Biofilm Forming Lactobacillus: New Challenges for the Development of Probiotics

The roles of functional bacterial amyloids in neurological physiology and pathophysiology: Pros and cons for neurodegeneration

Bacterial biofilms, which are complex communities of microorganisms encapsulated in a self-produced extracellular matrix, play critical roles in various diseases. Recent research has underscored the dualistic nature of amyloids, structural proteins within these biofilms, in human health, particularly highlighting the significant role in neurodegenerative disorders such as Alzheimer's (AD) and Parkinson's disease (PD). These amyloids modulate the immune response by inducing the production of interleukin-10 (IL-10), which plays a role in anti-inflammatory processes. Additionally, they inhibit the aggregation of human amyloids and enhance the integrity of the intestinal barrier. Detrimentally, they exacerbate neuroinflammation by elevating inflammatory cytokines and promoting the aggregation of human amyloid proteins-amyloid-β (Aβ) in AD and α-synuclein (αS) in PD-through a process known as cross-seeding. Moreover, bacterial amyloids have also been shown to stimulate the production of anti-curli/DNA antibodies, which are implicated in the pathogenesis of autoimmune diseases. Given their dualistic nature, bacterial amyloids may, under specific conditions, function as beneficial proteins for human health. This understanding holds promise for the development of targeted therapeutic strategies aimed at modulating bacterial amyloids in the context of neurodegenerative diseases, such as AD and PD.

Comparative Analysis of the Probiotic Features of Lysinibacillus and Enterobacter Strains Isolated from Gut Tract of Triploid Cyprinid Fish

Gut mucosal immunity of teleost is mainly governed by mucosa-associated lymphoid tissues (MALT) and indigenous microbiota on mucosal surfaces of gut tract, which can confer protection against pathogenic invasion. However, the probiotic features of bacterial isolates from gut tract of triploid cyprinid fish (TCF) were largely unclear. In this study, Lysinibacillus and Enterobacter strains were isolated for probiotic identification. Whole genome sequencing (WGS) analysis indicated that Lysinibacillus and Enterobacter isolates possessed a variety of functional genes associated with probiotic features. Biofilm-forming activity (BFA) were one of the most important probiotic features, which can enable probiotic strains to communicate with indigenous microbiota by forming sessile community and then confer protection against stressors and invading pathogens. In this study, Lysinibacillus and Enterobacter isolates displayed high levels of BFA, hydrophobicity as well as aggregating potentials. Moreover, supernatants of probiotic isolates not only decreased pathogenic BFA and growth activity, but also showed high decomposing activity to macronutrients. These results indicated that probiotic isolates from gut tract of TCFs may pose protective roles in health of farmed fish.

Regulatory mechanisms and applications of Lactobacillus biofilms in the food industry

Lactobacillus is widely recognized for its probiotic benefits and has been widely used in food production. While biofilms are typically associated with pathogenic bacteria, they also served as a self-protective mechanism formed by microorganisms in an adverse environments. In recent years, relevant studies have revealed the excellent characteristics of Lactobacillus biofilms, offering new insights into their potential applications in the food industry. The Lactobacillus biofilms is important in improving fermentation processes and enhancing the resilience of Lactobacillus in various conditions. This paper reviews how quorum sensing regulates the formation of Lactobacillus biofilms and explores their roles in stress resistance, bacteriostasis and food production. Additionally, it highlights the emerging concept of fourth-generation probiotics, developed through biofilm technology, as a novel approach to probiotic applications.

3D-Bioprinted Urinary Catheters Enable Sustained Probiotic Recovery Under Flow and Improve Bladder Colonization In Vivo

Catheter-associated urinary tract infections (CAUTIs) account for a large proportion of healthcare-associated infections. CAUTIs, caused by colonization of the catheter surface by uropathogens, are challenging to treat, especially when compounded by antibiotic resistance. One prophylactic strategy that could reduce pathogen colonization is bacterial interference, whereby the catheter surface is coated with non-pathogenic bacteria. Current challenges include identifying appropriate bacterial interference strains that maintain stable association with the catheter and are viable, but not pathogenic, in the urinary tract environment. This study evaluated the stability of probiotic Lactobacillus rhamnosus in 3D bioprints mimicking urinary catheter tubing under urine flow and assessed viability and safety in an in vivo mouse model. Bioprints underwent hydraulic flow testing in vitro with artificial urine media (AUM), followed by evaluation of catheter structure, L. rhamnosus recovery, and biofilm formation. Mice were inoculated with free L. rhamnosus bacteria or implanted with L. rhamnosus-containing bioprints to measure urinary tract colonization and assess effects on the bladder tissue. Bioprinted segments exhibited minimal mass change while maintaining an intact shape and demonstrated viable L. rhamnosus recovery throughout 7 days. L. rhamnosus formed biofilms on the bioprint surface that were not disrupted by urinary flow conditions. Encouragingly, L. rhamnosus viability was maintained in bioprints in a mouse urinary tract catheterization model. Bioprints released L. rhamnosus in vivo and did not cause histological inflammation beyond that generated by standard silicone catheters. In summary, L. rhamnosus bioprints exhibited key desirable characteristics, including maintenance of probiotic viability, probiotic growth on the catheter surface, and enhanced probiotic colonization of the bladder. This study supports the development of bioprinted probiotic catheters as a new strategy to prevent CAUTI.

Microbial cell-type-based grouping model as a potential indicator of cervicovaginal flora prone to biofilm formation

Cervicovaginal (CV) microbiota is critical for the well-being of host. We investigated the relationship between the ratio of Lactobacilli (LB) and cocci/coccobacilli (C/CB)-type microbial cells with biofilm formation of CV mixed cultures of women with no inflammation/infection or any epithelial abnormalities in Pap-stained smears Group 1 (G1) corresponds to the flora with LB-type cells alone, whereas G2 corresponds to the LB-dominated flora. G3 contains balanced LB and C/CB cells and G4 is dominated with C/CB. G5 corresponds to a flora with C/CB-type cells alone. Biofilm formation of CV mixed cultures was assessed by crystal violet binding assay and optical density (OD)≥0.8 were defined as biofilm producers. G1 and G3 exist in higher frequencies compared to the other smear groups. However, although the frequency of G5 dominated with C/CB-type cells were the lowest (4%); biofilm formation in that group was observed in the highest frequency (42.9%). The least biofilm formation frequency was observed in G3 smears with balanced flora (1%). Biofilm formation in healthy CV flora increases when there becomes an imbalance between LB and C/CB-type cells and an increase in C/CB-type cells. Our approach may enable early detection of vaginal dysbiosis in healthy flora prone to biofilm-associated CV infections such as bacterial vaginosis (BV).

Sucrose contributed to the biofilm formation of Tetragenococcus halophilus and changed the biofilm structure

Based on the previous research results that the addition of sucrose in the medium improved the biofilm formation of Tetragenococcus halophilus, the influence of sucrose on biofilm formation was explored. Moreover, the influence of exogenous expression of related genes sacA and galE from T. halophilus on the biofilm formation of L. lactis NZ9000 was investigated. The results showed that the addition of sucrose in the medium improved the biofilm formation, the resistance of biofilm cells to freeze-drying stress, and the contents of exopolysaccharides (EPS) and eDNA in the T. halophilus biofilms. Meanwhile, the addition of sucrose in the medium changed the monosaccharide composition of EPS and increased the proportion of glucose and galactose in the monosaccharide composition. Under 2.5% (m/v) salt stress condition, the expression of gene sacA promoted the biofilm formation and the EPS production of L. lactis NZ9000 with the sucrose addition in the medium and changed the EPS monosaccharide composition. The expression of gene galE up-regulated the proportion of rhamnose, galactose, and arabinose in the monosaccharide composition of EPS, and down-regulated the proportion of glucose and mannose. This study will provide a theoretical basis for regulating the biofilm formation of T. halophilus, and provide a reference for the subsequent research on lactic acid bacteria biofilms.

Microbial biofilms: a comprehensive review of their properties, beneficial roles and applications

Biofilms are microbial communities nested in self-secreted extracellular polymeric substances that can provide microorganisms with strong tolerance and a favorable living environment. Deepening the understanding and research on positive effects of microbial biofilms is consequently necessary, since most researches focuses on how to control biofilms formation to reduce food safety issues. This paper highlights beneficial roles of biofilms including the formation mechanism, influencing factors, health benefits, strategies to improve its film-forming efficiency, as well as applications especially in fields of food industry, agriculture and husbandry, and environmental management. Beneficial biofilms can be affected by multiple factors such as strain characteristics, media composition, signal molecules, and carrier materials. The biofilm barrier composed of beneficial bacteria provides a more favorable microecological environment, keeping bacteria survival longer, and its derived metabolites are better conducive to health. However, in the practical application of biofilms, there are still significant challenges, especially in terms of film-forming efficiency, stability, and safety assessment. Continuous research is needed to discover innovative methods of utilizing biofilms for sustainable food development in the future, in order to fully unleash its potential and promote its application in the food industry.

Assessment of Biofilm Formation and Anti-Inflammatory Response of a Probiotic Blend in a Cultured Canine Cell Model

Gut dysbiosis and an inflamed bowel are growing concerns in mammals, including dogs. Probiotic supplements have been used to restore the natural microbial community and improve gastrointestinal health. Biofilm formation, antimicrobial activities, and immunological responses of probiotics are crucial to improving gut health. Thus, we tested a commercial probiotic blend (LabMAX-3), a canine kibble additive comprising Lactobacillus acidophilus, Lacticaseibacillus casei, and Enterococcus faecium for their ability to inactivate common enteric pathogens; their ability to form biofilms; epithelial cell adhesion; and their anti-inflammatory response in the Madin-Darby Canine Kidney (MDCK) cell line. Probiotic LabMAX-3 blend or individual isolates showed a strong inhibitory effect against Salmonella enterica, Listeria monocytogenes, enterotoxigenic Escherichia coli, and Campylobacter jejuni. LabMAX-3 formed biofilms comparable to Staphylococcus aureus. LabMAX-3 adhesion to the MDCK cell line (with or without lipopolysaccharide (LPS) pretreatment) showed comparable adhesion and biofilm formation (p < 0.05) to L. casei ATCC 334 used as a control. LabMAX-3 had no cytotoxic effects on the MDCK cell line during 1 h exposure. The interleukin-10 (IL-10) and tumor necrosis factor alpha (TNFα) ratio of LabMAX-3, compared to the L. casei control, showed a significant increase (p < 0.05), indicating a more pronounced anti-inflammatory response. The data show that LabMAX-3, a canine kibble supplement, can improve gastrointestinal health.

Aging-induced dysbiosis worsens sepsis severity but is attenuated by probiotics in D-galactose-administered mice with cecal ligation and puncture model

INTRODUCTION

Despite the well-established effects of aging on brain function and gut dysbiosis (an imbalance in gut microbiota), the influence of aging on sepsis-associated encephalopathy (SAE) and the role of probiotics in this context remain less understood.

METHODS

C57BL/6J mice (8-week-old) were subcutaneously administered with 8 weeks of D-galactose (D-gal) or phosphate buffer solution (PBS) for aging and non-aging models, respectively, with or without 8 weeks of oral Lacticaseibacillus rhamnosus GG (LGG). Additionally, the impact of the condition media from LGG (LCM) was tested in macrophages (RAW 264.7 cells), microglia (BV-2 cells), and hippocampal cells (HT-22 cells).

RESULT

Fecal microbiome analysis demonstrated D-gal-induced dysbiosis (reduced Firmicutes and Desulfobacterota with increased Bacteroidota and Verrucomicrobiota), which LGG partially neutralized the dysbiosis. D-gal also worsens cecal ligation and puncture (CLP) sepsis severity when compared with PBS-CLP mice, as indicated by serum creatinine (Scr) and alanine transaminase (ALT), but not mortality, neurological characteristics (SHIRPA score), and serum cytokines (TNF-α and IL-6). Additionally, D-gal-induced aging was supported by fibrosis in the liver, kidney, and lung; however, CLP sepsis did not worsen fibrosis. Interestingly, LGG attenuated all parameters (mortality, Scr, ALT, SHIRPA, and cytokines) in non-aging sepsis (PBS-CLP) while improving all these parameters, except for mortality and serum IL-6, in aging sepsis (D-gal CLP). For the in vitro test using lipopolysaccharide (LPS) stimulation, LCM attenuated inflammation in some parameters on RAW264.7 cells but not BV-2 and HT-22 cells, implying a direct anti-inflammatory effect of LGG on macrophages, but not in cells from the brain.

CONCLUSION

D-gal induced fecal dysbiosis and worsened sepsis severity as determined by Scr and ALT, and LGG could alleviate most of the selected parameters of sepsis, including SAE. However, the impact of LGG on SAE was not a direct delivery of beneficial molecules from the gut to the brain but partly due to the attenuation of systemic inflammation through the modulation of macrophages.

Biofilm formation of Lactiplantibacillus plantarum food isolates under flow and resistance to disinfectant agents

Bacterial biofilms formed in food processing environments can be resilient against cleaning and disinfection causing recontamination and spoilage of foods. We investigated the biofilm formation of six Lactiplantibacillus plantarum food spoilage isolates (FBR1-FBR6) using WCFS1 as a reference strain, and examined the impact of benzalkonium chloride (BKC) and peracetic acid (PAA) on planktonic and biofilm cells formed under static and dynamic flow conditions. We used a custom-designed setup composed of a 48-well plate with 0.8 ml culture volumes. We quantified biofilm formation under static and dynamic flow conditions with a flow rate of 3.2 ml/h using plate counting, Crystal Violet (CV) staining, and fluorescence staining techniques. Our findings revealed significant differences in biofilm formation and disinfectant resistance among studied strains and cell types. We observed that flow promoted biofilm formation in some strains and increased the number of culturable cells within biofilms in all strains. Furthermore, biofilm cells demonstrated higher resistance to disinfectants in comparison to planktonic cells for certain strains. Interestingly, cells from dispersed under flow biofilms show higher resistance to disinfectants than cells from static biofilms. The results indicate the importance of flow conditions in influencing L. plantarum food isolates biofilm formation and disinfection resistance, which may have implications for product contamination and spoilage risks.

Unlocking the potential of lactic acid bacteria mature biofilm extracts as antibiofilm agents

The continuous growth of biofilm infections and their resilience to conventional cleaning methods and antimicrobial agents pose a worldwide challenge across diverse sectors. This persistent medical, industrial, and environmental issue contributes to treatment challenges and chronic diseases. Lactic acid bacteria have garnered global attention for their substantial antimicrobial effects against pathogens and established beneficial roles. Notably, their biofilms are also predicted to show a promising control strategy against pathogenic biofilm formation. The prevalence of biofilm-related problems underscores the need for extensive research and innovative solutions to tackle this global challenge. This novel study investigates the effect of different extracts (external, internal, and mixed extracts) obtained from Lactobacillus rhamnosus GG biofilm on pathogenic-formed biofilms. Subsequently, external extracts presented an important eradication effectiveness. Furthermore, a 6-fold concentration of these extracts led to eradication percentages of 57%, 67%, and 76% for Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa biofilms, respectively, and around 99.9% bactericidal effect of biofilm cells was observed for the three strains. The results of this research could mark a significant breakthrough in the field of anti-biofilm and antimicrobial strategies. Further studies and molecular research will be necessary to detect the molecules secreted by the biofilm, and their mechanisms of action engaged in new anti-biofilm strategies.

Engineered probiotic ameliorates ulcerative colitis by restoring gut microbiota and redox homeostasis

Probiotics are potential treatments for ulcerative colitis (UC), but their efficacy is frequently compromised by gastrointestinal conditions that limit adhesion and activity. Here, we use machine learning and bioinformatics to confirm that patients with UC have decreased prevalence of Lactobacillus genus and increased oxidative stress, which correlate with inflammation severity. Accordingly, we developed a probiotic-based therapeutic that synergistically restores intestinal redox and microbiota homeostasis. Lactobacillus casei (Lac) were induced to form a pericellular film, providing a polysaccharide network for spatially confined crystallization of ultrasmall but highly active selenium dots (Se-Lac). Upon oral administration, the selenium dot-embedded pericellular film efficiently enhanced gastric acid resistance and intestinal mucoadhesion of Lac cells. At the lesion site, the selenium dots scavenged reactive oxygen species, while Lac modulated the gut microbiota. In multiple mouse models and non-human primates, this therapeutic effectively relieved inflammation and reduced colonic damage, thus showing promise as a UC treatment.

Human breast milk isolated lactic acid bacteria: antimicrobial and immunomodulatory activity on the Galleria mellonella burn wound model

Introduction

Managing burn injuries is a challenge in healthcare. Due to the alarming increase in antibiotic resistance, new prophylactic and therapeutic strategies are being sought. This study aimed to evaluate the potential of live Lactic Acid Bacteria for managing burn infections, using Galleria mellonella larvae as an alternative preclinical animal model and comparing the outcomes with a common antibiotic.

Methods

The antimicrobial activity of LAB isolated from human breast milk was assessed in vitro against Pseudomonas aeruginosa ATCC 27853. Additionally, the immunomodulatory effects of LAB were evaluated in vivo using the G. mellonella burn wound infection model.

Results and discussion

In vitro results demonstrated the antimicrobial activity of Lactic Acid Bacteria against P. aeruginosa. In vivo results show that their prophylactic treatment improves, statistically significant, larval survival and modulates the expression of immunity-related genes, Gallerimycin and Relish/NF-κB, strain-dependently. These findings lay the foundation and suggest a promising alternative for burn wound prevention and management, reducing the risk of antibiotic resistance, enhancing immune modulation, and validating the potential G. mellonella as a skin burn wound model.

Predicting the immunomodulatory activity of probiotic lactic acid bacteria using supervised machine learning in a Cornu aspersum snail model

In the process of screening for probiotic strains, there are no clearly established bacterial phenotypic markers which could be used for the prediction of their in vivo mechanism of action. In this work, we demonstrate for the first time that Machine Learning (ML) methods can be used for accurately predicting the in vivo immunomodulatory activity of probiotic strains based on their cell surface phenotypic features using a snail host-microbe interaction model. A broad range of snail gut presumptive probiotics, including 240 new lactic acid bacterial strains (Lactobacillus, Leuconostoc, Lactococcus, and Enterococcus), were isolated and characterized based on their capacity to withstand snails' gastrointestinal defense barriers, such as the pedal mucus, gastric mucus, gastric juices, and acidic pH, in association with their cell surface hydrophobicity, autoaggregation, and biofilm formation ability. The implemented ML pipeline predicted with high accuracy (88 %) strains with a strong capacity to enhance chemotaxis and phagocytic activity of snails' hemolymph cells, while also revealed bacterial autoaggregation and cell surface hydrophobicity as the most important parameters that significantly affect host immune responses. The results show that ML approaches may be useful to derive a predictive understanding of host-probiotic interactions, while also highlighted the use of snails as an efficient animal model for screening presumptive probiotic strains in the light of their interaction with cellular innate immune responses.

The growth-promoting effects of protein hydrolysates and their derived peptides on probiotics: structure-activity relationships, mechanisms and future perspectives

Lactic acid bacteria (LAB) are the main probiotics currently available in the markets and are essential for maintaining gut health. To guarantee probiotic function, it is imperative to boost the culture yield of probiotic organisms, ensure the sufficient viable cells in commercial products, or develop effective prebiotics. Recent studies have shown that protein hydrolysates and their derived peptides promote the proliferation of probiotic in vitro and the abundance of gut flora. This article comprehensively reviews different sources of protein hydrolysates and their derived peptides as growth-promoting factors for probiotics including Lactobacillus, Bifidobacterium, and Saccharomyces. We also provide a preliminary analysis of the characteristics of LAB proteolytic systems focusing on the correlation between their elements and growth-promoting activities. The structure-activity relationship and underlying mechanisms of growth-promoting peptides and their research perspectives are thoroughly discussed. Overall, this review provides valuable insights into growth-promoting protein hydrolysates and their derived peptides for proliferating probiotics in vivo or in vitro, which may inspire researchers to explore new options for industrial probiotics proliferation, dairy products fermentation, and novel prebiotics development in the future.

Intestinal Delivery of Probiotics: Materials, Strategies, and Applications

Probiotics with diverse and crucial properties and functions have attracted broad interest from many researchers, who adopt intestinal delivery of probiotics to modulate the gut microbiota. However, the major problems faced for the therapeutic applications of probiotics are the viability and colonization of probiotics during their processing, oral intake, and subsequent delivery to the gut. The challenges of simple oral delivery (stability, controllability, targeting, etc.) have greatly limited the use of probiotics in clinical therapies. Nanotechnology can endow the probiotics to be delivered to the intestine with improved survival rate and increased resistance to the adverse environment. Additionally, the progress in synthetic biology has created new opportunities for efficiently and purposefully designing and manipulating the probiotics. In this article, a brief overview of the types of probiotics for intestinal delivery, the current progress of different probiotic encapsulation strategies, including the chemical, physical, and genetic strategies and their combinations, and the emerging single-cell encapsulation strategies using nanocoating methods, is presented. The action mechanisms of probiotics that are responsible for eliciting beneficial effects are also briefly discussed. Finally, the therapeutic applications of engineered probiotics are discussed, and the future trends toward developing engineered probiotics with advanced features and improved health benefits are proposed.

Novel Z-DNA binding domains in giant viruses

Z-nucleic acid structures play vital roles in cellular processes and have implications in innate immunity due to their recognition by Zα domains containing proteins (Z-DNA/Z-RNA binding proteins, ZBPs). Although Zα domains have been identified in six proteins, including viral E3L, ORF112, and I73R, as well as, cellular ADAR1, ZBP1, and PKZ, their prevalence across living organisms remains largely unexplored. In this study, we introduce a computational approach to predict Zα domains, leading to the revelation of previously unidentified Zα domain-containing proteins in eukaryotic organisms, including non-metazoan species. Our findings encompass the discovery of new ZBPs in previously unexplored giant viruses, members of the Nucleocytoviricota phylum. Through experimental validation, we confirm the Zα functionality of select proteins, establishing their capability to induce the B-to-Z conversion. Additionally, we identify Zα-like domains within bacterial proteins. While these domains share certain features with Zα domains, they lack the ability to bind to Z-nucleic acids or facilitate the B-to-Z DNA conversion. Our findings significantly expand the ZBP family across a wide spectrum of organisms and raise intriguing questions about the evolutionary origins of Zα-containing proteins. Moreover, our study offers fresh perspectives on the functional significance of Zα domains in virus sensing and innate immunity and opens avenues for exploring hitherto undiscovered functions of ZBPs.

Gut microbiome and metabolome alterations in traditional Chinese medicine damp-heat constitution following treatment with a Chinese patent medicine and lifestyle intervention

BACKGROUND

The gut microbiota is crucial in human health and diseases. Traditional Chinese Medicine Constitution (TCMC) divides people into those with a balanced constitution (Ping-he [PH]) and those with an unbalanced constitution. Dampness-heat constitution (Shi-re [SR]) is a common unbalanced constitution in the Chinese population and is susceptible to diseases. However, unbalanced constitutions can be regulated by Chinese medicine and lifestyle interventions in clinical practice. Ermiao Pill (EMP) is a Chinese medicine known for clearing heat and draining dampness and improving SR. However, the efficacy and mechanism of EMP are unclear.

HYPOTHESIS/PURPOSE

To determine alterations in the gut microbiota and metabolome in SR and any changes after EMP treatment combined with lifestyle intervention.

STUDY DESIGN

Randomized clinical trial.

METHODS

We enrolled 112 healthy SR individuals and evaluated the efficacy of EMP along with lifestyle interventions. We further assessed serum cytokine levels, serum and urinary metabolomes, and the gut microbiota by 16S rRNA gene sequencing analysis before and after the EMP and lifestyle interventions.

RESULTS

107 SR individuals (55 in the intervention group and 52 in the control group) completed the 1-month-intervention and 1-year-follow-up. The intervention group significantly improved their health status within 1 month, with a reduced SR symptom score, and the efficacy lasted to the 1-year follow-up. The control group needed a further 6 months to reduce the SR symptom score. The gut microbiota of PH individuals was more diverse and had significantly higher proportions of many bacterial species than the SR. Microbiota co-occurrence network analysis showed that SR enriches metabolites correlating with microbial community structure, consistent with traits of healthy SR-enriched microbiota.

CONCLUSION

EMP combined with lifestyle intervention produced health benefits in SR individuals. Our study indicates a pivotal role of gut microbiota and metabolome alterations in distinguishing between healthy SR and PH. Furthermore, the study reveals structural changes of gut microbiota and metabolites induced by EMP and lifestyle intervention. The treatment enriched the number of beneficial bacteria, such as Akkermansia muciniphila and Lactobacillus in the gut. Our findings provide a strong indication that several metabolite factors are associated with the gut microbiota. Moreover, the gut microbiome and metabolome might be powerful tools for TCMC diagnosis and personalized therapy.

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.

Catheter-related bloodstream infection caused by Lacticaseibacillus paracasei: A case report and literature review

Catheter-related bloodstream infections (CRBSIs) caused by Lactobacillus spp. and Lacticaseibacillus spp. are rare, and their clinical course and optimal treatment remain uncertain. In this report, we present a 46-year-old male patient who experienced clinically diagnosed Lacticaseibacillus paracasei CRBSI on four separate occasions, despite receiving systemic administration of antibiotics and antimicrobial lock therapy. The patient did not develop L. paracasei bacteremia after catheter removal. This case report furthers our knowledge of CRBSI caused by Lactobacillus and related genera and highlights the need for further research.

Novel method for screening probiotic candidates tolerant to human gastrointestinal stress

Tolerance to human gastrointestinal stressors is crucial for probiotics to exhibit their health benefits; however, there is no standardised method for screening their stress tolerance. In this study, we proposed a novel method for screening probiotic candidates tolerant to human gastrointestinal stress-gastrointestinal tolerance assay and culture (GTA-C) method-using black polyethylene terephthalate (PET) non-woven fabric as a scaffold to modify the specialized cellulose film (SCF) method. The modified SCF method showed excellent pH-based diffusion of medium components, had minimal effect on the growth of Escherichia coli K12, and improved the visibility of the colonies. Analysis of kimchi samples cultured using the SCF and modified SCF methods revealed that the modified method diversified the cultured bacteria. GTA in a simulated human fasting state using the modified SCF method showed that acid stress significantly affected the growth of four bacteria used as probiotics and that tolerance to acid stress may be species-dependent. Screening of probiotics in kimchi samples resulted in the identification of lactic acid bacteria tolerant to human gastrointestinal stress during fasting. Our results indicate that the modified SCF method (GTA-C method) is useful for screening probiotics resistant to the gastrointestinal environment during fasting.

Evaluation of in vitro colonisation and immunomodulation of Lactiplantibacillus plantarumL3 microcapsules after subjected to yoghurt storage

This work aimed to evaluate the in vitro adhesive and immunoregulative effects of water‐in‐oil‐in‐water (W/O/W) microencapsulated Lactiplantibacillus plantarum L3 after subjected to yoghurt stress. The W/O/W microencapsulated L. plantarum L3 was prepared and dropped into fresh milk with commercial starters (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The yoghurt was prepared and stored at 4 °C for 21 days. The effects of yoghurt storage and simulated gastrointestinal treatment on the in vitro adhesive and immunomodulatory activities of L. plantarum L3 were investigated. Results showed that the hydrophobicity, auto‐aggregation and biofilm synthesis ability of L. plantarum L3 were improved after yoghurt storage but in a storage time‐dependent manner. The maximum coaggregation coefficients with S. aureus and E. coli were higher than 20%. L. plantarum L3 increased the viability and phagocytosis of mouse RAW264.7 cells, whereas the secretion of NO and proinflammatory cytokines induced by LPS was significantly reduced. In conclusion, yoghurt was a promising vehicle for delivering W/O/W L. plantarum L3 to the intestinal tract.

Evaluation of Functional Properties of Some Lactic Acid Bacteria Strains for Probiotic Applications in Apiculture

This study evaluates the suitability of three lactic acid bacteria (LAB) strains-Lactiplantibacillus plantarum, Lactobacillus acidophilus, and Apilactobacillus kunkeei-for use as probiotics in apiculture. Given the decline in bee populations due to pathogens and environmental stressors, sustainable alternatives to conventional treatments are necessary. This study aimed to assess the potential of these LAB strains in a probiotic formulation for bees through various in vitro tests, including co-culture interactions, biofilm formation, auto-aggregation, antioxidant activity, antimicrobial activity, antibiotic susceptibility, and resistance to high osmotic concentrations. This study aimed to assess both the individual effects of the strains and their combined effects, referred to as the LAB mix. Results indicated no mutual antagonistic activity among the LAB strains, demonstrating their compatibility with multi-strain probiotic formulations. The LAB strains showed significant survival rates under high osmotic stress and simulated gastrointestinal conditions. The LAB mix displayed enhanced biofilm formation, antioxidant activity, and antimicrobial efficacy against different bacterial strains. These findings suggest that a probiotic formulation containing these LAB strains could be used for a probiotic formulation, offering a promising approach to mitigating the negative effects of pathogens. Future research should focus on in vivo studies to validate the efficacy of these probiotic bacteria in improving bee health.

Synthesis and Isolation of Phenol- and Thiol-Derived Epicatechin Adducts Prepared from Avocado Peel Procyanidins Using Centrifugal Partition Chromatography and the Evaluation of Their Antimicrobial and Antioxidant Activity

Polyphenols from agro-food waste represent a valuable source of bioactive molecules that can be recovered to be used for their functional properties. Another option is to use them as starting material to generate molecules with new and better properties through semi-synthesis. A proanthocyanidin-rich (PACs) extract from avocado peels was used to prepare several semi-synthetic derivatives of epicatechin by acid cleavage in the presence of phenol and thiol nucleophiles. The adducts formed by this reaction were successfully purified using one-step centrifugal partition chromatography (CPC) and identified by chromatographic and spectroscopic methods. The nine derivatives showed a concentration-dependent free radical scavenging activity in the DPPH assay. All compounds were also tested against a panel of pathogenic bacterial strains formed by Listeria monocytogenes (ATCC 7644 and 19115), Staphylococcus aureus (ATCC 9144), Escherichia coli (ATCC 11775 and 25922), and Salmonella enterica (ATCC 13076). In addition, adducts were tested against two no-pathogenic strains, Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A. Overall, thiol-derived adducts displayed antimicrobial properties and, in some specific cases, inhibited biofilm formation, particularly in Listeria monocytogenes (ATCC 7644). Interestingly, phenolic adducts were inactive against all the strains and could not inhibit its biofilm formation. Moreover, depending on the structure, in specific cases, biofilm formation was strongly promoted. These findings contribute to demonstrating that CPC is a powerful tool to isolate new semi-synthetic molecules using avocado peels as starting material for PACc extraction. These compounds represent new lead molecules with antioxidant and antimicrobial activity.

Phenotypic and proteomic differences in biofilm formation of two Lactiplantibacillus plantarum strains in static and dynamic flow environments

Lactiplantibacillus plantarum is a Gram-positive non-motile bacterium capable of producing biofilms that contribute to the colonization of surfaces in a range of different environments. In this study, we compared two strains, WCFS1 and CIP104448, in their ability to produce biofilms in static and dynamic (flow) environments using an in-house designed flow setup. This flow setup enables us to impose a non-uniform flow velocity profile across the well. Biofilm formation occurred at the bottom of the well for both strains, under static and flow conditions, where in the latter condition, CIP104448 also showed increased biofilm formation at the walls of the well in line with the higher hydrophobicity of the cells and the increased initial attachment efficacy compared to WCFS1. Fluorescence and scanning electron microscopy showed open 3D structured biofilms formed under flow conditions, containing live cells and ∼30 % damaged/dead cells for CIP104448, whereas the WCFS1 biofilm showed live cells closely packed together. Comparative proteome analysis revealed minimal changes between planktonic and static biofilm cells of the respective strains suggesting that biofilm formation within 24 h is merely a passive process. Notably, observed proteome changes in WCFS1 and CIP104448 flow biofilm cells indicated similar and unique responses including changes in metabolic activity, redox/electron transfer and cell division proteins for both strains, and myo-inositol production for WCFS1 and oxidative stress response and DNA damage repair for CIP104448 uniquely. Exposure to DNase and protease treatments as well as lethal concentrations of peracetic acid showed highest resistance of flow biofilms. For the latter, CIP104448 flow biofilm even maintained its high disinfectant resistance after dispersal from the bottom and from the walls of the well. Combining all results highlights that L. plantarum biofilm structure and matrix, and physiological state and stress resistance of cells is strain dependent and strongly affected under flow conditions. It is concluded that consideration of effects of flow on biofilm formation is essential to better understand biofilm formation in different settings, including food processing environments.

Antimicrobial Activity, Genetic Relatedness, and Safety Assessment of Potential Probiotic Lactic Acid Bacteria Isolated from a Rearing Tank of Rotifers (Brachionus plicatilis) Used as Live Feed in Fish Larviculture

Aquaculture is a rapidly expanding agri-food industry that faces substantial economic losses due to infectious disease outbreaks, such as bacterial infections. These outbreaks cause disruptions and high mortalities at various stages of the rearing process, especially in the larval stages. Probiotic bacteria are emerging as promising and sustainable alternative or complementary strategies to vaccination and the use of antibiotics in aquaculture. In this study, potential probiotic candidates for larviculture were isolated from a rotifer-rearing tank used as the first live feed for turbot larvae. Two Lacticaseibacillus paracasei and two Lactiplantibacillus plantarum isolates were selected for further characterization due to their wide and strong antimicrobial activity against several ichthyopathogens, both Gram-positive and Gram-negative. An extensive in vitro safety assessment of these four isolates revealed the absence of harmful traits, such as acquired antimicrobial resistance and other virulence factors (i.e., hemolytic and gelatinase activities, bile salt deconjugation, and mucin degradation, as well as PCR detection of biogenic amine production). Moreover, Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) analyses unveiled their genetic relatedness, revealing two divergent clusters within each species. To our knowledge, this work reports for the first time the isolation and characterization of Lactic Acid Bacteria (LAB) with potential use as probiotics in aquaculture from rotifer-rearing tanks, which have the potential to optimize turbot larviculture and to introduce novel microbial management approaches for a sustainable aquaculture.

Resistance role of Lactobacillus sp. and Lactococcus sp. to copper ions in healthy children's intestinal microorganisms

Heavy metal exposure is closely associated with gut microbe function and tolerance. However, intestinal microbe responses in children to different copper ion (Cu2+) concentrations have not yet been clarified. Here, in vitro cultivation systems were established for fecal microbe control and Cu2+-treated groups in healthy children. 16S rDNA high-throughput sequencing, meta-transcriptomics and metabolomics were used here to identify toxicity resistance mechanisms at microbiome levels. The results showed that Lactobacillus sp. and Lactococcus sp. exerted protective effects against Cu2+ toxicity, but these effects were limited by Cu2+ concentration. When the Cu2+ concentration was ≥ 4 mg/L, the abundance of Lactobacillus sp. and Lactococcus sp. significantly decreased, and the pathways of antioxidant activity and detoxification processes were enriched at 2 mg/L Cu2+, and beneficial metabolites accumulated. However, at high concentrations of Cu2+ (≥4 mg/L), the abundance of potential pathogen increased, and was accompanied by a downregulation of genes in metabolism and detoxification pathways, which meant that the balance of gut microbiota was disrupted and toxicity resistance decreased. From these observations, we identified some probiotics that are tolerant to heavy metal Cu2+, and warn that only when the concentration limit of Cu2+ in food is 2 mg/L, then a balanced gut microbiota can be guaranteed in children, thereby providing protection for their health.

Exopolysaccharides and Surface-Layer Proteins Expressed by Biofilm-State Lactiplantibacillus plantarum Y42 Play Crucial Role in Preventing Intestinal Barrier and Immunity Dysfunction of Balb/C Mice Infected by Listeria monocytogenes ATCC 19115

Our previous study showed that Lactiplantibacillus plantarum Y42 in the biofilm state can produce more exopolysaccharides and surface-layer proteins and showed a stronger promoting effect on intestinal barrier function than that in the planktonic state. In this study, oral administration of the live/pasteurized planktonic or biofilm L. plantarum Y42 and its metabolites (exopolysaccharides and surface-layer proteins) increased the expression of Occludin, Claudin-1, ZO-1, and MUC2 in the gut of the Balb/C mice after exposure to Listeria monocytogenes ATCC 19115 and inhibited the activation of the NLRP3 inflammasome pathway, which in turn reduced the levels of inflammatory cytokines IL-1β and IL-18 in the serum of the mice. Furthermore, oral administration of the live/pasteurized planktonic or biofilm L. plantarum Y42 and its metabolites increased the abundance of beneficial bacteria (e.g., Lachnospiraceae_NK4A136_group and Prevotellaceae_UCG-001) while reducing the abundance of harmful bacteria (e.g., norank_f__Muribaculaceae) in the gut of the mice, in line with the increase of short-chain fatty acids and indole derivatives in the feces of the mice. Notably, biofilm L. plantarum Y42 exerted a better preventing effect on the intestinal barrier dysfunction of the Balb/C mice due to the fact that biofilm L. plantarumY42 expressed more exopolysaccharides and surface-layer proteins than the planktonic state. These results provide data support for the use of exopolysaccharides and surface-layer proteins extracted from biofilm-state L. plantarum Y42 as functional food ingredients in preventing intestinal barrier dysfunction.

The role of probiotic therapy on clinical parameters and human immune response in peri-implant diseases: a systematic review and meta-analysis of randomized clinical studies

Background

Peri-implant diseases (peri-implant mucositis and peri-implantitis) are pathologies of an infectious-inflammatory nature of the mucosa around dental implants. Probiotics are microorganisms that regulate host immunomodulation and have shown positive results in the treatment of peri-implant diseases. The objective of the systematic review and meta-analysis was to evaluate the efficacy of probiotics in the treatment of peri-implant oral diseases.

Methods

According to the PRISMA guidelines, the research question was established: Are probiotics able to favorably modify clinical and immunological biomarkers determinants of peri-implant pathologies? and an electronic search of the databases MEDLINE/PubMed, Embase, Cochrane Central, Web of Science, (until December 2023) was performed. Inclusion criteria were established for intervention studies (RCTs), according to the PICOs strategy in subjects with peri-implant pathology (participants), treated with probiotics (intervention) compared to patients with conventional treatment or placebo (control) and evaluating the response to treatment (outcomes). Results- 1723 studies were obtained and 10 were selected. Risk of bias was assessed using the Cochrane Risk of Bias Tool and methodological quality using the Joanna Briggs Institute for RCTs. Two meta-analyses were performed, one to evaluate probiotics in mucositis and one for peri-implantitis. All subgroups were homogeneous (I2 = 0%), except in the analysis of IL-6 in mucositis (I2 = 65%). The overall effect was favorable to the experimental group in both pathologies. The analysis of the studies grouped in peri-implantitis showed a tendency to significance (p=0.09).

Conclusion

The use of probiotics, as basic or complementary treatment of peri-implant diseases, showed a statistically significant trend, but well-designed studies are warranted to validate the efficacy of these products in peri-implant pathologies.

Evaluation of Potential Probiotic Properties and In Vivo Safety of Lactic Acid Bacteria and Yeast Strains Isolated from Traditional Home-Made Kefir

Probiotics are known for their health-promoting resources and are considered as beneficial microorganisms. The current study focuses on the isolation, and on a complete in vitro and in vivo characterization, of yeast and lactic acid bacteria acquired from traditional homemade kefir in order to assess their potentiality as probiotic candidates. In particular, the isolates Pichia kudriavzevii Y1, Lactococcus lactis subsp. hordniae LAB1 and Lactococcus lactis subsp. lactis LAB2 were subjected to in vitro characterization to evaluate their suitability as probiotics. Resistance to acid and bile salts, auto-aggregation, co-aggregation, hydrophobicity, and biofilm production capability were examined, as well as their antioxidant activity. A safety assessment was also conducted to confirm the non-pathogenic nature of the isolates, with hemolysis assay and antibiotic resistance assessment. Moreover, mortality in the invertebrate model Galleria mellonella was evaluated. Current findings showed that P. kudriavzevii exhibited estimable probiotic properties, placing them as promising candidates for functional foods. Both lactic acid bacteria isolated in this work could be classified as potential probiotics with advantageous traits, including antimicrobial activity against enteric pathogens and good adhesion ability on intestinal cells. This study revealed that homemade kefir could be a beneficial origin of different probiotic microorganisms that may enhance health and wellness.

Bioactive Potential of Carrot-Based Products Enriched with Lactobacillus plantarum

The primary goal of this study was to generate different kinds of functional products based on carrots that were supplemented with lactic acid bacteria. The fact that carrots (Daucus carota sp.) rank among the most popular vegetables in our country led to the convergence of the research aim. Their abundance of bioactive compounds, primarily polyphenols, flavonoids, and carotenoids, offers numerous health benefits. Among the obtained products, the freeze-dried carrot powder (FDCP) variation presented the highest concentrations of total carotenoids (TCs) and β-carotene (BC) of 26.977 ± 0.13 mg/g DW and 22.075 ± 0.14 mg/g DW, respectively. The amount of total carotenoids and β-carotene significantly increased with the addition of the selected lactic acid bacteria (LAB) for most of the samples. In addition, a slight increase in the antioxidant activity compared with the control sample for the FDCP variant, with the highest value of 91.74%, was observed in these functional food products. The content of polyphenolic compounds varied from 0.044 to 0.091 mg/g DW, while the content of total flavonoids varied from 0.03 to 0.66 mg/g DW. The processing method had an impact on the population of L. plantarum that survived, as indicated by the viability of bacterial cells in all the analyzed products. The chromatographic analysis through UHPLC-MS/MS further confirmed the abundance of the bioactive compounds and their corresponding derivatives by revealing 19 different compounds. The digestibility study indicated that carotenoid compounds from carrots followed a rather controlled release. The carrot-based products enriched with Lactobacillus plantarum can be considered newly functional developed products based on their high content of biologically active compounds with beneficial effects upon the human body. Furthermore, these types of products could represent innovative products for every related industry such as the food, pharmaceutical, and cosmeceutical industries, thus converging a new strategy to improve the health of consumers or patients.

Protective Effect of Probiotics against Pseudomonas aeruginosa Infection of Human Corneal Epithelial Cells

Probiotic therapy needs consideration as an alternative strategy to prevent and possibly treat corneal infection. This study aimed to assess the preventive effect of Lactobacillus reuteri and Bifidobacterium longum subsp. infantis on reducing the infection of human corneal epithelial (HCE) cells caused by Pseudomonas aeruginosa. The probiotics' preventive effect against infection was evaluated in cell monolayers pretreated with each probiotic 1 h and 24 h prior to P. aeruginosa challenge followed by 1 h and 24 h of growth in combination. Cell adhesion, cytotoxicity, anti-inflammatory, and antinitrosative activities were evaluated. L. reuteri and B. longum adhered to HCE cells, preserved occludin tight junctions' integrity, and increased mucin production on a SkinEthicTM HCE model. Pretreatment with L. reuteri or B. longum significantly protected HCE cells from infection at 24 h, increasing cell viability at 110% (110.51 ± 5.15; p ≤ 0.05) and 137% (137.55 ± 11.97; p ≤ 0.05), respectively. Each probiotic showed anti-inflammatory and antinitrosative activities, reducing TNF-α level (p ≤ 0.001) and NOx amount (p ≤ 0.001) and reestablishing IL-10 level (p ≤ 0.001). In conclusion, this study demonstrated that L. reuteri and B. longum exert protective effects in the context of corneal infection caused by P. aeruginosa by restoring cell viability and modulating inflammatory cytokine release.

Enhance the resistance of probiotics by microencapsulation and biofilm construction based on rhamnogalacturonan I rich pectin

Microcapsules were always used as functional material carriers for targeted delivery and meanwhile offering protection. However, microcapsule wall materials with specific properties were required, which makes the choice of wall material a key factor. In our previous study, a highly branched rhamnogalacturonan I rich (RG-I-rich) pectin was extracted from citrus canning processing water, which showed good gelling properties and binding ability, indicating it could be a potential microcapsule wall material. In the present study, Lactiplantibacillus plantarum GDMCC 1.140 and Lactobacillus rhamnosus were encapsulated by RG-I-rich pectin with embedding efficiencies of about 65 %. The environmental tolerance effect was evaluated under four different environmental stresses. Positive protection results were obtained under all four conditions, especially under H2O2 stress, the survival rate of probiotics embedded in microcapsules was about double that of free probiotics. The storage test showed that the total plate count of L. rhamnosus encapsulated in RG-I-rich pectin microcapsules could still reach 6.38 Log (CFU/mL) at 25 °C for 45 days. Moreover, probiotics embedded in microcapsules with additional incubation to form a biofilm layer inside could further improve the probiotics' activities significantly in the above experiments. In conclusion, RG-I-rich pectin may be a good microcapsule wall material for probiotics protection.

Novel Wild-Type Pediococcus and Lactiplantibacillus Strains as Probiotic Candidates to Manage Obesity-Associated Insulin Resistance

As the food and pharmaceutical industry is continuously seeking new probiotic strains with unique health properties, the aim of the present study was to determine the impact of short-term dietary intervention with novel wild-type strains, isolated from various sources, on high-fat diet (HFD)-induced insulin resistance. Initially, the strains were evaluated in vitro for their ability to survive in simulated gastrointestinal (GI) conditions, for adhesion to Caco-2 cells, for bile salt hydrolase secretion, for cholesterol-lowering and cellular cholesterol-binding ability, and for growth inhibition of food-borne pathogens. In addition, safety criteria were assessed, including hemolytic activity and susceptibility to antibiotics. The in vivo test on insulin resistance showed that mice receiving the HFD supplemented with Pediococcus acidilactici SK (isolated from human feces) or P. acidilactici OLS3-1 strain (isolated from olive fruit) exhibited significantly improved insulin resistance compared to HFD-fed mice or to the normal diet (ND)-fed group.

Rapid discrimination of Lentilactobacillus parabuchneri biofilms via in situ infrared spectroscopy

Microbial contamination in food industry is a source of foodborne illnesses and biofilm-related diseases. In particular, biogenic amines (BAs) accumulated in fermented foods via lactic acid bacterial activity exert toxic effects on human health. Among these, biofilms of histamine-producer Lentilactobacillus parabuchneri strains adherent at food processing equipment surfaces can cause food spoilage and poisoning. Understanding the chain of contamination is closely related to elucidating molecular mechanisms of biofilm formation. In the present study, an innovative approach using integrated chemical sensing technologies is demonstrated to fundamentally understand the temporal behavior of biofilms at the molecular level by combining mid-infrared (MIR) spectroscopy and fluorescence sensing strategies. Using these concepts, the biofilm forming capacity of six cheese-isolated L. parabuchneri strains (IPLA 11151, 11150, 11129, 11125, 11122 and 11117) was examined. The cut-off values for the biofilm production ability of each strain were quantified using crystal violet (CV) assays. Real-time infrared attenuated total reflection spectroscopy (IR-ATR) combined with fluorescence quenching oxygen sensing provides insight into distinct molecular mechanisms for each strain. IR spectra showed significant changes in characteristic bands of amides, lactate, nucleic acids, and extracellular polymeric substances (i.e., lipopolysaccharides, phospholipids, phosphodiester, peptidoglycan, etc.), which are major contributors to biofilm maturation involved in the initial adhesion processes. Chemometric methods including principal component analysis and partial least square-discriminant analysis facilitated the rapid determination and classification of cheese isolated L. parabuchneri strains unambiguously differentiating the IR signatures based on their ability to produce biofilm. All biofilms were morphologically characterized by confocal laser scanning microscopy on relevant industrial equipment surfaces. In summary, this innovative approach combining MIR spectroscopy with luminescence sensing enables real-time insight into the molecular composition and formation of L. parabuchneri biofilms.

Lactobacilli and Klebsiella: Two Opposites in the Fight for Human Health

The problem of antibiotic resistance is currently very acute. Numerous research and development of new antibacterial drugs are being carried out that could help cope with various infectious agents. One of the promising directions for the search for new antibacterial drugs is the search among the probiotic strains present in the human gastrointestinal tract. This review is devoted to characteristics of one of these probiotic strains that have been studied to date: Limosilactobacillus reuteri. The review discusses its properties, synthesis of various compounds, as well as role of this strain in modulating various systems of the human body. The review also examines key characteristics of one of the most harmful among the currently known pathogenic organisms, Klebsiella, which is significantly resistant to antibiotics existing in medical practice, and also poses a great threat of nosocomial infections. Discussion of characteristics of the two strains, which have opposite effects on human health, may help in creation of new effective antibacterial drugs without significant side effects.

Beneficial Effect of Faecal Microbiota Transplantation on Mild, Moderate and Severe Dextran Sodium Sulphate-Induced Ulcerative Colitis in a Pseudo Germ-Free Animal Model

Transplantation of faecal microbiota (FMT) is generally considered a safe therapeutic procedure with few adverse effects. The main factors that limit the spread of the use of FMT therapy for idiopathic inflammatory bowel disease (IBD) are the necessity of minimising the risk of infection and transfer of another disease. Obtaining the animal model of UC (ulcerative colitis) by exposure to DSS (dextran sodium sulphate) depends on many factors that significantly affect the result. Per os intake of DSS with water is individual for each animal and results in the development of a range of various forms of induced UC. For this reason, the aim of our study was to evaluate the modulation and regenerative effects of FMT on the clinical and histopathological responses and the changes in the bowel microenvironment in pseudo germ-free (PGF) mice of the BALB/c line subjected to chemical induction of mild, moderate and serious forms of UC. The goal was to obtain new data related to the safety and effectiveness of FMT that can contribute to its improved and optimised use. The animals with mild and moderate forms of UC subjected to FMT treatment exhibited lower severity of the disease and markedly lower damage to the colon, including reduced clinical and histological disease index and decreased inflammatory response of colon mucosa. However, FMT treatment failed to achieve the expected therapeutic effect in animals with the serious form of UC activity. The results of our study indicated a potential safety risk involving development of bacteraemia and also translocation of non-pathogenic representatives of bowel microbiota associated with FMT treatment of animals with a diagnosed serious form of UC.

Prebiotic Cellulose-Pullulan Matrix as a "Vehicle" for Probiotic Biofilm Delivery to the Host Large Intestine

This study describes the development of a new combined polysaccharide-matrix-based technology for the immobilization of Lactobacillus rhamnosus GG (LGG) bacteria in biofilm form. The new composition allows for delivering the bacteria to the digestive tract in a manner that improves their robustness compared with planktonic cells and released biofilm cells. Granules consisting of a polysaccharide matrix with probiotic biofilms (PMPB) with high cell density (>9 log CFU/g) were obtained by immobilization in the optimized nutrient medium. Successful probiotic loading was confirmed by fluorescence microscopy and scanning electron microscopy. The developed prebiotic polysaccharide matrix significantly enhanced LGG viability under acidic (pH 2.0) and bile salt (0.3%) stress conditions. Enzymatic extract of feces, mimicking colon fluid in terms of cellulase activity, was used to evaluate the intestinal release of probiotics. PMPB granules showed the ability to gradually release a large number of viable LGG cells in the model colon fluid. In vivo, the oral administration of PMPB granules in rats resulted in the successful release of probiotics in the colon environment. The biofilm-forming incubation method of immobilization on a complex polysaccharide matrix tested in this study has shown high efficacy and promising potential for the development of innovative biotechnologies.

Evaluation of the Probiotic Properties of Lacticaseibacillus casei 431® Isolated from Food for Special Medical Purposes§

Research background

Increasing awareness of the importance of nutrition in health promotion and disease prevention has driven to the development of foods for special medical purposes (FSMPs). In this study, the probiotic strain Lacticaseibacillus paracasei ssp. paracasei (Lacticaseibacillus casei 431®) was incorporated into FSMPs to develop an innovative product. The aim was to investigate the influence of the FSMP matrix on the specific probiotic properties of L. casei 431® in vitro.

Experimental approach

A series of in vitro experiments were performed as part of the probiotic approach. After evaluation of antibiotic susceptibility profiles, functional properties such as survival under simulated gastrointestinal tract (GIT) conditions, bile salt deconjugation activities, cholesterol assimilation, antagonistic activity against spoilage bacteria and adhesion to Caco-2 cell line monolayers and extracellular matrix proteins were investigated.

Results and conclusions

The L. casei 431® strain, both the lyophilised strain and the strain isolated from the FSMP matrix, effectively survived the simulated adverse gastrointestinal conditions without significant effects of the food matrix. The effect of the FSMP matrix on the deconjugation activity of the bile salts of L. casei 431® was minimal; however, cholesterol assimilation was increased by 16.4 %. L. casei 431® had antibacterial activity against related lactic acid bacteria regardless of whether it was used in FSMPs or not. Conversely, the probiotic strain isolated from FSMP matrix had significantly higher inhibitory activity against six potential pathogens than the lyophilised culture. The autoaggregation ability of the L. casei 431® cells was not affected by the FSMP matrix. The adhesion of L. casei 431® bacterial cells to the extracellular matrix proteins was reduced after treatment with proteinase K, with the highest adhesion observed to laminin. The adhesion of L. casei 431® reduced the binding of E. coli 3014 by 1.81 log units and the binding of S. Typhimurium FP1 to Caco-2 cell lines by 1.85 log units, suggesting the potential for competitive exclusion of these pathogens.

Novelty and scientific contribution

The results support the positive effect of the FSMP matrix on the specific probiotic properties of L. casei 431®, such as antibacterial activity, bile salt deconjugation and cholesterol assimilation, while the incorporation of this probiotic strain adds functional value to the FSMPs. The synergistic effect achieved by the joint application of L. casei 431® and innovative FSMP matrix contributed to the development of the novel formulation of an improved functional food product with added value.

Draft Genome Sequence and Comparative Genome Analysis Reveal Potential Functional Properties in Lacticaseibacillus paracasei ItalPN16

Nowadays, there is a great interest on rapid and effective methods for initial identification of probiotic bacteria. In this work, potential probiotic features of the lactic acid bacteria strain ItalPN16 isolated from a traditional Brazilian cheese were studied using bioinformatic tools. The complete genome sequence was obtained, and in silico analyses were carried out to identify the strain and its potential probiotic properties. The sequenced genome (3.02 Mb) presented 3126 protein-coding sequences distributed on 244 SEED subsystems, classifying the strain as nomadic lactobacilli. Phylogenetic and ANI analyses allowed to locate the ItalPN16 strain as a member of the Lacticaseibacillus paracasei group, due to the highest number of orthologous genes in common with reference L. paracasei strains (>98%). In silico analyses revealed the presence of CDSs related to microbe-host interactions, such as adhesion proteins and exopolysaccharide biosynthesis genes. The comparative analysis reveals the presence of a strain-specific glycosyl transferases, compared with other three L. paracasei strains and a high level of protein expression (92%) with the probiotic L. paracasei BL29. The results obtained here indicated interesting probiotic features of the strain L. paracasei ItalPN16 that could favor a future application in the food industry.

Limosilactobacillus reuteri DSM 17938 as a probiotic in preterm infants: An updated systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Our previous strain-specific systematic review (SR) showed that Lactobacillus reuteri (LR) DSM 17938 reduces necrotizing enterocolitis (NEC), late-onset sepsis (LOS), and time to full feeds (TFF) in preterm infants. Considering progress in the field over the past 6 years, we aimed to update our SR.

METHODS

SR of randomized controlled trials (RCTs) and non-RCTs was conducted. MEDLINE, Embase, Emcare, Cochrane CENTRAL, and gray literature were searched in June 2023. Primary outcomes were TFF, NEC stage ≥II, LOS, and all-cause mortality. Meta-analysis was performed using random-effects model. Certainty of evidence (CoE) was summarized using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines. Trial sequential analysis (TSA) was applied for outcome of NEC in RCTs.

RESULTS

Twelve RCTs (n = 2284) and four non-RCTs (n = 1616) were included. Six RCTs and three non-RCTs were new. Meta-analysis of RCTs showed LR significantly reduced TFF (mean difference, -2.70 [95% CI, -4.90 to -1.31] days; P = 0.0001), NEC stage ≥II (risk ratio [RR], 0.57 [95% CI, 0.37-0.87]; P = 0.009; eight RCTs), and LOS (RR, 0.72 [95% CI, 0.54-0.97]; P = 0.03); but not mortality (RR, 0.76 [95% CI, 0.54-1.06]; P = 0.10). TSA showed diversity-adjusted required information size (DARIS) as 3624 for NEC. Overall CoE was "very low." Meta-analysis of non-RCTs showed LR reduced NEC (odds ratio, 0.34 [95% CI, 0.15-0.77]; P = 0.01) but not LOS. LR had no adverse effects.

CONCLUSIONS

Very low CoE suggests that LR DSM 17938 may reduce NEC and LOS and shorten TFF in preterm infants. Additional RCTs are required to confirm our findings.

Synbiotic formulations with microbial biofilm, animal derived (casein, collagen, chitosan) and plant derived (starch, cellulose, alginate) prebiotic polymers: A review

The need for a broader range of probiotics, prebiotics, and synbiotics to improve the activity and functioning of gut microbiota has led to the development of new nutraceuticals formulations. These techniques majorly depend on the type of the concerned food, inclusive factors i.e. application of biotic components, probiotics, and synbiotics along with the type of encapsulation involved. For improvisation of the oral transfer mode of synbiotics delivery within the intestine along with viability, efficacy, and stability co-encapsulation is required. The present study explores encapsulation materials, probiotics and prebiotics in the form of synbiotics. The emphasis was given to the selection and usage of probiotic delivery matrix or prebiotic polymers, which primarily include animal derived (gelatine, casein, collagen, chitosan) and plant derived (starch, cellulose, pectin, alginate) materials. Beside this, the role of microbial polymers and biofilms (exopolysaccharides, extracellular polymeric substances) has also been discussed in the formation of probiotic functional foods. In this instance, the microbial biofilm is also used as suitable polymeric compound for encapsulation providing stability, viability, and efficacy. Thus, the review highlights the utilization of diverse prebiotic polymers in synbiotic formulations, along with microbial biofilms, which hold great potential for enhancing gut microbiota activity and improving overall health.

Imbalance of Vaginal Microbiota and Immunity: Two Main Accomplices of Cervical Cancer in Chinese Women

Objective

To explore the correlation of female vaginal microbiota and immune factors with cervical cancer.

Methods

The distribution pattern difference of vaginal microbiota of four groups of women (cervical cancer, HPV-positive CIN, HPV-positive non-CIN, and HPV-negative groups) were compared by microbial 16S rDNA sequencing. The protein chip was used to detect the composition and changes of the immune factors in the four groups.

Results

Alpha diversity analysis demonstrated that the diversity of the vaginal microbiota was increased as the disease develops. Among those bacteria abundant in the vaginal microbiota, Lactobacillus, Prevotella, and Gardnerella dominate at the genus level of vaginal flora. Compared with the HPV-negative group, the differentially dominant bacteria, such as Prevotella, Ralstonia, Gardnerella and Sneathia, are enriched in the cervical cancer group. Likewise, Gardnerella, Prevotella, and Sneathia are more in the HPV-positive CIN group, while Gardnerella and Prevotella in the HPV-positive non-CIN group, respectively. In contrast, Lactobacillus and Atopobium are dominant in the HPV-negative group (LDA>4log10). The concentration of inflammatory immune factors IP-10 and VEGF-A were increased in the cervical cancer group (P < 0.05), compared with other groups.

Conclusion

The occurrence of cervical cancer is related to an increase of vaginal microbiota diversity and up-regulation of inflammatory immune factor proteins. The abundance of Lactobacillus was decreased while the one of Prevotella and Gardnerella were increased in the cervical cancer group, compared with other three groups. Moreover, the IP-10 and VEGF-A were also increased in the cervical cancer group. Thus, evaluation of changes in the vaginal microbiota and these two immune factor levels might be a potential non-invasive and simple method to predict cervical cancer. Furthermore, it is significant to adjust and restore the balance of vaginal microbiota and maintain normal immune function in preventing and treating cervical cancer.

Development and Characterization of Lactobacillus rhamnosus-Containing Bioprints for Application to Catheter-Associated Urinary Tract Infections

Catheter-associated urinary tract infections (CAUTI) are a significant healthcare burden affecting millions of patients annually. CAUTI are characterized by infection of the bladder and pathogen colonization of the catheter surface, making them especially difficult to treat. Various catheter modifications have been employed to reduce pathogen colonization, including infusion of antibiotics and antimicrobial compounds, altering the surface architecture of the catheter, or coating it with nonpathogenic bacteria. Lactobacilli probiotics offer promise for a "bacterial interference" approach because they not only compete for adhesion to the catheter surface but also produce and secrete antimicrobial compounds effective against uropathogens. Three-dimensional (3D) bioprinting has enabled fabrication of well-defined, cell-laden architectures with tailored release of active agents, thereby offering a novel means for sustained probiotic delivery. Silicone has shown to be a promising biomaterial for catheter applications due to mechanical strength, biocompatibility, and its ability to mitigate encrustation on the catheter. Additionally, silicone, as a bioink, provides an optimum matrix for bioprinting lactobacilli. This study formulates and characterizes novel 3D-bioprinted Lactobacillus rhamnosus (L. rhamnosus)-containing silicone scaffolds for future urinary tract catheterization applications. Weight-to-weight (w/w) ratio of silicone/L. rhamnosus was bioprinted and cured with relative catheter dimensions in diameter. Scaffolds were analyzed in vitro for mechanical integrity, recovery of L. rhamnosus, antimicrobial production, and antibacterial effect against uropathogenic Escherichia coli, the leading cause of CAUTI. The results show that L. rhamnosus-containing scaffolds are capable of sustained recovery of live bacteria over 14 days, with sustained production of lactic acid and hydrogen peroxide. Through the use of 3D bioprinting, this study presents a potential alternative strategy to incorporate probiotics into urinary catheters, with the ultimate goal of preventing and treating CAUTI.

Microbial Biofilm: A Review on Formation, Infection, Antibiotic Resistance, Control Measures, and Innovative Treatment

Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.

Preparation of milk-based probiotic lactic acid bacteria biofilms: A new generation of probiotics

Biofilm is considered as a community of microorganisms in which cells adhere to each other on surfaces in a self-produced matrix of extracellular polymer compounds. In recent years, efforts to use the beneficial aspects of biofilm in probiotic research have intensified. In this study, probiotic biofilms of Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus were manufactured using milk and transferred to yogurt in whole and pulverized forms to test in real food conditions. Survival was assessed during 21 days of storage time as well as gastrointestinal conditions. The results indicated that Lp. plantarum and Lc. rhamnosus can form a very desirable and strong biofilm that can have a good protective effect on the survival of these bacteria in probiotic yogurt during processing, storage, and gastrointestinal conditions, in a way that, after 120 min of treatment in high acidic gastrointestinal conditions (pH 2.0), the survival rate decreased by only 0.5 and 1.1 log CFU/ml. Probiotic biofilm can be used as a natural way of utilizing bacteria in biotechnology and fermentation, which is an excellent way to increase the utility of probiotics.

Functional properties of lactic acid bacteria isolated from Tilapia (Oreochromis niloticus) in Ivory Coast

BACKGROUND

Probiotics have recently been applied in aquaculture as eco-friendly alternatives to antibiotics to improve fish health, simultaneously with the increase of production parameters. The present study aimed to investigate the functional potential of lactic acid bacteria (LAB) isolated from the gut of Tilapia (Oreochromis niloticus) originating from the aquaculture farm of Oceanologic Research Center in Ivory Coast.

RESULTS

Twelve LAB strains were identified by 16 S rDNA gene sequence homology analysis belonging to two genera Pediococcus (P. acidilactici and P. pentosaceus) and Lactobacillus (L. plantarum) with a predominance of P. acidilactici. Several aspects including functional, storage, and safety characteristics were taken into consideration in the selection process of the native LAB isolates as potential probiotics. All LAB isolates showed high antagonistic activity against bacterial pathogens like Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus. In addition, the LAB isolates exhibited different degrees of cell surface hydrophobicity in the presence of hexane, xylene, and chloroform as solvents and a good ability to form biofilm. The strong antioxidant activity expressed through the DPPH scavenging capacity of LAB intact cells and their cell-free supernatants was detected. LAB strains survived between 34.18% and 49.9% when exposed to low pH (1.5) and pepsin for 3 h. In presence of 0.3% bile salts, the growth rate ranged from 0.92 to 21.46%. Antibiotic susceptibility pattern of LAB isolates showed sensitivity or intermediate resistance to amoxicillin, cephalothin, chloramphenicol, imipenem, kanamycin, penicillin, rifampicin, streptomycin, tetracycline and resistance to oxacillin, gentamicin, and ciprofloxacin. No significant difference in antibiotic susceptibility pattern was observed between P. acidilactici and P. pentosaceus strains. The non-hemolytic activity was detected. Following the analysis of the enzyme profile, the ability of LAB isolates to produce either lipase or β-galactosidase or both enzymes was highlighted. Furthermore, the efficacy of cryoprotective agents was proved to be isolate-dependent, with LAB isolates having a high affinity for D-sorbitol and sucrose.

CONCLUSION

The explored LAB strains inhibited the growth of pathogens and survived after exposure to simulated gastrointestinal tract conditions. The safety and preservative properties are desirable attributes of these new probiotic strains hence recommended for future food and feed applications.

Probiotic candidates for controlling Paenibacillus larvae, a causative agent of American foulbrood disease in honey bee

BACKGROUND

American foulbrood (AFB) disease caused by Paenibacillus larvae is dangerous, and threatens beekeeping. The eco-friendly treatment method using probiotics is expected to be the prospective method for controlling this pathogen in honey bees. Therefore, this study investigated the bacterial species that have antimicrobial activity against P. larvae.

RESULTS

Overall, 67 strains of the gut microbiome were isolated and identified in three phyla; the isolates had the following prevalence rates: Firmicutes 41/67 (61.19%), Actinobacteria 24/67 (35.82%), and Proteobacteria 2/67 (2.99%). Antimicrobial properties against P. larvae on agar plates were seen in 20 isolates of the genus Lactobacillus, Firmicutes phylum. Six representative strains from each species (L. apis HSY8_B25, L. panisapium PKH2_L3, L. melliventris HSY3_B5, L. kimbladii AHS3_B36, L. kullabergensis OMG2_B25, and L. mellis OMG2_B33) with the largest inhibition zones on agar plates were selected for in vitro larvae rearing challenges. The results showed that three isolates (L. apis HSY8_B25, L. panisapium PKH2_L3, and L. melliventris HSY3_B5) had the potential to be probiotic candidates with the properties of safety to larvae, inhibition against P. larvae in infected larvae, and high adhesion ability.

CONCLUSIONS

Overall, 20 strains of the genus Lactobacillus with antimicrobial properties against P. larvae were identified in this study. Three representative strains from different species (L. apis HSY8_B25, L. panisapium PKH2_L3, and L. melliventris HSY3_B5) were evaluated to be potential probiotic candidates and were selected for probiotic development for the prevention of AFB. Importantly, the species L. panisapium isolated from larvae was identified with antimicrobial activity for the first time in this study.

Probiotic Weissella cibaria displays antibacterial and anti-biofilm effect against cavity-causing Streptococcus mutans

Streptococcus mutans is a significant contributor to dental caries and causes functional and aesthetic discomfort. Weissella cibaria strains were isolated from kimchi, and their functional properties were determined. In this study, the antibacterial and antibiofilm effects of four W. cibaria strains (D29, D30, D31, and B22) were evaluated against three S. mutans strains using culture fluid and cell-free supernatants. The results showed that W. cibaria reduced the exopolysaccharides production and auto-aggregation, increased co-aggregation, and downregulated virulence factors, leading to the inhibition of bacterial growth and biofilm formation. These findings were confirmed using scanning electron microscopy and confocal laser scanning microscopy. These results indicate that oral health can be potentially improved by W. cibaria.