Isolation and Characterization of Lactic Acid Bacteria With Probiotic Attributes From Different Parts of the Gastrointestinal Tract of Free-living Wild Boars in Hungary. - Related Documents




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603401.0000Isolation and Characterization of Lactic Acid Bacteria With Probiotic Attributes From Different Parts of the Gastrointestinal Tract of Free-living Wild Boars in Hungary. Lactic acid bacteria (LAB) in the microbiota play an important role in human and animal health and, when used as probiotics, can contribute to an increased growth performance in livestock management. Animals living in their native habitat can serve as natural sources of microorganisms, so isolation of LAB strains from wild boars could provide the opportunity to develop effective probiotics to improve production in swine industry. In this study, the probiotic potential of 56 LAB isolates, originated from the ileum, colon, caecum and faeces of 5 wild boars, were assessed in vitro in details. Their taxonomic identity at species level and their antibacterial activity against four representative strains of potentially pathogenic bacteria were determined. The ability to tolerate low pH and bile salt, antibiotic susceptibility, bile salt hydrolase activity and lack of hemolysis were tested. Draft genome sequences of ten Limosilactobacillus mucosae and three Leuconostoc suionicum strains were determined. Bioinformatic analysis excluded the presence of any known acquired antibiotic resistance genes. Three genes, encoding mesentericin B105 and two different bacteriocin-IIc class proteins, as well as two genes with possible involvement in mesentericin secretion (mesE) and transport (mesD) were identified in two L. suionicum strains. Lam29 protein, a component of an ABC transporter with proved function as mucin- and epithelial cell-adhesion factor, and a bile salt hydrolase gene were found in all ten L. mucosae genomes. Comprehensive reconsideration of all data helps to select candidate strains to assess their probiotic potential further in animal experiments.202437353593
607010.9996Probiotic bacteria of wild boar origin intended for piglets - An in vitro study. Using probiotics represents a potential solution to post-weaning diarrheal diseases in piglets on commercial farms. The gastrointestinal tract of wild boars serves as a promising reservoir of novel lactic acid bacteria with suitable probiotic characteristics. In this study, we isolated eight bacterial strains from the intestinal content of wild boars identified as representatives of the species Bifidobacterium apri, Lactobacillus amylovorus, and Ligilactobacillus salivarius. These isolates underwent in vitro analysis and characterisation to assess their biological safety and probiotic properties. Analysis of their full genome sequences revealed the absence of horizontally transferrable genes for antibiotic resistance. However, seven out of eight isolates harboured genes encoding various types of bacteriocins in their genomes, and bacteriocin production was further confirmed by mass spectrometry analysis. Most of the tested strains demonstrated the ability to inhibit the growth of selected pathogenic bacteria, produce exopolysaccharides, and stimulate the expression of interleukin-10 in porcine macrophages. These characteristics deem the isolates characterised in this study as potential candidates for use as probiotics for piglets during the post-weaning period.202439296628
846420.9996Comparative genomics of 40 Weissella paramesenteroides strains. Weissella strains are often detected in spontaneously fermented foods. Because of their abilities to produce lactic acid and functional exopolysaccharides as well as their probiotic traits, Weissella spp. improve not only the sensorial properties but also nutritional values of the fermented food products. However, some Weissella species have been associated with human and animal diseases. In the era of vast genomic sequencing, new genomic/genome data are becoming available to the public on daily pace. Detailed genomic analyses are due to provide a full understanding of individual Weissella species. In this study, the genomes of six Weissella paramesenteroides strains were de novo sequenced. The genomes of 42 W. paramesenteroides strains were compared to discover their metabolic and functional potentials in food fermentation. Comparative genomics and metabolic pathway reconstructions revealed that W. paramesenteroides is a compact group of heterofermentative bacteria with good capacity of producing secondary metabolites and vitamin Bs. Since the strains rarely harbored plasmid DNA, they did not commonly possess the genes associated with bacteriocin production. All 42 strains were shown to bear vanT gene from the glycopeptide resistance gene cluster vanG. Yet none of the strains carried virulence genes.202337065164
604430.9996Phenotypic and Genetic Characterization and Production Abilities of Lacticaseibacillus rhamnosus Strain 484-A New Probiotic Strain Isolated From Human Breast Milk. Recent studies suggest that human breast milk (HBM) is a promising source of probiotic bacteria with potential applications in both medicine and the food industry. Probiotic bacteria, particularly species of the genus Lactobacillus, are classified as lactic acid bacteria (LAB). However, probiotic properties are strain-specific, as not all Lactobacillus strains exhibit health benefits or inhibit pathogens. This study evaluated the probiotic potential of a newly isolated strain, Lacticaseibacillus rhamnosus strain 484, derived from human milk. Phenotypic and genomic analyses were performed, with L. rhamnosus 1.0320 serving as a reference genome. We focused on strain safety for human use and potential health benefits. Strain 484 underwent probiotic characterization and demonstrated strong auto- and co-aggregation abilities, contributing to effective pathogenic bacteria inhibition. The strain also showed bile tolerance, antibiotic sensitivity, and lacked hemolytic and catalase activity, indicating safety and suitability profiles for oral administration. Its resistance to low pH and bile salts indicated survival during gastrointestinal transit and intestinal colonization. Notably, cell surface hydrophobicity (CSH) exceeded that of the well-known L. rhamnosus GG strain, potentially enhancing adhesion to intestinal epithelial cells. Genomic analysis confirmed no antibiotic resistance genes (ARGs) and plasmids, suggesting genetic stability. Overall, L. rhamnosus 484 appears to be a safe and promising probiotic candidate with potential applications in both medical and food-related fields, particularly for oral use in preventing and controlling common pathogens.202541019172
607140.9996Functional properties of novel protective lactic acid bacteria and application in raw chicken meat against Listeria monocytogenes and Salmonella enteritidis. In this study 635 lactic acid bacteria of food origin were evaluated for their potential application as protective cultures in foods. A stepwise selection method was used to obtain the most appropriate strains for application as protective cultures in chicken meat. Specifically, all strains were examined for antimicrobial activity against various Gram positive and Gram negative pathogenic and spoilage bacteria. Strains exhibiting anti-bacterial activity were subsequently examined for survival in simulated food processing and gastrointestinal tract conditions, such as high temperatures, low pH, starvation and the presence of NaCl and bile salts. Selected strains where then examined for basic safety properties such as antibiotic resistance and haemolytic potential, while their antimicrobial activity was further investigated by PCR screening for possession of known bacteriocin genes. Two chosen strains were then applied on raw chicken meat to evaluate their protective ability against two common food pathogens, Listeria monocytogenes and Salmonella enteritidis, but also to identify potential spoilage effects by the application of the protective cultures on the food matrix. Antimicrobial activity in vitro was evident against Gram positive indicators, mainly Listeria and Brochothrix spp., while no antibacterial activity was obtained against any of the Gram negative bacteria tested. The antimicrobial activity was of a proteinaceous nature while strains with anti-listerial activity were found to possess one or more bacteriocin genes, mainly enterocins. Strains generally exhibited sensitivity to pH 2.0, but good survival at 45 degrees C, in the presence of bile salts and NaCl as well as during starvation, while variable survival rates were obtained at 55 degrees C. None of the strains was found to be haemolytic while variable antibiotic resistance profiles were obtained. Finally, when the selected strains Enterococcus faecium PCD71 and Lactobacillus fermentum ACA-DC179 were applied as protective cultures in chicken meat against L. monocytogenes and S. enteritidis respectively, a significantly reduced growth of these pathogenic bacteria was observed. In addition, these two strains did not appear to have any detrimental effect on biochemical parameters related to spoilage of the chicken meat.200919249112
607250.9995Bad to the bone? - Genomic analysis of Enterococcus isolates from diverse environments reveals that most are safe and display potential as food fermentation microorganisms. Enterococci comprise a group of lactic acid bacteria (LAB) with considerable potential to serve as food fermentation microorganisms. Unfortunately, enterococci have received a lot of negative attention, due to the occurrence of pathogenic and multidrug resistant strains. In this study, we used genomics to select safe candidates among the forty-four studied enterococcal isolates. The genomes of the forty-four strains were fully sequenced and assessed for presence of virulence and antibiotic resistance genes. Nineteen isolates belonging to the species Enterococcus lactis, Enterococcus faecium, Enterococcus durans, and Enterococcus thailandicus, were deemed safe from the genome analysis. The presence of secondary metabolite gene clusters for bacteriocins was assessed, and twelve candidates were found to secrete antimicrobial compounds effective against Listeria monocytogenes isolated from cheese and Staphylococcus aureus. Physiological characterization revealed nineteen industrial potentials; all strains grew well at 42 °C and acidified 1.5 hours faster than their mesophilic counterpart Lactococcus lactis, with which they share metabolism and flavor forming ability. We conclude that a large fraction of the examined enterococci were safe and could serve as excellent food fermentation microorganisms with inherent bioprotective abilities.202438552381
603660.9995Comprehensive Phenotypic Characterization and Genomic Analysis Unveil the Probiotic Potential of Bacillus velezensis K12. Bacillus spp. have emerged as pivotal sources of probiotic preparations, garnering considerable attention in recent years owing to their vigorous bacteriostatic activity and antimicrobial resistance. This study aimed to investigate these probiotic characteristics in depth and verify the safety of Bacillus velezensis K12, a strain isolated from broiler intestine. The K12 strain was identified as Bacillus velezensis based on its morphology and 16S rDNA sequence homology analysis. Subsequently, B. velezensis K12 was evaluated for acid resistance, bile salt resistance, gastrointestinal tolerance, drug sensitivity, and antimicrobial activity. Additionally, whole-genome sequencing technology was employed to dissect its genomic components further, aiming to explore its potential applications as a probiotic strain. B. velezensis K12 was sensitive to six antibiotics and had acid tolerance. Furthermore, it showed potent antimicrobial activity against a wide range of pathogenic bacteria, including Escherichia coli (E. coli), Staphylococcus aureus, Salmonella, Clostridium perfringens, Bacillus cereus, and Vibrio parahaemolyticus. The complete genome sequencing of B. velezensis K12 revealed a genomic length of 3,973,105 base pairs containing 4123 coding genes, among which 3973 genes were functionally annotated. The genomic analysis identified genes associated with acid and bile tolerance, adhesion, antioxidants, and secondary metabolite production, whereas no functional genes related to enterotoxins or transferable antibiotic resistance were detected, thereby confirming the probiotic properties of B. velezensis K12. B. velezensis K12 exhibits broad-spectrum bacteriostatic activity and in vitro safety, positioning it as a potential candidate strain for developing probiotic Bacillus preparations.202540150327
838270.9995Transcriptional and Functional Analysis of Bifidobacterium animalis subsp. lactis Exposure to Tetracycline. Commercial probiotic bacteria must be tested for acquired antibiotic resistance elements to avoid potential transfer to pathogens. The European Food Safety Authority recommends testing resistance using microdilution culture techniques previously used to establish inhibitory thresholds for the Bifidobacterium genus. Many Bifidobacterium animalis subsp. lactis strains exhibit increased resistance to tetracycline, historically attributed to the ribosomal protection gene tet(W). However, some strains that harbor genetically identical tet(W) genes show various inhibition levels, suggesting that other genetic elements also contribute to observed differences. Here, we adapted several molecular assays to confirm the inhibition of B. animalis subsp. lactis strains Bl-04 and HN019 and employed RNA sequencing to assess the transcriptional differences related to genomic polymorphisms. We detected specific stress responses to the antibiotic by correlating ATP concentration to number of viable genome copies from droplet digital PCR and found that the bacteria were still metabolically active in high drug concentrations. Transcriptional analyses revealed that several polymorphic regions, particularly a novel multidrug efflux transporter, were differentially expressed between the strains in each experimental condition, likely having phenotypic effects. We also found that the tet(W) gene was upregulated only during subinhibitory tetracycline concentrations, while two novel tetracycline resistance genes were upregulated at high concentrations. Furthermore, many genes involved in amino acid metabolism and transporter function were upregulated, while genes for complex carbohydrate utilization, protein metabolism, and clustered regularly interspaced short palindromic repeat(s) (CRISPR)-Cas systems were downregulated. These results provide high-throughput means for assessing antibiotic resistances of two highly related probiotic strains and determine the genetic network that contributes to the global tetracycline response.IMPORTANCEBifidobacterium animalis subsp. lactis is widely used in human food and dietary supplements. Although well documented to be safe, B. animalis subsp. lactis strains must not contain transferable antibiotic resistance elements. Many B. animalis subsp. lactis strains have different resistance measurements despite being genetically similar, and the reasons for this are not well understood. In the current study, we sought to examine how genomic differences between two closely related industrial B. animalis subsp. lactis strains contribute to different resistance levels. This will lead to a better understanding of resistance, identify future targets for analysis of transferability, and expand our understanding of tetracycline resistance in bacteria.201830266728
839180.9995The Analysis of Field Strains Isolated From Food, Animal and Clinical Sources Uncovers Natural Mutations in Listeria monocytogenes Nisin Resistance Genes. Nisin is a commonly used bacteriocin for controlling spoilage and pathogenic bacteria in food products. Strains possessing high natural nisin resistance that reduce or increase the potency of this bacteriocin against Listeria monocytogenes have been described. Our study sought to gather more insights into nisin resistance mechanisms in natural L. monocytogenes populations by examining a collection of 356 field strains that were isolated from different foods, food production environments, animals and human infections. A growth curve analysis-based approach was used to access nisin inhibition levels and assign the L. monocytogenes strains into three nisin response phenotypic categories; resistant (66%), intermediate (26%), and sensitive (8%). Using this categorization isolation source, serotype, genetic lineage, clonal complex (CC) and strain-dependent natural variation in nisin phenotypic resistance among L. monocytogenes field strains was revealed. Whole genome sequence analysis and comparison of high nisin resistant and sensitive strains led to the identification of new naturally occurring mutations in nisin response genes associated with increased nisin resistance and sensitivity in this bacterium. Increased nisin resistance was detected in strains harboring RsbU(G77S) and PBPB3(V240F) amino acid substitution mutations, which also showed increased detergent stress resistance as well as increased virulence in a zebra fish infection model. On the other hand, increased natural nisin sensitivity was detected among strains with mutations in sigB, vir, and dlt operons that also showed increased lysozyme sensitivity and lower virulence. Overall, our study identified naturally selected mutations involving pbpB3 (lm0441) as well as sigB, vir, and dlt operon genes that are associated with intrinsic nisin resistance in L. monocytogenes field strains recovered from various food and human associated sources. Finally, we show that combining growth parameter-based phenotypic analysis and genome sequencing is an effective approach that can be useful for the identification of novel nisin response associated genetic variants among L. monocytogenes field strains.202033123101
846790.9995The Impacts of Lactiplantibacillus plantarum on the Functional Properties of Fermented Foods: A Review of Current Knowledge. One of the most varied species of lactic acid bacteria is Lactiplantibacillus plantarum (Lb. plantarum), formerly known as Lactobacillus plantarum. It is one of the most common species of bacteria found in foods, probiotics, dairy products, and beverages. Studies related to genomic mapping and gene locations of Lb. plantarum have shown the novel findings of its new strains along with their non-pathogenic or non-antibiotic resistance genes. Safe strains obtained with new technologies are a pioneer in the development of new probiotics and starter cultures for the food industry. However, the safety of Lb. plantarum strains and their bacteriocins should also be confirmed with in vivo studies before being employed as food additives. Many of the Lb. plantarum strains and their bacteriocins are generally safe in terms of antibiotic resistance genes. Thus, they provide a great opportunity for improving the nutritional composition, shelf life, antioxidant activity, flavour properties and antimicrobial activities in the food industry. Moreover, since some Lb. plantarum strains have the ability to reduce undesirable compounds such as aflatoxins, they have potential use in maintaining food safety and preventing food spoilage. This review emphasizes the impacts of Lb. plantarum strains on fermented foods, along with novel approaches to their genomic mapping and safety aspects.202235456875
6033100.9995Antibacterial Activity of Lactobacillus Strains Isolated from Mongolian Yogurt against Gardnerella vaginalis. Worldwide interest in the use of functional foods containing probiotic bacteria such as Lactobacillus and Bifidobacterium for health promotion and disease prevention has increased significantly. Probiotics have demonstrated beneficial properties including strengthening the body's natural defense system, inhibiting the growth of pathogenic bacteria, and regulating mental activity, but their effects on the human vagina have not been fully elucidated. The primary purpose of our study was to isolate Lactobacillus strains from old yogurt, a traditional dairy product, and investigate their probiotic potential with respect to the human vaginal system. Four Lactobacillus plantarum (L. plantarum) strains, named ZX1, ZX2, ZX27, and ZX69, were isolated from the yogurt samples. Simultaneously, we used a commercial Lactobacillus strain (Lactobacillus delbrueckii DM8909) as a control strain. We tested the antimicrobial activity of Lactobacillus isolates against Escherichia coli and Gardnerella vaginalis by agar spot and well diffusion tests. Then, we tested the antibiotic susceptibility of the 5 strains by using the minimal inhibitory concentration method. We attempted to detect possible bacteriocin genes by PCR sequencing technique. Using a chemically defined medium simulating genital tract secretions, we found that the selected Lactobacillus strains could alter the expression of known virulence genes in Gardnerella vaginalis. Bacteriocins derived from these isolated strains had potent antibacterial activity against G. vaginalis and E. coli, with the most effective activity observed in the case of ZX27. In addition, all strains including the L. delbrueckii DM8909 were positive for the presence of the plantaricin cluster of genes described in L. plantarum C11. The tested stains possessed the pln gene indicating that one of the antibacterial agents was plantaricin. We assume that the production of antimicrobial substances such as bacteriocins induce G. vaginalis to upregulate antimicrobial resistance genes. The new isolated strains have bacteriocin-related genes and can change the antimicrobial resistance gene transcription of G. vaginalis.202032382546
6074110.9995Beneficial properties of lactic acid bacteria naturally present in dairy production. BACKGROUND: Consumers are increasingly demanding for natural and beneficial foods, in order to improve their health and well-being. Probiotics play an important role in such demand, and dairy foods are commonly used as vehicles for such bacteria, represented predominantly by lactic acid bacteria. Due to consumers demand, food industry is constantly looking for novel bacterial strains, leading to studies that aims the isolation and characterization of their beneficial features. This study aimed to characterize the naturally occurring lactic acid bacteria obtained from a dairy environment, in order to assess their potential use as probiotics. RESULTS: Preliminary screening and PCR analysis, based on 16S rRNA sequencing, were applied to select and identify 15 LAB strains from the genera Lactobacillus (n = 11), Pediococcus (n = 2) and Weissella (n = 2). All strains showed resistance to low pH and the evaluated bile salt concentrations in vitro. The API ZYM test characterized the enzymatic activity of the strains, and a high β-galactosidase activity was observed in 13 strains. All strains presented resistance to simulated gastric (3 h) and intestinal (4 h) conditions in vitro, the ability to auto- and co-aggregate with indicator microorganisms and a high cell surface hydrophobicity. Most of the strains were positive for map and EFTu beneficial genes. All strains exhibited strong deconjugation of bile salts in vitro and all assimilated lactose. CONCLUSIONS: The phenotypes exhibited in vitro and the presence of beneficial genes revealed the beneficial potential of the studied strains, demanding further analyses in a food matrix and in vivo to allow the development of a functional product, with health-related properties.201830567551
6073120.9995Molecular Assessment and Validation of the Selected Enterococcal Strains as Probiotics. Probiotics are live microorganisms which confer health benefits to the host. Lactic acid bacteria (LAB) are used as probiotics since decades. Enterococci being the member of LAB have proven probiotic strains; therefore, this study was aimed at finding out the potential probiotic candidates from the pool of locally isolated strains. For initial screening, one hundred and twenty-two strains were selected and subjected to different confirmatory and phenotypic tests to choose the best strains that have potential probiotic criteria, i.e., no potential virulence traits, antibiotic resistance, and having tolerance properties. Keeping this criterion, only eleven strains (n = 11) were selected for further assessment. All virulence traits such as production of hemolysin, gelatinase, biofilm, and DNase were performed and not found in the tested strains. The molecular assessment indicates the presence of few virulence-associated genes in Enterococcus faecalis strains with variable frequency. The phenotypic and genotypic assessments of antibiotic resistance profile indicate that the selected strain was susceptible to ten commonly used antibiotics, and there were no transferrable antibiotic resistance genes. The presence of CRISPR-Cas genes also confirmed the absence of antibiotic resistance genes. Various enterocin-producing genes like EntP, EntB, EntA, and EntQ were also identified in the selected strains which make them promising probiotic lead strains. Different tolerance assays like acid, NaCl, and gastric juice tolerance that mimic host conditions was also evaluated by providing artificial conditions. Cellular adhesion and aggregation properties like auto- and co-aggregation were also checked and their results reflect all in the favor of lead probiotic strains.202537731160
6041130.9995Gut commensal bacteria show beneficial properties as wildlife probiotics. Probiotics are noninvasive, environmentally friendly alternatives for reducing infectious diseases in wildlife species. Our aim in the present study was to evaluate the potential of gut commensals such as lactic acid bacteria (LAB) as wildlife probiotics. The LAB selected for our analyses were isolated from European badgers (Meles meles), a wildlife reservoir of bovine tuberculosis, and comprised four different genera: Enterococcus, Weissella, Pediococcus, and Lactobacillus. The enterococci displayed a phenotype and genotype that included the production of antibacterial peptides and stimulation of antiviral responses, as well as the presence of virulence and antibiotic resistance genes; Weissella showed antimycobacterial activity owing to their ability to produce lactate and ethanol; and lactobacilli and pediococci modulated proinflammatory phagocytic responses that associate with protection against pathogens, responses that coincide with the presence of immunomodulatory markers in their genomes. Although both lactobacilli and pediococci showed resistance to antibiotics, this was naturally acquired, and almost all isolates demonstrated a phylogenetic relationship with isolates from food and healthy animals. Our results show that LAB display probiotic benefits that depend on the genus, and that lactobacilli and pediococci are probably the most obvious candidates as probiotics against infectious diseases in wildlife because of their food-grade status and ability to modulate protective innate immune responses.202032026493
4673140.9995Whole-genome analysis of probiotic product isolates reveals the presence of genes related to antimicrobial resistance, virulence factors, and toxic metabolites, posing potential health risks. BACKGROUND: Safety issues of probiotic products have been reported frequently in recent years. Ten bacterial strains isolated from seven commercial probiotic products on market were evaluated for their safety, by whole-genome analysis. RESULTS: We found that the bacterial species of three probiotic products were incorrectly labeled. Furthermore, six probiotic product isolates (PPS) contained genes for the production of toxic metabolites, while another three strains contained virulence genes, which might pose a potential health risk. In addition, three of them have drug-resistance genes, among which two strains potentially displayed multidrug resistance. One isolate has in silico predicted transferable genes responsible for toxic metabolite production, and they could potentially transfer to human gut microflora or environmental bacteria. Isolates of Lactobacillus rhamnosus and Bifidobacterium animalis subsp. lactis are associated with low risk for human consumption. Based on a comparative genome analysis, we found that the isolated Enterococcus faecium TK-P5D clustered with a well-defined probiotic strain, while E. faecalis TK-P4B clustered with a pathogenic strain. CONCLUSIONS: Our work clearly illustrates that whole-genome analysis is a useful method to evaluate the quality and safety of probiotic products. Regulatory quality control and stringent regulations on probiotic products are needed to ensure safe consumption and protect human health.202133761872
6043150.9995Histamine and cholesterol lowering abilities of lactic acid bacteria isolated from artisanal Pico cheese. AIMS: This study was designed to select lactic acid bacteria with histamine- and cholesterol-reducing abilities to be used as potential probiotics. METHODS AND RESULTS: Thirty strains of lactic acid bacteria isolated from an artisanal raw milk cheese were screened for their abilities to degrade histamine, reduce cholesterol and hydrolyse bile salts. Strains were also screened for safety and probiotic traits, such as resistance to gastrointestinal conditions, adhesion to Caco-2 cells, resistance to antibiotics and presence of virulence genes. Two Lactobacillus paracasei strains presented high cholesterol- and histamine-lowering abilities, tested negative for the presence of virulence genes and showed susceptibility to most important antibiotics. These strains were also shown to possess desirable in vitro probiotic properties, revealed by tolerance to gastrointestinal conditions and high adhesion to intestinal cells. CONCLUSIONS: Among the screened strains, Lb. paracasei L3C21M6 revealed the best cholesterol and histamine reducing abilities together with desirable probiotic and safety features to be used in food applications. SIGNIFICANCE AND IMPACT OF THE STUDY: The strain L3C21M6 is a good candidate for use as a probiotic with histamine-degrading activity and cholesterol lowering effect. In addition, this strain could be use in dairy foods to prevent histamine food poisoning.202032500572
6039160.9995Genome Characterization and Probiotic Potential of Corynebacterium amycolatum Human Vaginal Isolates. The vaginal microbiome of healthy women contains nondiphtheria corynebacteria. The role and functions of nondiphtheria corynebacteria in the vaginal biotope are still under study. We sequenced and analysed the genomes of three vaginal C. amycolatum strains isolated from healthy women. Previous studies have shown that these strains produced metabolites that significantly increased the antagonistic activity of peroxide-producing lactic acid bacteria against pathogenic and opportunistic microorganisms and had strong antimicrobial activity against opportunistic pathogens. Analysis of the C. amycolatum genomes revealed the genes responsible for adaptation and survival in the vaginal environment, including acid and oxidative stress resistance genes. The genes responsible for the production of H(2)O(2) and the synthesis of secondary metabolites, essential amino acids and vitamins were identified. A cluster of genes encoding the synthesis of bacteriocin was revealed in one of the annotated genomes. The obtained results allow us to consider the studied strains as potential probiotics that are capable of preventing the growth of pathogenic microorganisms and supporting colonisation resistance in the vaginal biotope.202235208706
6038170.9994Genomic Comparison of Lactobacillus helveticus Strains Highlights Probiotic Potential. Lactobacillus helveticus belongs to the large group of lactic acid bacteria (LAB), which are the major players in the fermentation of a wide range of foods. LAB are also present in the human gut, which has often been exploited as a reservoir of potential novel probiotic strains, but several parameters need to be assessed before establishing their safety and potential use for human consumption. In the present study, six L. helveticus strains isolated from natural whey cultures were analyzed for their phenotype and genotype in exopolysaccharide (EPS) production, low pH and bile salt tolerance, bile salt hydrolase (BSH) activity, and antibiotic resistance profile. In addition, a comparative genomic investigation was performed between the six newly sequenced strains and the 51 publicly available genomes of L. helveticus to define the pangenome structure. The results indicate that the newly sequenced strain UC1267 and the deposited strain DSM 20075 can be considered good candidates for gut-adapted strains due to their ability to survive in the presence of 0.2% glycocholic acid (GCA) and 1% taurocholic and taurodeoxycholic acid (TDCA). Moreover, these strains had the highest bile salt deconjugation activity among the tested L. helveticus strains. Considering the safety profile, none of these strains presented antibiotic resistance phenotypically and/or at the genome level. The pangenome analysis revealed genes specific to the new isolates, such as enzymes related to folate biosynthesis in strains UC1266 and UC1267 and an integrated phage in strain UC1035. Finally, the presence of maltose-degrading enzymes and multiple copies of 6-phospho-β-glucosidase genes in our strains indicates the capability to metabolize sugars other than lactose, which is related solely to dairy niches.201931293536
8468180.9994Development and validation of a species-independent functional gene microarray that targets lactic acid bacteria. During the last few years, genome-related information has become available for many microorganisms, including important food-related bacteria. Lactic acid bacteria (LAB) are important industrially in the production of fermented foods such as dairy products, sausages, sourdoughs, and vegetables. Despite their limited metabolic capacity, LAB contribute considerably to important characteristics of fermented foods, such as flavor and texture. In the present study, a species-independent functional gene microarray was developed that targets 406 genes that play key roles in the production of sugar catabolites, bacteriocins, exopolysaccharides, and aromas, in probiotic and biosafety characteristics, and in the stress response. Also, genes linked to negative traits, such as antibiotic resistance and virulence, are represented. As LAB ecosystems contain a variety of species, there was a more global focus on these specific functional properties. Thus, an algorithm was used to design gene-specific oligonucleotides that preferably hybridize with multiple LAB species, thereby allowing controlled cross-hybridization. For proof of concept, the microarray composed of 2,269 30-mer oligonucleotides focused on LAB species that are prevalent in sourdough ecosystems. Validation hybridizations using DNA and RNA from 18 LAB strains, covering 86% of all the oligonucleotides, showed that there were wide ranges in intensity and high reproducibility between microarrays.200919684161
6067190.9994Technology and safety assessment for lactic acid bacteria isolated from traditional Bulgarian fermented meat product "lukanka". The present work discusses the technological and new selection criteria that should be included for selecting lactic acid bacteria for production of fermented meat. Lactic acid bacteria isolated from Bulgarian traditional fermented "lulanka" salami was studied regarding some positive technological parameters (growth at different temperature, pH, and proteolytic activity). The presence of genes related to the virulence factors, production of biogenic amines, and vancomycin resistance were presented in low frequency in the studied lactic acid bacteria. On the other hand, production of antimicrobial peptides and high spread of bacteriocin genes were broadly presented. Very strong activity against L. monocytogenes was detected in some of the studied lactic acid bacteria. In addition, the studied strains did not present any antimicrobial activity against tested closely related bacteria such as Lactobacillus spp., Lactococcus spp., Enterococcus spp. or Pediococcus spp. To our knowledge this is the first study on the safety and antimicrobial properties of lactic acid bacteria isolated from Bulgarian lukanka obtained by spontaneous fermentation.201728552660