Quality assurance criteria for probiotic bacteria

In vitro controlled release of the probiotic strain Bacillus licheniformis PPL2016 microencapsulated: Simulating the digestive system by age class and sex in the blue swimming crab Callinectes arcuatus

This work aims to encapsulate Bacillus licheniformis PPL2016 (12 × 106 CFU/mL), a marine probiotic characterized at a biochemical and molecular level, in sodium alginate (2%) microparticles and to evaluate its controlled and directed release in a simulated digestive system (DS) of the swimming crab Callinectes arcuatus, considering the following age classes and sexes: Adult Female, Juvenile Female, Adult Male, and Juvenile. The encapsulation process was carried out using the ionic gelation technique. The microcapsules were characterized physiochemically by their size, morphology, number of encapsulated bacteria after the encapsulation process, as well as bacterial survival after 45 days of storage (4 °C). The in vitro release and survival studies of bacteria inside the organs that make up the DS of C. arcuatus were carried out using a protocol developed in our laboratory by applying extracts of dissected organs from the DS (stomach, hepatopancreas and intestine) of the swimming crab. A χ2 test (α = 0.05) was performed at linearization (Log10) of the percentages of the controlled releases of microencapsulated B. licheniformis PPL2016 at different times (0 h, 4 h, 8 h, 12 h), corresponding to the extracts of the organs which simulated the digestive system of C. arcuatus. After biochemical characterization B. licheniformis PPL2016 was considered probiotic bacteria. Microparticles with an average size of 602 to 639 µm were obtained after using the ionic gelation method. Bacterial survival and encapsulation efficacy showed high cell viability and performance above 77.94%. Stability studies showed that storage at a temperature of 4 °C, kept almost 100% of viable bacteria for 15 days; however, cell viability decreased to a survival of 90% after 30 days of storage at this temperature. Regardless of reduced cell viability after 30 days, there are enough viable bacterial cells. Release and survival studies showed that alginate particles had a protective effect on bacteria, these results suggest that microparticles can be produced by a low-cost method. In juvenile males, the percentage of release of probiotic bacteria was greater in TIV in the enzyme extract of the intestine (12 h) with 95 ± 0.45%. Juvenile males had the lowest in vitro release at the stomach stage (0 h) and thus marks the significance for their low release of microcapsules at the beginning of the in vitro release (χ2 = 6.7509; χ2Calculated Pool = 13.5188; χ2Calculated Critical (0.05, 21) = 11.5919; p < 0.05), with the highest significance in the intestine (12 h) (χ2 = 1.2602; χ2Calculated Pool = 13.5188; χ2Calculated Critical (0.05, 21) = 11.5919; p < 0.05). Significant differences in vitro bacterial release were recorded for age classes and sexes of C. arcuatus.

Functional diversity of AI-2/LuxS system in lactic acid bacteria: Impacts on biofilm formation and environmental resilience

A key component of microbial communication, autoinducer-2 (AI-2) signaling, affects several physiological processes, including environmental adaptation and biofilm formation in lactic acid bacteria (LAB). The multifarious contribution of AI-2, synthesized by LuxS, in improving biofilms and tolerance to hostile conditions in LAB has been investigated in this review. The evolutionary conservation and diversity of AI-2 are shown by a phylogenetic analysis of luxS gene among several LAB species. Furthermore, AI-2 signaling in LAB improves resistance to unfavorable environmental factors, including pH fluctuations, temperature extremes, and antimicrobial agents. Lactic acid bacteria could set off defenses against harmful impacts from environmental stresses.

A comprehensive approach, based on the use of Caenorhabditis elegans, mouse, and human models, elucidates the impact of Lactiplantibacillus plantarum TWK10 on exercise performance and longevity

The functionality of probiotics is highly influenced by culture and processing conditions, making batch stability validation through human or mouse trials impractical. Here, we employed a comprehensive approach using Caenorhabditis elegans, mouse and human models to elucidate the beneficial effects of Lactiplantibacillus plantarum TWK10 (TWK10). In C. elegans, TWK10 administration significantly prolonged lifespan by 26.1 ± 11.9 % (p < 0.05), enhanced locomotion (p < 0.01) and muscle mass (p < 0.001), elevated glycogen storage (p < 0.05), and reduced lipid accumulation (p < 0.001), outperforming Lacticaseibacillus rhamnosus GG and L. plantarum type strain ATCC 14917T. We also confirmed the equivalence of laboratory-prepared and mass-produced TWK10 in ergogenic efficacy using C. elegans assay. In mice, oral administration of mass-produced TWK10 significantly enhanced exercise performance and glycogen storage in muscle and liver in a dose-dependent manner. In a clinical study involving healthy male adults, significant improvements in grip strength (1.1-fold, p < 0.01) and exhaustion time (1.27-fold, p < 0.01), and significant reductions in circulating lactate and ammonia levels were observed in the TWK10 group (1 × 1010 colony-forming unit/day) compared to the control group. Both humans and mice receiving mass-produced TWK10 showed improved body composition with increased muscle mass and reduced fat mass. In conclusion, TWK10 demonstrates superior longevous and ergogenic effects in C. elegans compared to reference strains. The consistent ergogenic efficacy of mass-produced TWK10 across C. elegans, mice, and humans, highlights the utility of C. elegans as a reliable model for probiotic research and industrial application.

Development of Chitosan-Polyacrylic Acid Complex Systems for Enhanced Oral Delivery of Lactobacillus Gasseri and Bifidobacterium Bifidum Probiotics

Introduction

The beneficial effects of probiotics are encountered by their low viability in gastrointestinal conditions and their insufficient stability during manufacturing, throughut the gastrointestinal transit, and storage. Therefore, novel systems are highly required to improve probiotics delivery.

Methods

In this study, Lactobacillus gasseri (L), Bifidobacterium bifidum (B), and a combination of L+B were encapsulated in chitosan (CS)-polyacrylic acid (PAA) complex systems (CS-PAA). The CS-PAA systems were analysed on basis of morphology, size, and zeta potential. The loaded CS-PAA systems were evaluated for their morphology, particle size, zetapotential, vaiability in both simulated gastroic and intestinal fluids, and stability at 4°C storage temparature. Moreover, the antibiofilm activity of the probiotics-loaded systems were evaluated againt Campylobacter jejuni, Pseudomonas aeruginosa and Escherichia coli.

Results

Probiotic strains were successfully incorporated into the porous structures of the CS-PAA systems, either individually or in combination. The Loaded L, B, and L+B showed higher particle size than the unloaded particles and excellent viability in simulated gastric and intestinal fluids, where the free probiotic species were undetected. Additionally the loaded probiotic exhibited an anti-biofilm effect at 0.5 mg/mL concentration level.

Conclusion

The CS-PAA complexes demonstrate a promising mechanism for the effective delivery of incorporated probiotics. The probiotics exhibited high viability and maintain stability under physiological conditions, and showed a remarkable anti-biofilm activity. These characteristics suggest that CS-PAA could serve as an alternative system for probiotics, enhancing gut microbiota health and offering a robust protection against microbial pathogens.

Influences of Bacillus pumilus SA388 as an environmentally friendly antibiotic alternative on growth performance, blood biochemistry, immunology, cecal microbiota, and meat quality in broiler chickens

The widespread use of antibiotics causes the development of antibiotic-resistant bacterial strains, which have a severe impact on poultry productivity and human health. As a result, research is continuing to develop safe natural antibiotic alternatives. In the current study, Bacillus pumilus SA388 was isolated from the chicken feces and confirmed to be a probiotic. The selected strain was tested for its antimutagenic and antioxidant capabilities before being employed as a probiotic food supplement and antibiotic alternative. The effect of B. pumilus SA388 impact on broiler chickens' growth performance, gut microbiome, blood biochemical markers, immunological response, and meat quality was also studied. B. pumilus SA388 showed significant bactericidal activity against Streptococcus pyogenes, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Klebsiella pneumonia. A total of 200 chickens were used in the present study, divided equally among four experimental groups (ten birds per group with 5 replicates): group 1 (control, G1) received a basal diet without B. pumilus SA388, group 2 (G2) received a basal diet supplemented with 0.4 mg/kg of B. pumilus SA388, group 3 (G3) received a basal diet supplemented with 0.8 mg/kg of B. pumilus SA388, and group 4 (G4) received a basal diet supplemented with 1.6 mg/kg of B. pumilus SA388. Over 35 d, the B. pumilus SA388-supplemented groups outperformed the G1 in terms of body weight gain, performance index, and feed conversion ratio, with a preference for the G4 treatment. The levels of alanine aminotransferase (ALT), aspartate transaminase (AST), low-density lipoprotein (LDL), and total cholesterol decreased significantly (P < 0.05) with increasing B. pumilus SA388 dosages compared to the control G1 group. Dietary supplementation of B. pumilus SA388 at 1.6 mg/kg (G4) significantly (P < 0.05) resulted in improved lipid profile, immunological response, thyroid function, and gut microbiota compared to the control group (G1). Compared to the broilers in the control treatment (G1), the addition of B. pumilus SA388 to broilers in G4 significantly (P < 0.05) enhanced juiciness, tenderness, aroma, and taste. Adding B. pumilus SA388 to chicken feed at different doses significantly (P < 0.05) decreased average feed intake while increasing economic and relative efficiency measures. In conclusion, B. pumilus SA388 has been proven to be an effective antibiotic and nutritional supplement.

Probiotics and Prebiotics for the Treatment of Irritable Bowel Syndrome-A Narrative Review

Background/Objectives: Gastrointestinal functional disorders (GFDs), including irritable bowel syndrome (IBS), are imbalances in the gut-brain axis characterized by persistence of symptoms in the abdominal area. Probiotics are live microorganisms that provide benefits to the health of their hosts when administered in adequate amounts, while prebiotics are a substrate that is selectively used by host microorganisms. This narrative review aimed to evaluate the effectiveness of prebiotics and probiotics mostly in irritable bowel syndrome, particularly on issues such as the interaction between these products and the gut microbiota, the duration of supplementation and long-term effects, the definition of ideal dosages, and the regulation and quality control of these products. Methods: A bibliographic search was carried out in indexed databases and articles published within 10 years before the beginning of the study and publications in English language, which investigated the specific theme of the study were considered. Papers dealing with topics not covered by the research questions, or presenting errors related with the wrong population or the wrong methods, as well as experimental studies and case reviews were excluded. Fifty-five articles were selected, initially in isolation by the authors and, afterward, under consensus. Results: It was possible to observe the effectiveness mainly of probiotics, in improving specific symptoms of the respective disorder; however, the available data remain unclear due to limitations concerning samples and methods of the studies evaluated. Conclusions: Despite evidence suggestive of therapeutic efficacy, additional multicenter randomized controlled trials (RCTs) with better defined protocols are still necessary to fill in the gaps in this subject, define measures to ensure the safe administration of these products, and confirm their therapeutic potential.

Exploring the Potential Probiotic Properties of Bifidobacterium breve DSM 32583-A Novel Strain Isolated from Human Milk

Human milk is the best nutrition for infants, providing optimal support for the developing immune system and gut microbiota. Hence, it has been used as source for probiotic strain isolation, including members of the genus Bifidobacterium, in an effort to provide beneficial effects to infants who cannot be exclusively breastfed. However, not all supplemented bifidobacteria can effectively colonise the infant gut, nor confer health benefits to the individual infant host; therefore, new isolates are needed to develop a range of dietary products for this specific age group. Here, we investigated the beneficial potential of Bifidobacterium breve DSM 32583 isolated from human milk. We show that in vitro B. breve DSM 32583 exhibited several characteristics considered fundamental for beneficial bacteria, including survival in conditions simulating those present in the digestive tract, adherence to human epithelial cell lines, and inhibition of growth of potentially pathogenic microorganisms. Its antibiotic resistance patterns were comparable to those of known beneficial bifidobacterial strains, and its genome did not contain plasmids nor virulence-associated genes. These results suggest that B. breve DSM 32583 is a potential probiotic candidate.

Gut Microbiota and Probiotics in Perioperative Management: A Narrative Review

The human gut is the abode of several complex and diverse microbes. It is a fact that the human brain is interconnected with the spinal cord and sense organs; however, there is also a possibility of a connection between the brain and the gut microbiome. The human gut can be altered in various ways, the principal method being the intake of prebiotics, probiotics and synbiotics. Can this alteration in the gut microbiome be clinically utilised in the perioperative period? We conducted a literature search related to this topic using databases and search engines (Medical Literature Analysis and Retrieval System Online {MEDLINE}, Embase, Scopus, PubMed and Google Scholar). The search revealed some preclinical and clinical studies in animals and humans that demonstrate the alteration of the gut microbiome with the use of anxiolysis, probiotics/prebiotics and other perioperative factors including opioids, anaesthetics and perioperative stress. The significant effects of this alteration have been seen on preoperative anxiety and postoperative delirium/cognitive dysfunction/pain. These effects are described in this narrative review, which opens up newer vistas for high-quality research related to the gut microbiome, gut-brain axis, the related signaling pathways and their clinical application in the perioperative period.

Identification and characterization of four Bacillus species from the intestine of hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂), their antagonistic role on common pathogenic bacteria, and effects on intestinal health

As an alternative to the criticized antibiotics, probiotics have been adopted for their eco-friendly nature and ability to enhance host growth and immunity. Nevertheless, reports suggest ineffectiveness in commercially available probiotics since most are from non-fish sources; thus, this study was envisaged to isolate and characterize new Bacillus spp. from the gut of hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂) which could serve as potential probiotics. The isolation and characterization were performed based on their morphological and biochemical properties, and 16S rRNA sequencing homology analysis. A subsequent 30-day in vivo biosafety feeding trial was conducted to ascertain isolates' non-pathogenicity, as well as their effects on fish growth, and intestinal mucosal microvilli via scanning electron microscopy (SEM) analysis. Four Bacillus spp. strains, namely, B. velezensis strain PGSAK01 (accession number OQ726606), B. stercoris strain PGSAK05 (accession number OQ726607), B. velezensis strain PGSAK17 (accession number OQ726601), and B. subtilis strain PGSAK19 (accession number OQ726605), were identified and characterized in the current study. The strains showed promising probiotic properties such higher adhesion capability, higher thermotolerance, displaying higher survivability to 0.5 % bile, lower pH tolerance, γ-haemolytic activity, and multispecies characteristics. Among the 24 antibiotics tested, while all isolates showed susceptibility to 21, the PGSAK01 strain showed resistance to furazolidone antibiotics. None of the isolates showed possession of i) virulence factor genes encoding enterotoxigenic (hblA, hblC, hblD, nheA, nheB, and entFM) and emetic (cereulide synthetase gene, ces) genes, and ii) streptomycin resistance gene (vat c), ampicillin-resistant genes (mecA and bla), and vancomycin-resistant gene (van B). Nevertheless, the PGSAK01 and PGSAK17 strains showed possession of tek K, cat, and ant(4')-Ia (adenylyltransferase) (except the PGSAK01) resistant genes. All isolates displayed better antimicrobial effects against pathogenic bacteria Streptococcus agalactiae, S. iniae, Vibrio harveyi, and V. alginolyticus. The in vivo biosafety trial involved hybrid grouper fish being grouped into five (average weight 32 ± 0.94 g), namely, the group fed the basal diet void of isolate's supplementation (control), and the remaining four groups fed the basal diet with 1 × 108 CFU/g diet of individual strain PGSAK01, PGSAK05, PGSAK17, and PGSAK19 supplementation. At the end of the study, a significantly higher WGR, K (except the PGSAK01 group), VSI; lysozyme (except PGSAK01 group), total antioxidant activity, alkaline phosphatase, superoxide dismutase enzyme activities; highly dense intestinal mucosal villi (based on the scanning electron microscopy analysis); and significantly lower malondialdehyde levels were witnessed in the isolated treated groups compared to the control, supporting the results obtained in the auto-aggregation and cell-surface hydrophobicity test. This work's results have provided thought-provoking targets; thus, studies involving extensive genome sequencing and functional annotation analysis will be explored to offer unfathomable insights into their mechanisms of action and potential health benefits, further establishing the four Bacillus strains' (PGSAK01, PGSAK05, PGSAK17, and PGSAK19) potential role in probiotic fields and functional foods.

Genomic Sequence of Streptococcus salivarius MDI13 and Latilactobacillus sakei MEI5: Two Promising Probiotic Strains Isolated from European Hakes (Merluccius merluccius, L.)

Frequently, diseases in aquaculture have been fought indiscriminately with the use of antibiotics, which has led to the development and dissemination of (multiple) antibiotic resistances in bacteria. Consequently, it is necessary to look for alternative and complementary approaches to chemotheraphy that are safe for humans, animals, and the environment, such as the use of probiotics in fish farming. The objective of this work was the Whole-Genome Sequencing (WGS) and bioinformatic and functional analyses of S. salivarius MDI13 and L. sakei MEI5, two LAB strains isolated from the gut of commercial European hakes (M. merluccius, L.) caught in the Northeast Atlantic Ocean. The WGS and bioinformatic and functional analyses confirmed the lack of transferable antibiotic resistance genes, the lack of virulence and pathogenicity issues, and their potentially probiotic characteristics. Specifically, genes involved in adhesion and aggregation, vitamin biosynthesis, and amino acid metabolism were detected in both strains. In addition, genes related to lactic acid production, active metabolism, and/or adaptation to stress and adverse conditions in the host gastrointestinal tract were detected in L. sakei MEI5. Moreover, a gene cluster encoding three bacteriocins (SlvV, BlpK, and BlpE) was identified in the genome of S. salivarius MDI13. The in vitro-synthesized bacteriocin BlpK showed antimicrobial activity against the ichthyopathogens Lc. garvieae and S. parauberis. Altogether, our results suggest that S. salivarius MDI13 and L. sakei MEI5 have a strong potential as probiotics to prevent fish diseases in aquaculture as an appropriate alternative/complementary strategy to the use of antibiotics.

Restriction of growth and biofilm formation of ESKAPE pathogens by caprine gut-derived probiotic bacteria

The accelerated rise in antimicrobial resistance (AMR) poses a significant global health risk, necessitating the exploration of alternative strategies to combat pathogenic infections. Biofilm-related infections that are unresponsive to standard antibiotics often require the use of higher-order antimicrobials with toxic side effects and the potential to disrupt the microbiome. Probiotic therapy, with its diverse benefits and inherent safety, is emerging as a promising approach to prevent and treat various infections, and as an alternative to antibiotic therapy. In this study, we isolated novel probiotic bacteria from the gut of domestic goats (Capra hircus) and evaluated their antimicrobial and anti-biofilm activities against the 'ESKAPE' group of pathogens. We performed comprehensive microbiological, biochemical, and molecular characterizations, including analysis of the 16S-rRNA gene V1-V3 region and the 16S-23S ISR region, on 20 caprine gut-derived lactic acid bacteria (LAB). Among these, six selected Lactobacillus isolates demonstrated substantial biofilm formation under anaerobic conditions and exhibited robust cell surface hydrophobicity and autoaggregation, and epithelial cell adhesion properties highlighting their superior enteric colonization capability. Notably, these Lactobacillus isolates exhibited broad-spectrum growth inhibitory and anti-biofilm properties against 'ESKAPE' pathogens. Additionally, the Lactobacillus isolates were susceptible to antibiotics listed by the European Food Safety Authority (EFSA) within the prescribed Minimum Inhibitory Concentration limits, suggesting their safety as feed additives. The remarkable probiotic characteristics exhibited by the caprine gut-derived Lactobacillus isolates in this study strongly endorse their potential as compelling alternatives to antibiotics and direct-fed microbial (DFM) feed supplements in the livestock industry, addressing the escalating need for antibiotic-free animal products.

Identification and biological characteristics of Enterococcus casseliflavus TN-47 isolated from Monochamus alternatus

With the widespread use of antibiotics, the incidence of antibiotic resistance in microorganisms has increased. Monochamus alternatus is a trunk borer of pine trees. This study aimed to investigate the in vitro antimicrobial and biological characteristics of Enterococcus casseliflavus TN-47 (PP411196), isolated from the gastrointestinal tract of M. alternatus in Jilin Province, PR China. Among 13 isolates obtained from the insects, five were preliminarily screened for antimicrobial activity. E. casseliflavus TN-47, which exhibited the strongest antimicrobial activity, was identified. E. casseliflavus TN-47 possessed antimicrobial activity against Staphylococcus aureus USA300 and Salmonella enterica serovar Pullorum ATCC 19945. Furthermore, E. casseliflavus TN-47 was sensitive to tetracyclines, penicillins (ampicillin, carbenicillin, and piperacillin), quinolones and nitrofuran antibiotics, and resistant to certain beta-lactam antibiotics (oxacillin, cefradine and cephalexin), macrolide antibiotics, sulfonamides and aminoglycosides. E. casseliflavus TN-47 could tolerate low pH and pepsin-rich conditions in the stomach and grow in the presence of bile acids. E. casseliflavus TN-47 retained its strong auto-aggregating ability and hydrophobicity. This strain did not exhibit any haemolytic activity. These results indicate that E. casseliflavus TN-47 has potential as a probiotic. This study provides a theoretical foundation for the future applications of E. casseliflavus TN-47 and its secondary metabolites in animal nutrition and feed.

Up-regulation of sortase-dependent pili in Bifidobacterium longum BBMN68 in response to bile stress enhances its adhesion to HT-29 cells

Adhesion to gastrointestinal tract is crucial for bifidobacteria to exert their probiotic effects. Our previous work found that bile salts significantly enhance the adhesion ability of Bifidobacterium longum BBMN68 to HT-29 cells. In this study, trypsin-shaving and LC-MS/MS-based surface proteomics were employed to identify surface proteins involved in bile stress response. Among the 829 differentially expressed proteins, 56 up-regulated proteins with a fold change >1.5 were subjected to further analysis. Notably, the minor pilin subunit FimB was 4.98-fold up-regulated in response to bile stress. In silico analysis and RT-PCR confirmed that gene fimB, fimA and srtC were co-transcribed and contributed to the biosynthesis of sortase-dependent pili Pil1. Moreover, scanning electron microscopy and immunogold electron microscopy assays showed increased abundance and length of Pil1 on BBMN68 under bile stress. As the major pilin subunit FimA serves as adhesion component of Pil1, an inhibition assay using anti-FimA antibodies further confirmed the critical role of Pil1 in mediating the adhesion of BBMN68 to HT-29 cells under bile stress. Our findings suggest that the up-regulation of Pil1 in response to bile stress enhances the adhesion of BBMN68 to intestinal epithelial cells, highlighting a novel mechanism of gut persistence in B. longum strains.

Evaluation of penicillin-resistance and probiotic traits in Lactobacillus plantarum during laboratory evolution

The aim of this study was to obtain the Lactobacillus plantarum ATCC14917 with high-level resistance to penicillin and evaluate their probiotic traits using laboratory evolution assay and whole-genome sequencing. In penicillin environment, the minimum inhibitory concentration (MIC) of L. plantarum to penicillin increased from 1 μg/mL to 16 μg/mL and remained stable after the removal of antibiotic pressure, suggesting that the resistance acquisition to penicillin was an irreversible process. Subsequently, change of probiotic characteristics was further evaluated, and the results showed that the acid tolerance, bile tolerance and adhesion ability were significantly declined in the highly resistant strains. Whole-genome sequencing indicated that genes encoding hypothetical protein, LPXTG-motif cell wall anchor domain protein and acetyltransferase were detected in highly resistant L. plantarum, and these genes were still present after the following subculture in the absence of penicillin, suggesting that these three mutants might be the main reason for the development of penicillin resistance. The homology-based analysis of surrounding DNA regions of mutant genes was further performed and indicated that no resistant genes were located on mobile elements in evolved L. plantarum strains, signifying that the spread of antibiotic resistance genes in the gut would not occur for these mutant genes. This study provided a basis for the combined use of highly resistant L. plantarum and penicillin in the treatment of pathogen induced gut diseases.

Bifidobacterium and the intestinal mucus layer

Bifidobacterium species are integral members of the human gut microbiota and these microbes have significant interactions with the intestinal mucus layer. This review delves into Bifidobacterium-mucus dynamics, shedding light on the multifaceted nature of this relationship. We cover conserved features of Bifidobacterium-mucus interactions, such as mucus adhesion and positive regulation of goblet cell and mucus production, as well as species and strain-specific attributes of mucus degradation. For each interface, we explore the molecular mechanisms underlying these interactions and their potential implications for human health. Notably, we emphasize the ability of Bifidobacterium species to positively influence the mucus layer, shedding light on its potential as a mucin-builder and a therapeutic agent for diseases associated with disrupted mucus barriers. By elucidating the complex interplay between Bifidobacterium and intestinal mucus, we aim to contribute to a deeper understanding of the gut microbiota-host interface and pave the way for novel therapeutic strategies.

Selective Antagonism of Lactiplantibacillus plantarum and Pediococcus acidilactici against Vibrio and Aeromonas in the Bacterial Community of Artemia nauplii

Empiric probiotics are commonly consumed by healthy individuals as a means of disease prevention, pathogen control, etc. However, controversy has existed for a long time regarding the safety and benefits of probiotics. Here, two candidate probiotics, Lactiplantibacillus plantarum and Pediococcus acidilactici, which are antagonistic to Vibrio and Aeromonas species in vitro, were tested on Artemia under in vivo conditions. In the bacterial community of Artemia nauplii, L. plantarum reduced the abundance of the genera Vibrio and Aeromonas and P. acidilactici significantly increased the abundance of Vibrio species in a positive dosage-dependent manner, while higher and lower dosages of P. acidilactici increased and decreased the abundance of the genus Aeromonas, respectively. Based on the liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) analyses of the metabolite of L. plantarum and P. acidilactici, pyruvic acid was used in an in vitro test to explain such selective antagonism; the results showed that pyruvic acid was conducive or suppressive to V. parahaemolyticus and beneficial to A. hydrophila. Collectively, the results of this study demonstrate the selective antagonism of probiotics on the bacterial community composition of aquatic organisms and the associated pathogens. IMPORTANCE Over the last decade, the common preventive method for controlling potential pathogens in aquaculture has been the use of probiotics. However, the mechanisms of probiotics are complicated and mostly undefined. At present, less attention has been paid to the potential risks of probiotic use in aquaculture. Here, we investigated the effects of two candidate probiotics, L. plantarum and P. acidilactici, on the bacterial community of Artemia nauplii and the in vitro interactions between these two candidate probiotics and two pathogens, Vibrio and Aeromonas species. The results demonstrated the selective antagonism of probiotics on the bacterial community composition of an aquatic organism and its associated pathogens. This research contributes to providing a basis and reference for the long-term rational use of probiotics and to reducing the inappropriate use of probiotics in aquaculture.

High-protein compound yogurt with quinoa improved clinical features and metabolism of high-fat diet-induced nonalcoholic fatty liver disease in mice

Gut microbiota dysbiosis plays a crucial role in the occurrence and progression of nonalcoholic fatty liver disease (NAFLD), which may be influenced by nutritional supplementation. Quinoa, a type of pseudocereal, has gained prominence due to its high nutritional value and diverse applications. This study aimed to determine whether yogurt containing quinoa can ameliorate NAFLD and alleviate metabolic disorders by protecting against the divergence of gut microbiota. Our findings suggested that quinoa yogurt could significantly reduce the body weight gain and fat tissue weight of high-fat diet (HFD)-fed obese mice. In addition, quinoa yogurt significantly reduced liver steatosis and enhanced glucose homeostasis and insulin sensitivity. Additional research indicates that quinoa yogurt can reduce the levels of proinflammatory cytokines (i.e., tumor necrosis factor α, IL-1β, and IL-6) and inhibit endotoxemia and systemic inflammation. The characteristics of the gut microbiota were then determined by analyzing 16S rRNA. In addition, we discovered that the gut microbiota was disturbed by HFD consumption. Particularly, intestinal probiotics and beneficial intestinal secretions were increased, leading to the expression of glucagon-like peptide-1 in the colon, contributing to NAFLD. Furthermore, endotoxemia and systemic inflammation in HFD-fed mice were restored to the level of control mice when they were fed yogurt and quinoa. Therefore, yogurt containing quinoa can effectively alleviate NAFLD symptoms and may exert its effects via microbiome-gut-liver axis mechanisms. According to some research, the role of the enteric-liver axis may also influence metabolic disorders to reduce the development of NAFLD.

Enterococcus isolated from poultry intestine for potential probiotic use

Background and Aim

To develop species-specific probiotics for poultry, it is ideal to obtain these probiotic microorganisms directly from the intestinal tract of broiler and egg-laying chicks in production environments to ensure adaptation to actual conditions. This study aimed to isolate lactic acid bacteria (LAB) from the intestinal tract of broiler and egg-laying chicks to determine their probiotic potential.

Materials and Methods

Twenty-five Ross-308 broilers and 25 Isa Brown egg-laying chicks were raised until days 42 and 120, respectively; they were housed in an individual poultry building. Lactic acid bacteria were isolated and identified from the small intestine mucus of broiler and layer chicks and then evaluated based on resistance to acidic pH levels, bile salt concentration, and antagonistic activity against wild strains of Escherichia coli and Salmonella spp. selected strains with probiotic potential were identified by polymerase chain reaction and confirmed by rDNA sequencing.

Results

One hundred and fifty Gram-positive isolates were obtained; 28% (42) were catalase and oxidase negative and biochemical identification was made by crystal system: 76.2% (32) Enterococcus spp., 16.6% (7) Lactococcus spp., and 7.2% (3) Streptococcus spp.; and evaluated for hemolysin production; tolerance to low pH and bile salts, and antagonistic potential were carried out. Molecular characterization yielded 56% (24) Enterococcus faecium, and 44% (18) Enterococcus faecalis. About 81% (34) of strains were without vancomycin resistance genes criterion.

Conclusion

This study isolated and characterized 36 strains of LAB with probiotic qualities, from the intestines of broiler and egg-laying chicks, selecting E. faecium, Enterococcus avium, and Enterococcus casseliflavus, Lactococcus garviae as promising strains for further in vitro and in vivo research.

Probiotics Alleviate Chemotherapy-Associated Intestinal Mucosal Injury via the TLR4-NFκB Signaling Pathway

Introduction

Temozolomide (TMZ) induces intestinal mucosa injury that cannot be fully counteracted by supportive treatment. Probiotics regulate gut microbial composition and the host immune system and may alleviate this side effect. We aimed to investigate the potential and mechanism of Lactobacillus rhamnosus GG (LGG) in relieving intestinal mucosal injury induced by TMZ.

Methods

Glioblastoma mice were divided into four groups: CON (control), LGG (10⁹ CFU/mL, treated for 7 days), TMZ (50 mg/kg·d, treated for 5 days), LGG+TMZ (LGG for 7 days and TMZ subsequently for 5 days). Body weight, food intake, and fecal pH were recorded. Intestinal tissue samples were collected 1 day after the end of TMZ treatment. Degree of damage to intestine, expression of IL1β, IL6, TNFα, and IL10 in jejunum were determined. Levels of tight-junction proteins (ZO1, occludin), TLR4, IKKβ, IκBα, and P65 with their phosphorylation in jejunum were measured.

Results

Decreases in body weight, food intake, spleen index in the TMZ group were mitigated in the LGG+TMZ group, and the degree of intestinal shortening and damage to jejunum villus were also alleviated. The expression of tight-junction proteins in the LGG+TMZ group was significantly greater than that in the TMZ group. IκBα in intestinal tissue significantly decreased in the TMZ group, phos-IKKβ and phos-P65 increased compared to the CON group, and LGG reversed such changes in IκBα and phos-P65 in the LGG+TMZ group. Intestinal inflammatory cytokines were significantly increased in the TMZ group, but lower in the LGG+TMZ group. Moreover, expression of TLR4 in LGG group was significantly lower than that in the CON group. LGG inhibited the rise of TLR4 after TMZ in the LGG+TMZ group compared to the TMZ group.

Conclusion

LGG inhibits the activation of the TLR4-NFκB pathway and alleviates intestinal mucosal inflammation induced by TMZ, thereby protect the jejunum villi and mucosal physical barrier.

Akkermansia muciniphila in neuropsychiatric disorders: friend or foe?

An accumulating body of evidence suggests that the bacterium Akkermansia muciniphila exhibits positive systemic effects on host health, mainly by improving immunological and metabolic functions, and it is therefore regarded as a promising potential probiotic. Recent clinical and preclinical studies have shown that A. muciniphila plays a vital role in a variety of neuropsychiatric disorders by influencing the host brain through the microbiota-gut-brain axis (MGBA). Numerous studies observed that A. muciniphila and its metabolic substances can effectively improve the symptoms of neuropsychiatric disorders by restoring the gut microbiota, reestablishing the integrity of the gut mucosal barrier, regulating host immunity, and modulating gut and neuroinflammation. However, A. muciniphila was also reported to participate in the development of neuropsychiatric disorders by aggravating inflammation and influencing mucus production. Therefore, the exact mechanism of action of A. muciniphila remains much controversial. This review summarizes the proposed roles and mechanisms of A. muciniphila in various neurological and psychiatric disorders such as depression, anxiety, Parkinson's disease, Alzheimer's disease, multiple sclerosis, strokes, and autism spectrum disorders, and provides insights into the potential therapeutic application of A. muciniphila for the treatment of these conditions.

Commercial probiotic products in public health: current status and potential limitations

Consumption of commercial probiotics for health improvement and disease treatment has increased in popularity among the public in recent years. The local shops and pharmacies are brimming with various probiotic products such as probiotic food, dietary supplement and pharmaceuticals that herald a range of health benefits, from nutraceutical benefits to pharmaceutical effects. However, although the probiotic market is expanding rapidly, there is increasing evidence challenging it. Emerging insights from microbiome research and public health demonstrate several potential limitations of the natural properties, regulatory frameworks, and market consequences of commercial probiotics. In this review, we highlight the potential safety and performance issues of the natural properties of commercial probiotics, from the genetic level to trait characteristics and probiotic properties and further to the probiotic-host interaction. Besides, the diverse regulatory frameworks and confusing probiotic guidelines worldwide have led to product consequences such as pathogenic contamination, overstated claims, inaccurate labeling and counterfeit trademarks for probiotic products. Here, we propose a plethora of available methods and strategies related to strain selection and modification, safety and efficacy assessment, and some recommendations for regulatory agencies to address these limitations to guarantee sustainability and progress in the probiotic industry and improve long-term public health and development.

Bacterial composition of a competitive exclusion product and its correlation with product efficacy at reducing Salmonella in poultry

The mature intestinal microbiome is a formidable barrier to pathogen colonization. Day-old chicks seeded with cecal contents of adult hens are resistant to colonization with Salmonella, the basis of competitive exclusion. Competitive exclusion products can include individual microbes but are commonly undefined intestinal communities taken from adult animals and in commercial production is amplified in fermentator and sold commercially in freeze dried lots. While superior to single and multiple species probiotics, reducing Salmonella colonization by multiple logs, undefined products have limited acceptance because of their uncharacterized status. In this study, the bacterial composition of the master stock, preproduction seed stocks and commercial lots of a poultry competitive exclusion product, was defined by 16S rRNA sequence analysis, targeting the 16S rRNA variable region (V1-V3). The samples contained a diversity of genera (22-52 distinct genera) however, the commercial lots displayed less diversity compared to the seeds and the master stock. Community composition varied between seeds and the master stock and was not a good predictor of potency, in terms of log₁₀ reduction in Salmonella abundance. While there was significant correlation in composition between seeds and their commercial lots, this too was a not a good predictor of potency. There was linear correlation between unclassified Actinobacteria, Peptococcus, and unclassified Erysipelotrichaceae, and Salmonella abundance (r ² > .75) for commercial seeds. However, upon review of the literature, these three genera were not consistently observed across studies or between trials that examined the correlation between intestinal community composition and Salmonella prevalence or abundance.

Intracellular glycogen accumulation by human gut commensals as a niche adaptation trait

The human gut microbiota is a key contributor to host metabolism and physiology, thereby impacting in various ways on host health. This complex microbial community has developed many metabolic strategies to colonize, persist and survive in the gastrointestinal environment. In this regard, intracellular glycogen accumulation has been associated with important physiological functions in several bacterial species, including gut commensals. However, the role of glycogen storage in shaping the composition and functionality of the gut microbiota offers a novel perspective in gut microbiome research. Here, we review what is known about the enzymatic machinery and regulation of glycogen metabolism in selected enteric bacteria, while we also discuss its potential impact on colonization and adaptation to the gastrointestinal tract. Furthermore, we survey the presence of such glycogen biosynthesis pathways in gut metagenomic data to highlight the relevance of this metabolic trait in enhancing survival in the highly competitive and dynamic gut ecosystem.

In Vitro Characterisation of Potential Probiotic Bacteria Isolated from a Naturally Fermented Carrot and Ginger Brine

Unhealthy dietary patterns have been associated with an increase in mortality rate as well as the high occurrence of nontransmissible chronic degenerative diseases. Subsequently, the development of new functional foods has been proposed to reduce the incidence of nontransmissible chronic degenerative diseases. Probiotics represent a group of functional foods, defined as live microbial feeds, which provide the host with intestinal health benefits. The present study focused on the identification and characterisation of the probiotic potential of lactic acid bacteria isolated from a fermented carrot and ginger brine. Sixteen isolates were identified as Leuconostoc mesenteroides subsp. mesenteroides species, following preliminary screening based on 16S rDNA gene sequencing, and were further characterised for probiotic candidature. The probiotic properties tested included resistance towards gastrointestinal conditions (bile, acid, lysozyme tolerance), cell surface hydrophobicity, antioxidant activity, and antagonistic activity against intestinal pathogens. In general, all the isolated Leuconostoc mesenteroides subsp. mesenteroides strains exhibited high acid, bile, and lysozyme tolerance. They also showed strong antibacterial activity against common intestinal pathogens, i.e., Staphylococcus aureus and Escherichia coli, as well as antioxidant activity such as hydroxyl radical-scavenging ability and hydrogen peroxide resistance. Overall, Leuconostoc mesenteroides subsp. mesenteroides possesses a great potential as a beneficial strain for functional food.

Aldrich C. A Review of Application Strategies and Efficacy of Probiotics in Pet Food

In companion animal nutrition, probiotics (direct-fed microbials) are marketed as functional ingredients that add value to pet foods due to the impact they have on gastrointestinal and immune health of dogs and cats. The nature of the beneficial effect each probiotic strain exerts depends on its metabolic properties and perhaps most importantly, the arrival of a sufficient number of viable cells to the large bowel of the host. Pet food manufacturing processes are designed to improve food safety and prolong shelf-life, which is counterproductive to the survival of direct-fed microbials. Therefore, a prerequisite for the effective formulation of pet foods with probiotics is an understanding of the conditions each beneficial bacterial strain needs to survive. The aims of this chapter are: (1) To summarize the inherent characteristics of probiotic strains used in commercial pet foods, and (2) To review recently published literature on the applications of probiotics to pet foods and their associated challenges to viability.

Haematological Features of White Rats (Rattus norvegicus) Infected with S. pyogenes and Administered with Probiotics (Yogurt)

This study aimed to study the inhibition activity of lactic acid bacteria probiotics deriving from Acehnese fermented Etawa goat's milk (yogurt) against Streptococcus pyogenes bacterial infection in rats (Rattus norvegicus). Haematological analysis of the rats' blood was performed on the following parameters: platelets, leukocytes, lymphocytes, neutrophils, and monocytes, where the data were further processed using ANOVA and Duncan's test with a confidence level of 95% (0.05). The results revealed that administering yogurt containing probiotics could reduce infections in the throats of rats caused by S. pyogenes. Based on the haematology examination, the probiotic yogurt could maintain the number of platelets, leukocytes, lymphocytes, neutrophils, and monocytes. Statistical significance was obtained when the infected rats were administered with a ±1.00 mL/day dose for seven days of treatment (p < 0.05).

Inhibitory effect of probiotic Bacillus spp. isolated from the digestive tract of Rhynchocypris Lagowskii on the adhesion of common pathogenic bacteria in the intestinal model

Diseases of fish caused by pathogenic bacteria are an important constraint on aquaculture production. Antibiotics have been widely used to control infectious diseases, but this has led to the emergence of drug-resistant bacteria and affected human health. In this context, probiotics are used as an alternative to antibiotics for the prevention and control of diseases in aquaculture. The aim of this study was to obtain probiotic candidate strains of Bacillus spp. from the gut of Rhynchocypris Lagowskii. Strains were screened by enzyme-producing ability, antagonism assay and antibiotic susceptibility. The safety of the strains to host fish has also been established. The isolated Bacillus licheniformis (LSG1-1) and Bacillus subtilis (LSG2-1) were characterized and performed well in tolerance experiments. In addition, LSG1-1 and LSG2-1 were detected to have higher self-aggregation ability and surface hydrophobicity. In the in vitro adhesion model, LSG1-1 and LSG2-1 showed good adhesion ability and had obvious adhesion inhibitory effect on three pathogens of Aeromonas. Based on the characteristics observed so far, Bacillus licheniformis LSG1-1 and Bacillus subtilis LSG2-1 could form potential probiotic candidates in the digestive tract of R. lagowskii to help combat diseases in aquaculture.

Mucosal and systemic immune effects of Bacillus subtilis in rainbow trout (Oncorhynchus mykiss)

Bacillus spp. are well known for their probiotic properties. Hence, the long-term feeding of Bacillus spp. strains to different fish species has been proved to confer beneficial effects regarding growth or pathogen resistance, among others. However, whether these strains could function as mucosal adjuvants, up-regulating immune responses after a single administration, has not yet been investigated in fish. Thus, in the current work, we have performed a series of experiments in rainbow trout (Oncorhynchus mykiss) aimed at establishing the potential of two Bacillus subtilis spore-forming strains, designated as ABP1 and ABP2, as oral adjuvants/immunostimulants. As an initial step, we evaluated their transcriptional effects on the rainbow trout intestinal epithelial cell line RTgutGC, and in gut tissue explants incubated ex vivo with the two strains. Their capacity to adhere to RTgutGC cells was also evaluated by flow cytometry. Although both strains had the capacity to modulate the transcription of several genes related to innate and adaptive immune responses, it was the ABP1 strain that led to stronger transcriptional effects, also exerting a higher binding capacity to intestinal epithelial cells. Consequently, we selected this strain to establish its effects on splenic B cells upon in vitro exposure as well as to determine the transcriptional effects exerted in the spleen, kidney, and gut after a single oral administration of the bacteria. Our results showed that B. subtilis ABP1 had the capacity to modulate the proliferation, IgM secreting capacity and MHC II surface expression of splenic B cells. Finally, we confirmed that this strain also induced the transcription of genes involved in inflammation, antimicrobial genes, and genes involved in T cell responses upon a single oral administration. Our results provide valuable information regarding how B. subtilis modulates the immune response of rainbow trout, pointing to the usefulness of the ABP1 strain to design novel oral vaccination strategies for aquaculture.

Analysis of Probiotic Bacteria Genomes: Comparison of CRISPR/Cas Systems and Spacer Acquisition Diversity

Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes constitute an adaptive (acquired) defense system of bacteria and archaea. Here 72 probiotic bacteria genomes were investigated in terms of the presence of CRISPR/Cas systems and phage/plasmid invaders through spacer analysis. 49 CRISPR/Cas systems were detected within probiotic strains, namely,17 type II-A, 10 type I-C, 8 type I-E, 5 Type I-U (I-G), 4 type III-A, 2 type I-B, 1 type I-A, 1 type IV-B, and 1 type II-C. The predicted target of spacers was determined in 25 strains and consequently, three different spacer and target patterns were revealed. The diversity of CRISPR spacers provides insight and understanding to determine strain-specific invaders of probiotic bacteria as well as their relationships between strains. CRISPR systems were clarified in many studies for genomic characterization. However, recently, endogenous genome editing with CRISPR has provided an approach for various genome editing projects. Thus, in the future, producing strain-specific phage-resistant starter cultures or probiotics by endogenous genome editing methods according to phage/plasmid survey can be utilized for industrial and pharmaceutical applications. Therefore, this study intended a comprehensive investigation of CRISPR systems of probiotic bacteria.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12088-021-00971-1.

2'-Fucosyllactose promotes Lactobacillus rhamnosus KLDS 8001 to repair LPS-induced damage in Caco-2 cells

The aim of this study was to investigate the effect of 2'-fucosyllactose (2'-FL) on the repair of monolayer barrier damage in Caco-2 cells by Lactobacillus rhamnosus KLDS 8001 (KLDS 8001). The results showed that the addition of 2'-FL not only promoted the adhesion ability of KLDS 8001 to Caco-2 cells but also improved the anti-adhesive effect of pathogenic bacteria. Compared with 2'-FL or KLDS 8001 alone, 2'-FL+KLDS 8001 significantly reduced lipopolysaccharide (LPS)-induced malondialdehyde (MDA), lactate dehydrogenase (LDH) release, and cytokine (IL-1β, IL-6, and TNF-α) production. In addition, 2'-FL effectively promoted the transmembrane electrical resistance (TEER), cell viability, and cellular permeability of KLDS 8001 repaired damaged cells with dose-dependent properties. The mRNA and protein expression of Zonula Occludens-1 (ZO-1), Occludin, and Claudin-1 were also upregulated in the KLDS 8001 and 2'-FL co-treated treatment group. It was speculated that 2'-FL could effectively regulate the interaction between KLDS 8001 and intestinal epithelial cells to play a role in maintaining intestinal barrier function and avoiding pathogenic bacteria invasion. PRACTICAL APPLICATIONS: As the most widely used human milk oligosaccharides (HMOs), 2'-FL is vital for maintaining infant intestinal health. Our study found that the addition of 2'-FL promoted KLDS 8001 adhesion, anti-adhesion of pathogenic bacteria, anti-inflammatory capacity, repair of barrier damage, and tight junction protein expression, providing a new strategy to protect infant intestinal health and prevent various intestinal diseases.

Use of probiotics in the NICU: Evaluating the stability of a three-strain probiotic blend in various media for enteral feeding

BACKGROUND

There is little published data on how to prepare probiotic supplements for enteral delivery in the NICU. The objective of this study was to determine how a three-strain probiotic blend (Bb-02, TH-4® and BB-12®) would behave when mixed and held for 4 hours with saline water, sterile water, dextrose 5% in water (D5W), 24 kcal preterm formula, and human milk.

METHODS

A packet of a three-strain probiotic supplement was mixed with 3 mL of saline water, sterile water, D5W, 24 kcal preterm formula, and human milk (tested at 3 mL and 2 mL). Samples were stored at room temperature for 60 minutes then refrigerated for 180 minutes. Probiotic survival, using quantitative enumeration, and pH were monitored over 4 hours. Samples were passed through a 5 French (Fr) feeding tube at the end of the study to evaluate viscosity.

RESULTS

The largest variation in total cell count from 0-time was sterile water with a + 0.26 log(CFU)/mL change at 90 minutes and typical variation is considered±0.50 log units indicating no significant change between samples in 4 hours. Saline water had the lowest final pH at 4.88. All samples easily passed through a 5 Fr feeding tube.

CONCLUSION

The study showed minimal change in cell counts across solutions for 4 hours of storage, indicating health care facilities may be able to prepare probiotic supplements with a variety of solutions in pharmacies or milk rooms. This allows greater flexibility for probiotic delivery to preterm infants.

Genomic Stability and Phenotypic Characteristics of Industrially Produced Lacticaseibacillus rhamnosus GG in a Yogurt Matrix

Lacticaseibacillus rhamnosus GG is a widely marketed probiotic with well-documented probiotic properties. Previously, deletion of the mucus-adhesive spaCBA-srtC1 genes in dairy isolates was reported. In this study, we examined the genome preservation of industrially produced L. rhamnosus GG (DSM 33156) cofermented in yogurts. In total, DNA of 66 samples, including 60 isolates, was sequenced. Population samples and 59 isolates exhibited an intact genome. One isolate exhibited loss of spaCBA-srtC1. In addition, we examined phenotypes related to the probiotic properties of L. rhamnosus GG either from frozen pellets or cofermented in yogurt. L. rhamnosus GG from frozen pellets induced a response in intestinal barrier function in vitro, in contrast to frozen pellets of the starter culture. Yogurt matrix, containing only the starter culture, induced a response, but cofermentation with L. rhamnosus GG induced a higher response. Conversely, only the starter culture stimulated cytokine secretion in dendritic cells, and it was observed that the addition of L. rhamnosus GG to the starter culture reduced the response. We conclude that the L. rhamnosus GG genome is preserved in yogurt and that common in vitro probiotic effects of L. rhamnosus GG are observed when examined in the yogurt matrix. IMPORTANCE Lacticaseibacillus rhamnosus GG is a well-documented probiotic strain recognized for its high acid and bile tolerance and properties of adhesion to enterocytes and mucus. The strain exhibits SpaCBA pili, which have been demonstrated to play an important role in adhesion and therefore are relevant for persistence in the gastrointestinal tract. Recently we demonstrated that the genome and phenotypes of L. rhamnosus GG are preserved throughout an industrial production pipeline. However, as gene deletions in L. rhamnosus GG were previously reported for isolates from dairy products, a key question on the genomic stability of L. rhamnosus GG in a yogurt matrix remained. The aim of this study was to analyze genome stability and phenotypic characteristics of L. rhamnosus GG in yogurt. We found that the genome of L. rhamnosus GG is well conserved when the organism is cofermented in yogurt. Some phenotypic characteristics are consistent in all product matrixes, while other characteristics are modulated.

Microbiological Quality and Resistance to an Artificial Gut Environment of Two Probiotic Formulations

The quality control of probiotic products is the focus of numerous organizations worldwide. Several studies have highlighted the poor microbiological quality of many commercial probiotic formulations in terms of the identity of the contained microorganisms, viability, and purity, thus precluding the expected health benefits and representing a potential health risk for consumers. In this paper, we analyzed the contents of two probiotic formulations, one composed of an encapsulated mixture of lactobacilli and bifidobacteria, and one by a lyophilized yeast. The microorganisms contained in the products were quantified and identified using up-to-date methodologies, such as MALDI-TOF MS and metagenomic analysis. Moreover, as acid and bile tolerance is included among the criteria used to select probiotic microorganisms, in vitro tests were performed to evaluate the behavior of the formulations in conditions mimicking the harsh gastric environment and the intestinal fluids. Our results indicate the high quality of the formulations in terms of the enumeration and identification of the contained organisms, as well as the absence of contaminants. Moreover, both products tolerated the acidic conditions well, with encapsulation providing further protection for the microorganisms. A good tolerance to the simulated artificial intestinal conditions was also evidenced for both preparations.

Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota

Background

Auto-aggregation is a desired property for probiotic strains because it is suggested to promote colonization of the human intestine, to prevent pathogen infections and to modulate the colonic mucosa. We recently reported the generation of adapted mutants of Lactiplantibacillus plantarum NZ3400, a derivative of the model strain WCFS1, for colonization under adult colonic conditions of PolyFermS continuous intestinal fermentation models. Here we describe and characterize the emerge of an auto-aggregating phenotype in L. plantarum NZ3400 derivatives recovered from the modelled gut microbiota.

Results

L. plantarum isolates were recovered from reactor effluent of four different adult microbiota and from spontaneously formed reactor biofilms. Auto-aggregation was observed in L. plantarum recovered from all microbiota and at higher percentage when recovered from biofilm than from effluent. Further, auto-aggregation percentage increased over time of cultivation in the microbiota. Starvation of the gut microbiota by interrupting the inflow of nutritive medium enhanced auto-aggregation, suggesting a link to nutrient availability. Auto-aggregation was lost under standard cultivation conditions for lactobacilli in MRS medium. However, it was reestablished during growth on sucrose and maltose and in a medium that simulates the abiotic gut environment. Remarkably, none of these conditions resulted in an auto-aggregation phenotype in the wild type strain NZ3400 nor other non-aggregating L. plantarum, indicating that auto-aggregation depends on the strain history. Whole genome sequencing analysis did not reveal any mutation responsible for the auto-aggregation phenotype. Transcriptome analysis showed highly significant upregulation of LP_RS05225 (msa) at 4.1–4.4 log₂-fold-change and LP_RS05230 (marR) at 4.5–5.4 log₂-fold-change in all auto-aggregating strains compared to non-aggregating. These co-expressed genes encode a mannose-specific adhesin protein and transcriptional regulator, respectively. Mapping of the RNA-sequence reads to the promoter region of the msa-marR operon reveled a DNA inversion in this region that is predominant in auto-aggregating but not in non-aggregating strains. This strongly suggests a role of this inversion in the auto-aggregation phenotype.

Conclusions

L. plantarum NZ3400 adapts to the in vitro colonic environment by developing an auto-aggregation phenotype. Similar aggregation phenotypes may promote gut colonization and efficacy of other probiotics and should be further investigated by using validated continuous models of gut fermentation such as PolyFermS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02331-x.

Turbidimetric definition of growth limits in probiotic Lactobacillus strains from the perspective of an adaptation strategy

The application of an adaptation strategy for probiotics, which may improve their stress tolerance, requires the identification of the growth range for each parameter tested. In this study, 4 probiotics (Lactobacillus acidophilus, Lacticaseibacillus casei, Lacticaseibacillus rhamnosus, and Lactiplantibacillus plantarum) were grown under different pH, NaCl, and sucrose concentrations at 25°C, 30°C, and 37°C. Turbidimetric growth curves were carried out and lag phase duration, maximum growth rate, and amplitude (i.e., the difference between initial and stationary phase optical density) were estimated. Moreover, cell morphology was observed, and cell length measured. The growth response, as well as the morphological changes, were quite different within the 4 species. The L. acidophilus was the most sensitive strain, whereas L. plantarum was shown to better tolerate a wide range of stressful conditions. Frequently, morphological changes occurred when the growth curve was delayed. Based on the results, ranges of environmental parameters are proposed that can be considered suboptimal for each strain, and therefore could be tested. The quantitative evaluation of the growth kinetics as well as the morphological observation of the cells can constitute useful support to the choice of the parameters to be used in an adaptation strategy, notwithstanding the need to verify the effect on viability both in model systems and in foods.

Improving the Gut Microbiota with Probiotics and Faecal Microbiota Transplantation

Probiotics are “live strains of strictly selected microorganisms which, when administered in adequate amounts, confer a health benefit on the host”. After birth, our intestine is colonized by microbes like Escherichia coli, Clostridium spp., Streptococcus spp., Lactobacillus spp., Bacteroides spp., and Bifidobacterium spp. Our intestine is an extremely complex living system that participates in the protection of host through a strong defence against external aggregations. The microbial ecosystem of the intestine includes many native species of Bacteroides and Firmicutes that permanently colonize the gastrointestinal tract. The composition of flora changes over time depending upon diet and medical emergencies which leads to the diseased condition. Probiotics exert their mode of action by altering the local environment of the gut by competing with the pathogens, bacteriocins production, H2O2 production etc. Obesity is one of the major health problems and is considered as the most prevalent form of inappropriate nutrition. Probiotics like Lactobacillus Sp., Bifidobacterium Sp., Streptococcus Sp. are successfully used in the treatment of obesity proved in clinical trials. Faecal microbiota transplant (FMT), also known as a stool transplant, is the process of transplantation of Faecal bacteria from a healthy donor into a recipient’s gut to restore normal flora in the recipient. The therapeutic principle on which FMT works is microbes and their functions and metabolites produced by them which are used to treat a variety of diseases. The present review focuses on the role of gastrointestinal microbiome, probiotic selection criteria, their applications and FMT to treat diseases.

Complete genome sequence and probiotic properties of Lactococcus petauri LZys1 isolated from healthy human gut

Introduction. Lactococcus petauri LZys1 (L. petauri LZys1) is a type of lactic acid bacteria (LAB), which was initially isolated from healthy human gut.Hypothesis/Gap Statement. It was previously anticipated that L. petauri LZys1 has potential characteristics of probiotic properties. The genetic structure and the regulation functions of L. petauri LZys1 need to be better revealed.Aim. The aim of this study was to detect the probiotic properties L. petauri LZys1 and to reveal the genome information related to its genetic adaptation and probiotic profiles.Methodology. Multiple in vitro experiments were carried out to evaluate its lactic acid-producing ability, resistance to pathogenic bacterial strains, auto-aggregation and co-aggregation ability, and so on. Additionally, complete genome sequencing, gene annotation, and probiotic associated gene analysis were performed.Results. The complete genome of L. petauri LZys1 comprised of 1 985 765 bp, with a DNA G+C content of 38.07 %, containing 50 tRNA, seven rRNA, and four sRNA. A total of 1931 genes were classified into six functional categories by Kyoto Encyclopaedia of Genes and Genomes (KEGG) database. The neighbour-joining phylogeny tree based on the whole genome of L. petauri LZys1 and other probiotics demonstrated that L. petauri LZys1 has a significant similarity to Lactococcus garvieae. The functional genes were detected to expound the molecular mechanism and biochemical processes of its potential probiotic properties, such as atpB gene.Conclusion. All the results described in this study, together with relevant information previously reported, made L. prtauri LZys1 a very interesting potential strain to be considered as a prominent candidate for probiotic use.

Probiotic Properties of Lactobacillus Species Isolated from Fermented Palm Sap in Thailand

Lactic acid bacteria (LAB), which are the most frequently used probiotics in foods, confer health benefits such as antimicrobial activity, immune stimulation, and anticancer activity. Fermented palm sap is a potential source of LAB. This study aimed to evaluate in vitro antimicrobial and probiotic properties of LAB isolated from traditional fermented palm sap in Thailand. Among 40 isolated LAB species, 10 were preliminarily selected for their antimicrobial activity. These 10 isolates were identified and confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA sequencing as Lactobacillus paracasei (8/10), Lactobacillus fermentum (1/10), and Lactobacillus brevis (1/10). They were evaluated for probiotic characteristics and antimicrobial activities against pathogens. These isolates were tolerant toward simulated gastrointestinal tract conditions, including low pH, pepsin, pancreatin, and bile salts. The 10 isolates retained strong auto-aggregation and cell surface hydrophobicity, and they adhered tightly to human intestinal epithelial cells. The isolates were susceptible to ampicillin, erythromycin, clindamycin, tetracycline, and chloramphenicol but resistant to vancomycin, kanamycin, and streptomycin. Moreover, all isolates exhibited no hemolytic activity. All isolates exhibited good antibacterial activity against nine pathogenic bacteria. Thus, these 10 Lactobacillus isolates from fermented palm sap are promising potential candidates for use as probiotics in functional fermented foods and pharmaceutical products.

Screening beneficial bacteriostatic lactic acid bacteria in the intestine and studies of bacteriostatic substances

Lactic acid bacteria (LAB) are a representative probiotic. As the dominant flora in the human intestinal tract, LAB can regulate the balance of human intestinal flora and improve host health. The purpose of this study was to isolate and screen LAB that are well suited to the intestinal characteristics of the Chinese population, with excellent probiotics and high antibacterial activity. After 16S ribosomal RNA (rRNA) homology and phylogenetic tree analysis, potential probiotics were tested for their antibacterial activity, resistance to artificial gastrointestinal fluid and drugs, surface hydrophobicity, and safety. Three strains of LAB with acid resistance, bile salt resistance, epithelial cell adhesion, and no multidrug resistance were selected: Lactobacillus salivarius, Leuconostoc lactis, and Lactobacillus paracasei. Analysis of the antibacterial active substances in the three strains and their fermentation broths revealed that the main antibacterial substances of L. lactis were organic acids, whereas those of L. salivarius and L. paracasei were organic acids and bacteriocins with broad-spectrum antibacterial activity. These three strains of probiotic LAB with high antibacterial activity were identified as bacterial resources that could potentially be used to develop probiotic preparations for the prevention and treatment of intestinal diseases caused by intestinal pathogens.

Dairy-Derived and Egg White Proteins in Enhancing Immune System Against COVID-19

Coronavirus disease (COVID-19) is a global health challenge, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) triggers a plethora of respiratory disturbances and even multiple organs failure that can be fatal. Nutritional intervention is one of the key components toward to a proper management of COVID-19 patients, especially in those requiring medication, and should thus be considered the first-line treatment. Immuno-modulation and -stimulation are currently being explored in COVID-19 management and are gaining interest by food and pharmaceutical industries. Various dietary combinations, bioactive components, nutrients and fortified foods have been reported to modulate inflammation during disease progression. Dietary combinations of dairy-derived products and eggs are gaining an increasing attention given the huge immunomodulatory and anti-inflammatory properties attributed to some of their chemical constituents. Eggs are complex dietary components containing many essential nutrients and bioactive compounds as well as a high-quality proteins. Similarly, yogurts can replenish beneficial bacteria and contains macronutrients capable of stimulating immunity by enhancing cell immunity, reducing oxidative stress, neutralizing inflammation and regulating the intestinal barriers and gut microbiome. Thus, this review highlights the impact of nutritional intervention on COVID-19 management, focusing on the immunomodulatory and inflammatory effects of immune-enhancing nutrients.

Probiotics and Amelioration of Rheumatoid Arthritis: Significant Roles of Lactobacillus casei and Lactobacillus acidophilus

Rheumatoid arthritis is a chronic autoimmune disorder that can lead to disability conditions with swollen joints, pain, stiffness, cartilage degradation, and osteoporosis. Genetic, epigenetic, sex-specific factors, smoking, air pollution, food, oral hygiene, periodontitis, Prevotella, and imbalance in the gastrointestinal microbiota are possible sources of the initiation or progression of rheumatoid arthritis, although the detailed mechanisms still need to be elucidated. Probiotics containing Lactobacillus spp. are commonly used as alleviating agents or food supplements to manage diarrhea, dysentery, develop immunity, and maintain general health. The mechanism of action of Lactobacillus spp. against rheumatoid arthritis is still not clearly known to date. In this narrative review, we recapitulate the findings of recent studies to understand the overall pathogenesis of rheumatoid arthritis and the roles of probiotics, particularly L. casei or L. acidophilus, in the management of rheumatoid arthritis in clinical and preclinical studies.

Dietary Supplementation with Enterococcus faecium R1 Attenuates Intestinal and Liver Injury in Piglets Challenged by Lipopolysaccharide

Simple Summary

The biological characteristics of E. faecium R1 and the effect of dietary supplementation with E. faecium R1 on the growth performance of weaned piglets were studied. The results showed that E. faecium R1 had the characteristics of effective bacteriostatic activity, acid resistance, bile salt resistance, and high-temperature resistance. Dietary supplementation with E. faecium R1 (6.5 × 10⁶ CFU/g) improved intestinal function of weaning piglets by decreasing diarrhea incidence. Further research found that dietary supplementation with E. faecium R1 (6.5 × 10⁶ CFU/g) attenuated intestinal and liver injury in piglets challenged by lipopolysaccharide.

Abstract

In this study, a strain of E. faecium R1 with effective bacteriostatic activity, acid resistance, bile salt resistance, high-temperature resistance was screened. To study the effect of E. faecium R1 on lipopolysaccharide (LPS)-induced intestinal and liver injury in piglets, twenty-four weaned female piglets were randomly assigned into one of three groups (8 piglets per group). Piglets in the control group and LPS group were fed a basal diet, piglets in the E. faecium group were fed the basal diet supplemented with E. faecium R1 (6.5 × 10⁶ CFU/g). On day 21 of the trial, piglets in the LPS group and E. faecium group were intraperitoneally administered LPS (100 μg/kg), piglets in the control group were administered the same volume of saline. Subsequently, blood samples were collected at 3 h, and intestinal, liver, and pancreas samples were collected at 6 h. Results showed that E. faecium R1 supplementation significantly decreased the diarrhea rate and feed to gain ratio, and dramatically reduced LPS-induced intestinal and liver injury in piglets. Compared with the LPS group, E. faecium R1 supplementation significantly increased the content of glucagon in plasma and IL-1β in the liver, and the mRNA levels of villin in jejunum and ileum and Bcl-xL and pBD-L in the ileum, and significantly decreased the contents of prostaglandin 2 and malondialdehyde in the liver and the activities of myeloperoxidase and aspartate aminotransferase in plasma in piglets. Moreover, E. faecium R1 improved the pancreatic antioxidant capacity in piglets, which was indicated by a significant increase in catalase activity and a decrease in total nitric oxide synthase activity. In summary, dietary supplementation with E. faecium R1 alleviates intestinal and liver injury in LPS-challenged piglets.

Deciphering the Probiotic Potential of Bacillus amyloliquefaciens COFCAU_P1 Isolated from the Intestine of Labeo rohita Through In Vitro and Genetic Assessment

In this study, a bacterial strain COFCAU_P1, isolated from the digestive tract of a freshwater teleost rohu (Labeo rohita), was identified as Bacillus amyloliquefaciens using 16S rRNA gene sequence analysis combined with amplification of species-specific BamHI and barnase genes. The probiotic potential of the strain was evaluated using an array of in vitro tests along with safety and genetic analyses. The isolate showed potent antimicrobial response against several fish pathogenic bacteria, survived a wide pH range (2-9), and was resistant up to 10% bile salt concentration. With regard to the in vitro adhesion properties, the strain showed significantly high in vitro adhesion to mucus, auto and co-aggregation capacity, and cell surface hydrophobicity. The strain was non-haemolytic, able to produce extracellular enzymes, viz., proteinase, amylase, lipase, and cellulase, and showed significant free radical scavenging activity. A challenge study in rohu revealed the strain COFCAU_P1 as non-pathogenic. The presence of putative probiotic marker genes including 2, 3-bisphosphoglycerate-independent phosphoglycerate mutase, arginine/ornithine antiporter ArcD, choloylglycine hydrolase, LuxS, and E1 β-subunit of the pyruvate dehydrogenase complex was confirmed by PCR, suggesting the molecular basis of the probiotic-specific functional attributes of the isolate. In conclusion, the in vitro and genetic approaches enabled the identification of a potential probiotic from autochthonous source with a potential of its utilization in the aquaculture industry.

ODFM, an omics data resource from microorganisms associated with fermented foods

ODFM is a data management system that integrates comprehensive omics information for microorganisms associated with various fermented foods, additive ingredients, and seasonings (e.g. kimchi, Korean fermented vegetables, fermented seafood, solar salt, soybean paste, vinegar, beer, cheese, sake, and yogurt). The ODFM archives genome, metagenome, metataxonome, and (meta)transcriptome sequences of fermented food-associated bacteria, archaea, eukaryotic microorganisms, and viruses; 131 bacterial, 38 archaeal, and 28 eukaryotic genomes are now available to users. The ODFM provides both the Basic Local Alignment Search Tool search-based local alignment function as well as average nucleotide identity-based genetic relatedness measurement, enabling gene diversity and taxonomic analyses of an input query against the database. Genome sequences and annotation results of microorganisms are directly downloadable, and the microbial strains registered in the archive library will be available from our culture collection of fermented food-associated microorganisms. The ODFM is a comprehensive database that covers the genomes of an entire microbiome within a specific food ecosystem, providing basic information to evaluate microbial isolates as candidate fermentation starters for fermented food production.