Analysis of the microbial content of probiotic products commercialized worldwide and survivability in conditions mimicking the human gut environment

Development of reference-based model for improved analysis of bacterial community

Probiotic bacteria play a vital role in maintaining gut microbial homeostasis and are widely used in various commercial products. Although 16S rRNA amplicon-based next-generation sequencing (NGS) is commonly used to analyze probiotic products, biases can arise from various 16S rRNA amplification regions, sequencing platforms, and library kits. In this study, a reference-based bias correction model was developed to correct sequencing biases. The model was validated using eight mock communities and 12 commercial products, which were analyzed across multiple NGS platforms and various 16S rRNA regions. Specific primer-probe assays were developed for accurate bacterial quantification, and their specificity was validated and used in conjunction with droplet digital PCR (ddPCR) to establish initial bacterial ratios within communities. Analysis of the mock communities revealed platform- and region-specific biases, with specific species consistently over- or under-represented. Similarly, commercial product analyses have shown biased outcomes owing to varying sequencing protocols. The correction model, based on PCR efficiencies from the reference communities, successfully corrected biased ratios across different amplification regions and platforms to achieve results that closely matched the proportions predicted by ddPCR. The model effectively corrected the biases arising from the different polymerases. Notably, partial references containing approximately 40 % of the species achieved correction results that were comparable to those of the complete references. This approach demonstrates the potential for improving microbiome analysis accuracy within predictable ranges, and could serve as a model for addressing sequencing bias in metagenomic research.

Neonatal administration of Lactiplantibacillus plantarum ATCC 202195 with or without fructooligosaccharide in Bangladesh: a placebo-controlled randomized trial

Lactiplantibacillus plantarum ATCC 202195 (LP202195) plus fructooligosaccharide (FOS) for 7 days was previously shown to colonize the infant intestine up to 6 months of age and reduced sepsis rates among young infants in rural India. In a phase 2 randomized controlled trial in Dhaka, Bangladesh (N = 519), neonatal administration of LP202195 for 1 or 7 days, with or without FOS, increased LP202195 stool abundance from 14 to 60 days of age, versus placebo. Abundance progressively declined in the post-administration period and did not persist beyond 2 months of age. FOS did not affect LP202195 abundance or its duration of persistence. All regimens were well-tolerated and safe. The absence of LP202195 colonization was inconsistent with results from a prior trial. Additional large-scale trials of LP202195 ± FOS are needed to establish its efficacy in infants who do not become LP202195-colonized.

IMPORTANCE

Among infants born in Dhaka, Bangladesh, a 7-day regimen of Lactiplantibacillus plantarum ATCC 202195 (LP202195) plus fructooligosaccharide (FOS) did not colonize the infant gastrointestinal (GI) tract. The absence of colonization is inconsistent with a prior study of the same synbiotic regimen in India, in which LP202195 was shown to persist in the infant GI tract for up to 6 months. Sustained LP202195 colonization was thought to be required for the probiotic to impart its beneficial impact on newborn sepsis. Therefore, additional trials are warranted to confirm the previously observed effects of LP202195 on infant clinical outcomes in the absence of LP202195 colonization. Moreover, since regimens of LP202195 that did not include FOS were indistinguishable from the synbiotic in terms of colonization, safety, and tolerability, future trials should assess the role of FOS for clinical efficacy; removing FOS would reduce costs, an important consideration for scale-up.

CLINICAL TRIALS

This study has been registered at ClinicalTrials.gov as NCT05180201.

Mechanism of Action and Beneficial Effects of Probiotics in Amateur and Professional Athletes

Probiotics are live microorganisms that, when administered in adequate amounts, provide health benefits to the host. According to the International Society of Sports Nutrition (ISSN), probiotic supplementation can optimize the health, performance, and recovery of athletes at all stages of their careers. Recent research suggests that probiotics can improve immune system functions, reduce gastrointestinal distress, and increase gut permeability in athletes. Additionally, probiotics may provide athletes with secondary health benefits that could positively affect athletic performance through enhanced recovery from fatigue, improved immune function, and maintenance of healthy gastrointestinal tract function. The integration of some probiotic strains into athletes' diets and the consumption of multi-strain compounds may lead to an improvement in performance and can positively affect performance-related aspects such as fatigue, muscle pain, body composition, and cardiorespiratory fitness. In summary, probiotics can be beneficial for athletes at all stages of their careers, from amateur to professional. This paper reviews the progress of research on the role of probiotic supplementation in improving energy metabolism and immune system functions, reducing gastrointestinal distress, and enhancing recovery from fatigue in athletes at different levels.

The Effect of Food Matrix Taken with Probiotics on the Survival of Commercial Probiotics in Simulation of Gastrointestinal Digestion

The adequate survival of probiotics in the harsh environment of the gastrointestinal (GI) tract plays a crucial role in the expression of their functional properties. The aim of the present study was to evaluate the survival of commercial probiotics during digestion using a standardised INFOGEST 2.0 model extended with three food matrices simulating three scenarios for the consumption of probiotics: on an empty stomach, with juice, or with food (porridge). All eight products matched the bacterial content stated on the label. After simulated digestion, we observed an average decrease in viability of 1.6 log10 colony forming units (CFU) when the product was co-digested with water, a 2.5 log10 CFU decrease in the presence of juice, and a 1.2 log10 CFU decrease in the presence of porridge. The survival rate of the probiotics was statistically higher in the test samples with porridge (91.8%) than in those with juice (79.0%). For two products, the number of lactobacilli and bifidobacteria strains after digestion was less than <3 × 105 CFU, which can be considered insufficient. The present study has shown that the survival of probiotic strains during GI passage depends not only on their ability to withstand these harsh conditions but may also be influenced by the manufacturing process and by the foods consumed together with the probiotics.

Strain-Dependent Adhesion Variations of Shouchella clausii Isolated from Healthy Human Volunteers: A Study on Cell Surface Properties and Potential Probiotic Benefits

The probiotic potential of Shouchella clausii is widely recognized, but little is known about its adhesive properties. Hence, this study aims to investigate the adhesion potential and cell surface properties of four human-origin S. clausii strains (B619/R, B603/Nb, B106, and B637/Nm). We evaluated epithelial adhesion, Extracellular Matrix (ECM) binding, aggregation ability, and cell surface hydrophobicity and used genome analysis for validation. Our results demonstrate that adhesion capability is a strain-specific attribute, with significant variations observed among the four strains. B619/R, B603/Nb, and B106 displayed stronger adhesion properties than B637/Nm. Supplementary adhesion assays showed that B637/Nm displayed high hydrophobicity, significant auto-aggregation, and significant mucin-binding abilities. Conversely, B619/R, B603/Nb, and B106 had mildly hydrophobic surfaces and low aggregation abilities. Genome annotation revealed the presence of various adhesion proteins in four strains. Notably, the reduced adhesion potential of B637/Nm was supported by the absence of the cell wall surface anchor family protein (LPxTG motif), which is crucial for interactions with intestinal epithelial cells or mucus components. Further, docking studies provided insights into the interaction of adhesion proteins with gut mucins. These findings contribute to a better understanding of how S. clausii strains interact with the gut environment, facilitating the development of probiotic formulations tailored for improved gut health and well-being.

Both live and heat killed Lactiplantibacillus plantarum DPUL-F232 alleviate whey protein-induced food allergy by regulating cellular immunity and repairing the intestinal barrier

Postbiotics have been proposed as clinically viable alternatives to probiotics, addressing limitations and safety concerns associated with probiotic use. However, direct comparisons between the functional differences and health benefits of probiotics and postbiotics remain scarce. This study compared directly the desensitization effect of probiotics and postbiotics derived from Lactiplantibacillus plantarum strain DPUL-F232 in the whey protein-induced allergic rat model. The results demonstrate that administering both live and heat killed F232 significantly alleviated allergy symptoms, reduced intestinal inflammation, and decreased serum antibody and histamine levels in rats. Both forms of F232 were effective in regulating the Th1/Th2 balance, promoting the secretion of the regulatory cytokine IL-10, inhibiting mast cell degranulation and restoring the integrity of the intestinal barrier through the upregulation of tight junction proteins. Considering the enhanced stability and reduced safety concerns of postbiotics compared to probiotics, alongside their ability to regulate allergic reactions, we suggest that postbiotics may serve as viable substitutes for probiotics in managing food allergies and potentially other diseases.

Fine-tuning the gut ecosystem: the current landscape and outlook of artificial microbiome therapeutics

The gut microbiome is acknowledged as a key determinant of human health, and technological progress in the past two decades has enabled the deciphering of its composition and functions and its role in human disorders. Therefore, manipulation of the gut microbiome has emerged as a promising therapeutic option for communicable and non-communicable disorders. Full exploitation of current therapeutic microbiome modulators (including probiotics, prebiotics, and faecal microbiota transplantation) is hindered by several factors, including poor precision, regulatory and safety issues, and the impossibility of providing reproducible and targeted treatments. Artificial microbiota therapeutics (which include a wide range of products, such as microbiota consortia, bacteriophages, bacterial metabolites, and engineered probiotics) have appeared as an evolution of current microbiota modulators, as they promise safe and reproducible effects, with variable levels of precision via different pathways. We describe the landscape of artificial microbiome therapeutics, from those already on the market to those still in the pipeline, and outline the major challenges for positioning these therapeutics in clinical practice.

Anti-Staphylococcal Biofilm Effects of a Liposome-Based Formulation Containing Citrus Polyphenols

Biofilms are surface-associated microbial communities embedded in a matrix that is almost impenetrable to antibiotics, thus constituting a critical health threat. Biofilm formation on the cornea or ocular devices can lead to serious and difficult-to-treat infections. Nowadays, natural molecules with antimicrobial activity and liposome-based delivery systems are proposed as anti-biofilm candidates. In this study, the anti-biofilm activity of a formulation containing citrus polyphenols encapsulated in liposomes was evaluated against Staphylococcus aureus and Staphylococcus epidermidis, the most common agents in ocular infections. The formulation activity against planktonic staphylococci was tested by broth microdilution and sub-inhibitory concentrations were used to evaluate the effect on biofilm formation using the crystal violet (CV) assay. The eradicating effect of the preparation on mature biofilms was investigated by the CV assay, plate count, and confocal laser scanning microscopy. The product was bactericidal against staphylococci at a dilution of 1:2 or 1:4 and able to reduce biofilm formation even if diluted at 1:64. The formulation also had the ability to reduce the biomass of mature biofilms without affecting the number of cells, suggesting activity on the extracellular matrix. Overall, our results support the application of the used liposome-encapsulated polyphenols as an anti-biofilm strategy to counter biofilm-associated ocular infections.

Quality Management of Probiotics: Ensuring Safety and Maximizing Health Benefits

Consumption of probiotics, which are beneficial live microorganisms, has received a lot of attention because of their potential to improve health and wellness. Robust quality control measures are necessary to ensure the safety of probiotics and maximize their health effects. This review delves into the topic of quality management in probiotics, highlighting the significance of sticking to strict guidelines from manufacture to storage to distribution. Probiotic quality standards, Good Manufacturing Practices (GMP) implementation, quality control and testing techniques, and documentation and traceability systems are all discussed in detail. The importance of taking precautions to avoid microbial contamination, meeting all applicable regulations, and clearly marking and packaging probiotic products is also emphasized. In addition, it reviews the clinical evidence supporting the possible health advantages of probiotics and investigates the processes through which probiotics enhance health. The review continues by stressing the significance of educating and informing consumers about probiotics and their proper use in order to maximize health benefits. Probiotics' potential health benefits can be maximized and consumer faith in these helpful microbes can be bolstered by adopting thorough quality management measures to ensure their safety, efficacy, and consistency.