aureobasidium proteae 5 could be used to improve food or feed product preservation because of their notable biocontrol and antioxidant capabilities. © 2020 Society of Chemical Industry.

A new probiotic candidate bacterium from human milk: Limosilactobacillus vaginalis MA-10

The probiotic and technological potentials of lactic acid bacteria originating from human milk are becoming a remarkable research area. In the present study, Limosilactobacillus vaginalis MA-10 isolated from human milk was investigated in vitro for its probiotic and technological aspects. According to the results obtained in the study, MA-10 strain exhibited non-haemolytic activity and various degrees of sensitivity to most of the tested antibiotics. The strain showed good resistance to the gastrointestinal system and maintained its viability under these conditions. Its antimicrobial activity against human or clinical bacterial and fungal microorganisms and fish bacteria was determined in the range of 2.38–11.22 mm. The MA-10 strain was able to assimilate cholesterol ranging from 31.42 to 82.30%. The strain showed 9.34% ferrous-ion chelating and 32% DPPH free radical scavenging activities. These initial results from the present study confirm that L. vaginalis MA-10 may be a new source with appropriated probiotic and technological traits for various industries, and further in vivo assays.Due to the limited number of studies on L. vaginalis strains originated from human breast milk in the literature, the data obtained in this study are thought to be important for revealing the basic probiotic properties of the strain.

Metataxonomic analysis of microbiota from Pakistani dromedary camelids milk and characterization of a newly isolated Lactobacillus fermentum strain with probiotic and bio-yogurt starter traits

This study was undertaken to investigate the starter and probiotic potential of lactic acid bacteria isolated from dromedarian camel's milk using both culture-dependent and -independent approaches and metataxonomic analysis. Strains of lactic acid bacteria recovered were examined in vitro for tolerance to gastric acidity, bile, and lysozyme. Bile salt hydrolysis, serum cholesterol-lowering, oxalate degradation, proteolytic activity, exopolysaccharide production, and cell surface characteristics necessary for colonizing intestinal mucosa were also evaluated. A single strain of the species, Lactobacillus fermentum named NPL280, was selected through multivariate analysis as it harbored potential probiotic advantages and fulfilled safety criteria. The strain assimilated cholesterol, degraded oxalate, produced exopolysaccharides, and proved to be a proficient alternate yogurt starter with good viability in stored bio-yogurt. A sensorial analysis of the prepared bio-yogurt was also found to be exemplary. We conclude that the indigenous L. fermentum strain NPL280 has the desired traits of a starter and adjunct probiotic culture for dairy products.

Technological properties of beneficial bacteria from the dairy environment and development of a fermented milk with the beneficial strain Lactobacillus casei MRUV6

In this research paper we describe the technological properties of beneficial lactic acid bacteria (LAB) obtained from a dairy production chain and the development of a fermented milk produced with Lactobacillus casei MRUV6. Fifteen LAB isolates (Lactobacillus sp., Pediococcus sp. and Weissela sp.) presented acidifying abilities (pH ranges from 0.73 to 2.11), were able to produce diacetyl (except by 5 isolates) and exopolysaccharides, and two were proteolytic. L. casei MRUV6 was selected for producing a fermented milk, stored up to 35 d at 4 and 10°C. Counts on MRS agar with added vancomycin (10 mg/l) and MRS agar with added bile salts (1.5% w/v) ranged from 9.7 to 9.9 log CFU/g, independently of the tested conditions, indicating stability and intestinal resistance of L. casei MRUV6, despite some significant differences (P < 0.05). The study demonstrated the technological potential of a potential probiotic candidate strain, L. casei MRUV6, to be used as a starter culture in the dairy industry.

The Exopolysaccharide of Lactobacillus fermentum UCO-979C Is Partially Involved in Its Immunomodulatory Effect and Its Ability to Improve the Resistance against Helicobacter pylori Infection

Lactobacillus fermentum UCO-979C (Lf979C) beneficially modulates the cytokine response of gastric epithelial cells and macrophages after Helicobacter pylori infection in vitro. Nevertheless, no in vivo studies were performed with this strain to confirm its beneficial immunomodulatory effects. This work evaluated whether Lf979C improves protection against H. pylori infection in mice by modulating the innate immune response. In addition, we evaluated whether its exopolysaccharide (EPS) was involved in its beneficial effects. Lf979C significantly reduced TNF-α, IL-8, and MCP-1 and augmented IFN-γ and IL-10 in the gastric mucosa of H. pylori-infected mice. The differential cytokine profile induced by Lf979C in H. pylori-infected mice correlated with an improved reduction in the pathogen gastric colonization and protection against inflammatory damage. The purified EPS of Lf979C reduced IL-8 and enhanced IL-10 levels in the gastric mucosa of infected mice, while no effect was observed for IFN-γ. This work demonstrates for the first time the in vivo ability of Lf979C to increase resistance against H. pylori infection by modulating the gastric innate immune response. In addition, we advanced knowledge of the mechanisms involved in the beneficial effects of Lf979C by demonstrating that its EPS is partially responsible for its immunomodulatory effect.

Helicobacter pylori Infection and Gastric Microbiota

Owing to its strong acid production, the stomach was known to be a bacteria-free organ for many years. On the other hand, the presence of Helicobacter pylori (H. pylori) and other acid-resistant microbiota that are to persist in the stomach challenged this. It is now recognized that the existence of H. pylori and non-H. pylori species have been linked to the improvement of gastric disease; despite this, there is little published data on the interaction of gastric bacterial flora and the resultant effect on gastric health. The stomach has a unique microbiota including five major phyla, such as Firmicutes, Proteobacteria, Actinobacteria, Fusobacteria and Bacteroidetes. These phyla are identified in both H. pylori-infected and uninfected persons. The resident gastric microflora may mediate the role of H. pylori in the gastric diseases. This article aims to review previous studies that examine the impact of H. pylori infection and the effect of resident gastric microbiota on gut health and disease conditions.

HOW TO CITE THIS ARTICLE

Ozbey G, Sproston E, Hanafiah A. Helicobacter pylori Infection and Gastric Microbiota. Euroasian J Hepato-Gastroenterol 2020;10(1):36-41.

Gastric microflora and gastric disease

Gastric environment has long been considered sterile, but the discovery of Helicobacter pylori (H. pylori) changed such concept in 1982. Over the past few decades, modern techniques have provided insight into microbial communities in the stomach and the interactions between communities, ranging from methods that rely on bacterial culture to the application of macrogenomics and high-throughput sequencing techniques. H. pylori is an important risk factor for gastric disease, but there may be other bacteria involved in the occurrence of gastric disease. This review summarizes the current progress in the understanding of the relationship between gastric microflora and gastric disease.

Characterization of the immunomodulatory and anti-Helicobacter pylori properties of the human gastric isolate Lactobacillus rhamnosus UCO-25A

The ability to form biofilms and the potential immunomodulatory properties of the human gastric isolate Lactobacillus rhamnosus UCO-25A were characterized in vitro. It was demonstrated that L. rhamnosus UCO-25A is able to form biofilms on abiotic and cell surfaces, and to modulate the inflammatory response triggered by Helicobacter pylori infection in gastric epithelial cells and THP-1 macrophages. L. rhamnosus UCO-25A exhibited a substantial anti-inflammatory effect in both cell lines and improved IL-10 levels produced by challenged macrophages. Additionally, UCO-25A protected AGS cells against H. pylori infection with a higher pathogen inhibition when a biofilm was formed. Given the importance of inflammation in H. pylori-mediated diseases, the differential modulation of the inflammatory response in the gastric mucosa by an autochthonous strain is an attractive alternative for improving H. pylori eradication and reducing the severity of the diseases that arise from the resulting chronic inflammation.

Probiotic Lactobacillus spp. act Against Helicobacter pylori-induced Inflammation

The bacterial species, Helicobacter pylori, is associated with several gastrointestinal diseases, and poses serious health threats owing to its resistance to antibiotics. Lactobacillus spp., on the other hand, possess probiotic activities that have beneficial effects in humans. However, the mechanisms by which Lactobacillus spp. harbor favorable functions and act against H. pylori infection remain to be explored. The aim of this study was to investigate the ability of bacterial strains, Lactobacillus rhamnosus and Lactobacillus acidophilus, termed GMNL-74 and GMNL-185, respectively, to inhibit H. pylori growth and inflammation. Our results showed that GMNL-74 and GMNL-185 possess potent antimicrobial activity against multidrug resistant (MDR)-H. pylori. In addition, an in vitro cell-based model revealed that the inhibition of H. pylori adhesion and invasion of gastric epithelial cells and interleukin-8 production were significantly decreased by treatment with both the Lactobacillus strains. In vivo studies demonstrated that colonization of H. pylori and induced inflammation in the mouse stomach were also alleviated by these Lactobacillus strains. Furthermore, the abundance of beneficial gut bacteria, including Bifidobacterium spp. and Akkermansia muciniphilia, were significantly increased in H. pylori-infected mice treated with GMNL-74 and GMNL-185. These results demonstrate that Lactobacillus spp. ameliorate H. pylori-induced inflammation and supports beneficial gut specific bacteria that act against H. pylori infection.

In Vitro Antimicrobial Activity and Downregulation of Virulence Gene Expression on Helicobacter pylori by Reuterin

Helicobacter pylori is an infectious agent commonly associated with gastrointestinal diseases. The use of probiotics to treat this infection has been documented, however, their potential antimicrobial metabolites have not yet been investigated. In the present study, the effect of reuterin produced by Lactobacillus reuteri on H. pylori growth and virulence gene expression was evaluated. It was observed that reuterin caused significant (P < 0.05) H. pylori growth inhibition at concentrations from 0.08 to 20.48 mM, with minimal inhibitory concentrations (MICs) of 20.48 mM for H. pylori ATCC700824 and 10.24 mM for H. pylori ATCC43504. In a reuterin bacterial killing assay, it was observed that half of the MIC value for H. pylori (ATCC700824) significantly (P < 0.01) reduced colony numbers from 5.65 ± 0.35 to 3.78 ± 0.35 Log₁₀ CFU/mL after 12 h of treatment and then increased them to 5.25 ± 0.23 Log₁₀ CFU/mL at 24 h; at its MIC value (20.48 mM), reuterin abrogated (P < 0.01) H. pylori (ATCC700824) growth after 20 h of culture. In addition, reuterin significantly (P < 0.01) reduced H. pylori (ATCC 43504) colony numbers from 5.65 ± 0.35 to 4.1 ± 0.12 Log10 CFU/mL from 12 to 24 h of treatment and abrogated its growth at its MIC value (10.24 mM), after 20 h of treatment. Reuterin did not alter normal human gastric Hs738.St/Int cell viability at the concentrations tested for H. pylori strains. Furthermore, 10 μM reuterin was shown to significantly (P < 0.01) reduce mRNA relative expression levels of H. pylori virulence genes vacA and flaA at 3 h post-treatment, whose effect was higher at 6 h post-treatment, as measured by RT-qPCR. The observed direct antimicrobial effect and the downregulation of expression of virulence genes on H. pylori by reuterin may contribute to the understanding of the mechanisms of action of probiotics against H. pylori.

Characterization of technological and probiotic properties of indigenous Lactobacillus spp. from south Brazil

In this study, we isolated Lactobacillus spp. from bovine raw milk and artisanal cheese from southern Brazil, and evaluated their technological and probiotic potential to select new isolates for producing healthy fermented dairy foods with differentiated tastes and flavours. We obtained 48 new lactobacilli isolates, which were isolated from raw milk (38) and cheese (10). These bacterial isolates were closely related with ten species: Lactobacillus paracasei (50% of the isolates), L. parabuchneri (15%), L. pentosus (13%), L. zeae (4%), L. plantarum (4%), L. otakiensis (4%), L. casei (4%), L. harbinensis (2%), L. diolivorans (2%), and L. rhamnosus (2%). Isolates CH112 and CH131 showed the greatest acidification potential, reducing the pH of milk to below 5.3 after incubation for 6 h at 32 °C. Considering proteolytic activity and diacetyl production, isolates ML88a, ML04, and ML12 showed the most promising results. Isolate ML12 showed 100% survival rate when inoculated in gastric juice at pH 2.5. The evaluation of antibacterial activity of the lactobacilli showed that the pathogens Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis, and Salmonella Typhimurium were strongly inhibited by the pure lactobacilli cultures. Five Lactobacillus isolates (ML01, ML04, ML12, ML88, and CH139) showed both technological and probiotic characteristics. Principal Component Analysis (PCA) was used to investigate correlations among technological and probiotic characteristics, and identified new promising lactobacilli isolates for exploring their characteristics. This study reveals the importance of selecting new microorganisms with potential applicability in the food industry for developing functional foods with differentiated aromas and flavours.

Food-Origin Lactic Acid Bacteria May Exhibit Probiotic Properties: Review

One of the most promising areas of development in the human nutritional field over the last two decades has been the use of probiotics and recognition of their role in human health and disease. Lactic acid-producing bacteria are the most commonly used probiotics in foods. It is well known that probiotics have a number of beneficial health effects in humans and animals. They play an important role in the protection of the host against harmful microorganisms and also strengthen the immune system. Some probiotics have also been found to improve feed digestibility and reduce metabolic disorders. They must be safe, acid and bile tolerant, and able to adhere and colonize the intestinal tract. The means by which probiotic bacteria elicit their health effects are not understood fully, but may include competitive exclusion of enteric pathogens, neutralization of dietary carcinogens, production of antimicrobial metabolites, and modulation of mucosal and systemic immune function. So far, lactic acid bacteria isolated only from the human gastrointestinal tract are recommended by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) for use as probiotics by humans. However, more and more studies suggest that strains considered to be probiotics could be isolated from fermented products of animal origin, as well as from non-dairy fermented products. Traditional fermented products are a rich source of microorganisms, some of which may exhibit probiotic properties. They conform to the FAO/WHO recommendation, with one exception; they have not been isolated from human gastrointestinal tract. In light of extensive new scientific evidence, should the possibility of changing the current FAO/WHO requirements for the definition of probiotic bacteria be considered?

Genomic Characterization and Probiotic Potency of Bacillus sp. DU-106, a Highly Effective Producer of L-Lactic Acid Isolated From Fermented Yogurt

Bacillus sp. DU-106, a newly isolated member of Bacillus cereus group, exhibits the predominant ability to produce L-lactic acid. The probiotic potency of test strain revealed its survivability at acidic pH, bile salts and viability in simulated gastric juice in vitro. The acute oral toxicity test indicated its no toxicity to laboratory mice in vivo. We further determined the complete genome of strain DU-106 to understand genetic basis as a potential probiotic. It has a circular chromosome and three plasmids for a total genome 5,758,208 bp in size with a G + C content of 35.10%. Genes associated with lactate synthesis were found in the DU-106 genome. We also annotated various stress-related, bile salt resistance, and adhesion-related domains in this strain, which likely provide support in exerting probiotic action by enabling adhesion to host epithelial cells and survival under gastrointestinal tract. Moreover, strain DU-106 genome lacks the virulence genes encodes cereulide synthetase, enterotoxin FM, and cytotoxin K. These phenotypic and genomic probiotic potencies facilitate its potential candidate as probiotic starter in food industry.

Gut microbiota derived metabolites in cardiovascular health and disease

Trillions of microbes inhabit the human gut, not only providing nutrients and energy to the host from the ingested food, but also producing metabolic bioactive signaling molecules to maintain health and elicit disease, such as cardiovascular disease (CVD). CVD is the leading cause of mortality worldwide. In this review, we presented gut microbiota derived metabolites involved in cardiovascular health and disease, including trimethylamine-N-oxide (TMAO), uremic toxins, short chain fatty acids (SCFAs), phytoestrogens, anthocyanins, bile acids and lipopolysaccharide. These gut microbiota derived metabolites play critical roles in maintaining a healthy cardiovascular function, and if dysregulated, potentially causally linked to CVD. A better understanding of the function and dynamics of gut microbiota derived metabolites holds great promise toward mechanistic predicative CVD biomarker discoveries and precise interventions.

Gastric microbiota: tracing the culprit

The gastric environment has been long time considered bacteria-free, but the discovery of Helicobacter pylori (H. pylori) in 1982 superseded this conception. Over the last decades new diagnostic methods have been developed, starting with culture-dependent and advancing to culture-independent ones. These modern techniques provide new insight into the composition and influence of this ecosystem on the entire gastrointestinal tract. H. pylori is no longer considered the only microorganism in the stomach, other non-H. pylori microbial species may populate the same environment and exercise their role. Current knowledge suggests possible links of these bacteria with gastroduodenal diseases, such as peptic ulcer and gastric cancer but most of them need further scientific evidence. This review summarizes current information on these complex interrelations between gastric microbial communities and host in health and disease.

Microbes and Viruses Are Bugging the Gut in Celiac Disease. Are They Friends or Foes?

The links between microorganisms/viruses and autoimmunity are complex and multidirectional. A huge number of studies demonstrated the triggering impact of microbes and viruses as the major environmental factors on the autoimmune and inflammatory diseases. However, growing evidences suggest that infectious agents can also play a protective role or even abrogate these processes. This protective crosstalk between microbes/viruses and us might represent a mutual beneficial equilibrium relationship between two cohabiting ecosystems. The protective pathways might involve post-translational modification of proteins, decreased intestinal permeability, Th1 to Th2 immune shift, induction of apoptosis, auto-aggressive cells relocation from the target organ, immunosuppressive extracellular vesicles and down regulation of auto-reactive cells by the microbial derived proteins. Our analysis demonstrates that the interaction of the microorganisms/viruses and celiac disease (CD) is always a set of multidirectional processes. A deeper inquiry into the CD interplay with Herpes viruses and Helicobacter pylori demonstrates that the role of these infections, suggested to be potential CD protectors, is not as controversial as for the other infectious agents. The outcome of these interactions might be due to a balance between these multidirectional processes.

The Gastric and Intestinal Microbiome: Role of Proton Pump Inhibitors

PURPOSE OF REVIEW

The discovery of Helicobacter pylori and other organisms colonizing the stomach and the intestines has shed some light on the importance of microbiome in maintaining overall health and developing pathological conditions when alterations in biodiversity are present. The gastric acidity plays a crucial role in filtering out bacteria and preventing development of enteric infections. In this article, we discuss the physiology of gastric acid secretion and bacterial contribution to the composition of gastric and intestinal barriers and review the current literature on the role of proton pump inhibitors (PPIs) in the microbial biodiversity of the gastrointestinal tract.

RECENT FINDINGS

Culture-independent techniques, such as 16S rRNA sequencing, have revolutionized our understanding of the microbial biodiversity in the gastrointestinal tract. Luminal and mucosa-associated microbial populations are not identical. Streptococcus is overrepresented in the biopsies of patients with antral gastritis and may also be responsible for the development of peptic ulcer disease. The use of PPIs favors relative streptococcal abundance irrespective of H. pylori status and may explain the persistence of dyspeptic symptoms in patients on PPI therapy. Increased risk of enteric infections has also been seen in patients taking PPIs. The overuse of PPIs leads to significant shift of the gastrointestinal microbiome towards a less healthy state. With the advent of PPIs, many studies have demonstrated the significant changes in the microbial composition of both gastric and intestinal microbiota. Although they are considered relatively safe over-the-counter medications, PPIs in many cases are over- and even inappropriately used. Future studies assessing the safety of PPIs and their role in the development of microbiome changes should be encouraged.

Bacterial Diversity of the Gastric Content of Preterm Infants during Their First Month of Life at the Hospital

Studies focused on the stomach microbiota are relatively scarce, and most of them are focused on the adult population. The aim of this work is to describe the bacterial communities inhabiting the gastric content (GC) of preterm neonates. For that purpose, GC samples were collected weekly from a total of 13 preterm neonates during their first month of life within their hospital stay. Samples were analyzed by using both culture-dependent and -independent techniques. The former allowed the isolation of bacteria belonging mainly to the genera Enterococcus, Staphylococcus, Streptococcus, Serratia, Klebsiella, and Escherichia. The cultured dominant species in the GC samples during all the hospitalization period were Enterococcus faecalis and Staphylococcus epidermidis. Multilocus sequence typing (MLST) analysis revealed the presence of high-risk clonal complexes associated with the hospital environment, which may colonize enteral feeding tubes. Similarly, the 16S rRNA sequencing showed that Streptococcus, Staphylococcus, Lactobacillus, Enterococcus, Corynebacterium, and Propionibacterium were the dominant genera present at 75% of the gastric samples. However, the genera Serratia, Klebsiella, and Streptococcus were the most abundant. Own mother's milk (OMM) and donor milk (DM) were collected after their pass through the external feeding tubes to assess their bacterial content. OMM and DM had a similar bacterial pattern to GC. Based on these data, the GC of preterm neonates is dominated by Proteobacteria and Firmicutes and harbors high-risk bacterial clones, which may colonize enteral feeding tubes, and therefore the feeds that pass through them.

The Esophageal and Gastric Microbiome in Health and Disease

The esophagus and stomach are host to their own population of bacteria, which differs in health and disease. Helicobacter pylori uniquely colonizes only gastric mucosa, but an increasing number of bacteria is now isolated from the gastric juice and gastric mucosa, including Lactobacillus. The presence of H pylori alters populations of other gastric bacteria with a marked reduction in diversity. Alterations in intragastric acidity may be the cause or the consequence of changes in the microbial populations of the stomach. Esophageal inflammation is associated with an altered microbiota in gastroesophageal reflux disease, Barrett's esophagus, eosinophilic esophagitis, and cancer.

Genome shuffling of Lactobacillus plantarum C88 improves adhesion

Genome shuffling is an important method for rapid improvement in microbial strains for desired phenotypes. In this study, ultraviolet irradiation and nitrosoguanidine were used as mutagens to enhance the adhesion of the wild-type Lactobacillus plantarum C88. Four strains with better property were screened after mutagenesis to develop a library of parent strains for three rounds of genome shuffling. Fusants F3-1, F3-2, F3-3, and F3-4 were screened as the improved strains. The in vivo and in vitro tests results indicated that the population after three rounds of genome shuffling exhibited improved adhesive property. Random Amplified Polymorphic DNA results showed significant differences between the parent strain and recombinant strains at DNA level. These results suggest that the adhesive property of L. plantarum C88 can be significantly improved by genome shuffling. Improvement in the adhesive property of bacterial cells by genome shuffling enhances the colonization of probiotic strains which further benefits to exist probiotic function.

Microbiological, biochemical and organoleptic properties of fermented-probiotic drink produced from camel milk

The microbiological and biochemical changes occurred during the fermentation of camel milk inoculated by three selected bacterial starter, were investigated as well as the sensory evaluation of the product. Milk samples were collected from camel herds of southeastern of Iran. Chr. Hansen ABT-10 starter including Lactobacillus acidophillus, Biphidobacterum biphidum and Sterptococcus thermophilus in ratio of 0.50 g per 100 mL of camel milk was added. This fermented product was examined at the 0, 3^rd, 6^th and 9^th days for microbiological, biochemical and sensory evaluations. The results showed the number of starter bacteria was maintained at least 10⁶ CFU mL^-1 during nine test days. It was shown that it could be used as fermented-probiotic drink. The product did not show any microbial contamination. The acidity and protein amount of produced drink showed a significant (p < 0.05) increase in different test days. Fat, solids-not-fat and ash amount of the product showed significant differences at the ninths' test day compared to the zero test day (p < 0.05). Organoleptic properties of product including flavor, color, odor, consistency, mouth feel and overall acceptance were significantly improved (p < 0.05). Therefore, the produced fermented-probiotic drink, in addition to keep maintenance and increased nutritional quantity value, was accepted by consumers in terms of organoleptic properties and it could be used as a healthy and functional drink.

Lactoferrin Adsorbed onto Biomimetic Hydroxyapatite Nanocrystals Controlling - In Vivo - the Helicobacter pylori Infection

Background

The resistance of Helicobacter pylori to the antibiotic therapy poses the problem to discover new therapeutic approaches. Recently it has been stated that antibacterial, immunomodulatory, and antioxidant properties of lactoferrin are increased when this protein is surface-linked to biomimetic hydroxyapatite nanocrystals.

Objective

Based on these knowledge, the aim of the study was to investigate the efficacy of lactoferrin delivered by biomimetic hydroxyapatite nanoparticles with cell free supernatant from probiotic Lactobacillus paracasei as an alternative therapy against Helicobacter pylori infection.

Methods

Antibacterial and antinflammatory properties, humoral antibody induction, histopathological analysis and absence of side effects were evaluated in both in vitro and in vivo studies.

Results

The tests carried out have been demonstrated better performance of lactoferrin delivered by biomimetic hydroxyapatite nanoparticles combined with cell free supernatant from probiotic Lactobacillus paracasei compared to both lactoferrin and probiotic alone or pooled.

Conclusion

These findings indicate the effectiveness and safety of our proposed therapy as alternative treatment for Helicobacter pylori infection.

Different gastric microbiota compositions in two human populations with high and low gastric cancer risk in Colombia

Inhabitants of Túquerres in the Colombian Andes have a 25-fold higher risk of gastric cancer than inhabitants of the coastal town Tumaco, despite similar H. pylori prevalences. The gastric microbiota was recently shown in animal models to accelerate the development of H. pylori-induced precancerous lesions. 20 individuals from each town, matched for age and sex, were selected, and gastric microbiota analyses were performed by deep sequencing of amplified 16S rDNA. In parallel, analyses of H. pylori status, carriage of the cag pathogenicity island and assignment of H. pylori to phylogeographic groups were performed to test for correlations between H. pylori strain properties and microbiota composition. The gastric microbiota composition was highly variable between individuals, but showed a significant correlation with the town of origin. Multiple OTUs were detected exclusively in either Tumaco or Túquerres. Two operational taxonomic units (OTUs), Leptotrichia wadei and a Veillonella sp., were significantly more abundant in Túquerres, and 16 OTUs, including a Staphylococcus sp. were significantly more abundant in Tumaco. There was no significant correlation of H. pylori phylogeographic population or carriage of the cagPAI with microbiota composition. From these data, testable hypotheses can be generated and examined in suitable animal models and prospective clinical trials.

Pathogenesis of Helicobacter pylori Infection

Three decades have passed since Warren and Marshall described the successful isolation and culture of Helicobacter pylori, the Gram-negative bacterium that colonizes the stomach of half the human population worldwide. Although it is documented that H. pylori infection is implicated in a range of disorders of the upper gastrointestinal tract, as well as associated organs, many aspects relating to host colonization, successful persistence, and the pathophysiological mechanisms of this bacteria still remain controversial and are constantly being explored. Unceasing efforts to decipher the pathophysiology of H. pylori infection have illuminated the crucially important contribution of multifarious bacterial factors for H. pylori pathogenesis, in particular the cag pathogenicity island (PAI), the effector protein CagA, and the vacuolating cytotoxin VacA. In addition, recent studies have provided insight into the importance of the gastrointestinal microbiota on the cumulative pathophysiology associated with H. pylori infection. This review focuses on the key findings of publications related to the pathogenesis of H. pylori infection published during the last year, with an emphasis on factors affecting colonization efficiency, cagPAI, CagA, VacA, and gastrointestinal microbiota.

Gastric Microbiota

After the discovery of Helicobacter pylori in 1983, the stomach was no longer considered a sterile environment. In 2015, evolving data shows that H. pylori is not the only inhabitant of the gastric mucosa. Using culture-independent methods of analysis, a non-H. pylori microbial community has been recently observed in the human stomach, the so-called human gastric microbiota, along with H. pylori itself. Increasing evidence supports the hypothesis that although H. pylori may be the most relevant, it is not the only local bacterial culprit leading to gastric diseases. Further studies are warranted to offer a better picture of the role and functions of gastric microbiota and to identify the best therapeutic modulators of gut microbiota for the management of gastric diseases.