Promising Probiotic Strain Research Articles

A probiotic Lacticaseibacillus paracacei isolate from traditional Chinese fermented mung bean juice capable of alleviating oxidative stress in colorectal cells

Traditional fermented mung bean juice (FMJ) has hundreds of years' consumption history in North China with known health benefits, and thus could be a valuable source for uncovering novel probiotics. In this study, we discovered a probiotic isolate with good antioxidant bioactivity from FMJ. First, we conducted 16 S rRNA amplicon analysis on 14 samples of two types of FMJ, Douzhir and Fenjiang, collected from Beijing and Henan Province, respectively. The dominant genera were Lactobacillus, Lactococcus, Weissella and Streptococcus, and the abundance of Weissella was significantly higher in Fenjiang than in Douzhir. Based on rank-sum ratio evaluation of 21 selected isolates, seven isolates identified as Lacticaseibacillus fermentum (Lactobacillus fermentum), Lactiplantibacillus plantarum (Lactobacillus plantarum), Limosilactobacillus paracasei (Lactobacillus paracasei), Lentilactobacillus parabuchneri (Lactobacillus parabuchneri) and Levilactobacillus brevis (Lactobacillus brevis), exhibited good tolerance to acid (pH 2.5) and bile salt (0.3%), high cell surface hydrophobicity and auto-aggregation, and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and DPPH (2,2-Diphenyl-1-picrylhydrazyl) scavenging rates, without antibiotic resistance or hemolytic activity, and were further tested in cell assays. The cell-free extract of L. paracacei D1-10 showed significant protective effects on HT29 colon cell viability under 300–600 μM H2O2 treatments. These findings suggested FMJ is a valuable source for probiotic exploration, and D1-10 might be a promising probiotic strain with good antioxidant potential.

Exploring the genomic traits of infant-associated microbiota members from a Zimbabwean cohort

IntroductionOur understanding of particular gut microbiota members such as Bifidobacterium and Enterococcus in low-middle-income countries remains very limited, particularly early life strain-level beneficial traits. This study addresses this gap by exploring a collection of bacterial strains isolated from the gut of Zimbabwean infants; comparing their genomic characteristics with strains isolated from infants across North America, Europe, and other regions of Africa.Materials and methodFrom 110 infant stool samples collected in Harare, Zimbabwe, 20 randomly selected samples were used to isolate dominant early-life gut microbiota members Bifidobacterium and Enterococcus. Isolated strains were subjected to whole genome sequencing and bioinformatics analysis including functional annotation of carbohydrates, human milk oligosaccharide (HMO) and protein degradation genes and clusters, and the presence of antibiotic resistance genes (ARGs).ResultsThe study observed some location-based clustering within the main five identified taxonomic groups. Furthermore, there were varying and overall species-specific numbers of genes belonging to different GH families encoded within the analysed dataset. Additionally, distinct strain- and species-specific variances were identified in the potential of Bifidobacterium for metabolizing HMOs. Analysis of putative protease activity indicated a consistent presence of gamma-glutamyl hydrolases in Bifidobacterium, while Enterococcus genomes exhibited a high abundance of aspartyl peptidases. Both genera harboured resistance genes against multiple classes of antimicrobial drugs, with Enterococcus genomes containing a higher number of ARGs compared to Bifidobacterium, on average.ConclusionThis study identified promising probiotic strains within Zimbabwean isolates, offering the potential for early-life diet and microbial therapies. However, the presence of antibiotic resistance genes in infant-associated microbes raises concerns for infection risk and next-stage probiotic development. Further investigation in larger cohorts, particularly in regions with limited existing data on antibiotic and probiotic use, is crucial to validate these initial insights.Impact statementThis research represents the first investigation of its kind in the Zimbabwean context, focusing on potential probiotic strains within the early-life gut microbiota. By identifying local probiotic strains, this research can contribute to the development of probiotic interventions that are tailored to the Zimbabwean population, which can help address local health challenges and promote better health outcomes for infants. Another essential aspect of the study is the investigation of antimicrobial resistance genes present in Zimbabwean bacterial strains. Antimicrobial resistance is a significant global health concern, and understanding the prevalence and distribution of resistance genes in different regions can help inform public health policies and interventions.

Draft genome sequences of Weissella cibaria GM93m3, a promising probiotic strain from raw goat milk.

The draft genome of a previously documented potential probiotic Weissella cibaria strain GM93m3 from raw goat milk in Nigeria is reported. The total genome size was 2,447,229 with 46 contigs and G+C content of 44.86%.

Streptomyces sp. MUM 195J: A Promising Probiotic for Controlling Vibrio parahaemolyticus Infection in Aquaculture

Aquaculture is gaining prominence in meeting the increasing global food demand. However, persistent episodes of pathogenic infections have greatly affected production and incurred substantial financial losses to the industry. Regrettably, there is a lack of effective contemporary therapeutic measures to control infectious diseases in aquaculture. The repercussions of antimicrobial resistance have underscored the drawbacks of the contemporary practice of relying solely on antibiotics in disease control. The aquaculture industry needs a safer, environmentally viable, and economically efficient means for disease management. In this regard, this study aims to investigate the effectiveness of mangrove-derived Streptomyces sp. probiotics in controlling Vibrio parahaemolyticus infections. In vitro screenings were undertaken to evaluate the inhibitory activity of five Streptomyces sp. isolates. Subsequently, a series of in vivo trials was conducted, with the Malaysian giant freshwater prawn, Macrobrachium rosenbergii larvae as the animal model. Following that, molecular analyses were employed to examine the changes in gene expression. In essence, Streptomyces sp. MUM 195J emerges as a promising probiotic strain that demonstrates a strong inhibitory effect against V. parahaemolyticus. Its application as a feed additive elevates the survival rate of M. rosenbergii threefold, thus demonstrating efficacy at par with florfenicol antibiotic when challenged with the V. parahaemolyticus pathogen. Besides, Streptomyces sp. MUM 195J elevated the growth rate of M. rosenbergii by 17%. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis revealed that probiotic supplementation elevated the immune function of the animal. Additionally, Streptomyces sp. MUM 195J demonstrates the potential to ameliorate the quality of the rearing water.

Screening of probiotic strains to improve visceral hypersensitivity in irritable bowel syndrome by using in vitro and in vivo approaches.

Oral administration of probiotics has been proposed as a promising biotherapy to prevent and treat different diseases related to gastrointestinal disorders, such as irritable bowel syndrome (IBS). Due to the increasing research area on the characterisation of new probiotic bacterial strains, it is necessary to perform suitable in vitro experiments, using pertinent cellular models, in order to establish appropriate readout profiles based on IBS symptoms and subtypes. In this work, a collection of 30 candidate strains, belonging mainly to the Lactobacillus and Bifidobacterium genera, were screened using three different sets of in vitro experiments with different readouts to identify promising probiotic strains with: (1) the ability to inhibit the synthesis of IL-8 production by TNF-α stimulated HT-29 cells, (2) immunomodulatory properties quantified as increased IL-10 levels in peripheral blood mononuclear cell (PBMCs), and (3) the ability to maintain epithelial barrier integrity by increasing the trans-epithelial/endothelial electrical resistance (TEER) values in Caco-2 cells. Based on these criteria, three strains were selected: Lactobacillus gasseri PI41, Lacticaseibacillus rhamnosus PI48 and Bifidobacterium animalis subsp. lactis PI50, and tested in a murine model of low-grade inflammation induced by dinitrobenzene sulfonic acid (DNBS), which mimics some of the symptoms of IBS. Among the three strains, L. gasseri PI41 improved overall host well-being by preventing body weight loss in DNBS-treated mice and restored gut homeostasis by normalising the intestinal permeability and reducing pro-inflammatory markers. Therefore, the potential of this strain was confirmed in a second murine model known to reproduce IBS symptoms: the neonatal maternal separation (NMS) model. The PI41 strain was effective in preventing intestinal permeability and reducing colonic hypersensitivity. In conclusion, the set of in vitro experiments combined with in vivo assessments allowed us to identify a promising probiotic candidate strain, L. gasseri PI41, in the context of IBS.

Evaluation of antioxidant activity and fermentation properties of potential probiotic strain Lactiplantibacillus plantarum HY7720 in plant-based materials

People on vegan diets are at risk of being deficient in varied nutrients such as vitamin B12 and certain amino acids. In this study, we investigated vitamin B12-producing lactic acid bacteria (LAB) as well as the probiotic and antioxidant properties. Lactiplantibacillus plantarum HY7720 was screened from 22 strains of LAB that were isolated from different plant foods, and its growth ability and extracellular vitamin B12-producing capacity in vitamin B12-deficient medium were investigated. To determine whether HY7720 functions as a probiotic, survival rate in the simulated gastrointestinal tract and adhesion property to human intestinal epithelial cells of HY7720 were compared with positive control, Lacticaseibacillus rhamnosus GG (LGG). Moreover, the results showed that HY7720 recovered the gene expression levels of tight junction-associated proteins (TJPs), including TJP1, TJP2, occludin (OCLN), and claudin-1 (CLDN1) and inhibited the secretion levels of pro-inflammatory cytokines, including interleukin (IL)-6 and IL-8, in tumor necrosis factor (TNF)-α-stimulated Caco-2 cells. Furthermore, we verified that HY7720 exhibit the antioxidant potential, by showing its intracellular reactive oxygen species (ROS) scavenging ability in hydrogen peroxide (H2O2)-stimulated Caco-2 cells. The ability of HY7720 to ameliorate H2O2-induced cytotoxicity in Caco-2 cells was inhibited by mitogen-activated protein kinase (MAPK) inhibitors, indicating that its antioxidant responses are related to extracellular signal-regulated kinase (ERK) and c-JUN N-terminal kinase (JNK). This study also investigated the nutritional qualities of three plant-based materials (brown rice, white rice, and soy milk) fermented using HY7720. Collectively, HY7720 could be used as a promising probiotic strain for the prevention of nutritional deficiencies among people on vegetarian diets.

Inhibition effect of aerobic respiratory Lactococcus lactis on Salmonella enterica subsp. enterica serovar Typhimurium SL 1344 and its intestinal colonization ability

Lactococcus lactis undergoing aerobic respiration can consume oxygen and form an anaerobic environment. Salmonella, as a facultative anaerobic foodborne pathogen, multiply better under aerobic conditions. The purpose of this study was to explore aerobic respiration of Lactococcus lactis subsp. lactis (L. lactis) KLDS 4.0325 inhibitory effect on Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) SL 1344 in vitro and its colonization ability in vivo. Results indicate that L. lactis KLDS 4.0325 could inhibit the growth of S. Typhimurium SL1344 by producing bacteriocin. And L. lactis KLDS 4.0325 undergoing aerobic respiration could enhance this inhibitory effect, while reducing the expression levels of virulence genes sipB, sipC, and sopE2 in S. Typhimurium SL1344. L. lactis KLDS 4.0325 could be successfully labeled by CFDA-SE fluorescent probe, and the labeling rate was more than 97%. Murine experiments showed that L. lactis KLDS 4.0325 could adhere and colonize in the cecum and colon. Thus, L. lactis KLDS 4.0325 is a promising probiotic strain for the potential inhibition of Salmonella infection via its oxygen-scavenging in host gut.

What happens to Bifidobacterium adolescentis and Bifidobacterium longum ssp. longum in an experimental environment with eukaryotic cells?

BackgroundThe impact of probiotic strains on host health is widely known. The available studies on the interaction between bacteria and the host are focused on the changes induced by bacteria in the host mainly. The studies determining the changes that occurred in the bacteria cells are in the minority. Within this paper, we determined what happens to the selected Bifidobacterium adolescentis and Bifidobacterium longum ssp. longum in an experimental environment with the intestinal epithelial layer. For this purpose, we tested the bacteria cells' viability, redox activity, membrane potential and enzymatic activity in different environments, including CaCo-2/HT-29 co-culture, cell culture medium, presence of inflammatory inductor (TNF-α) and oxygen.ResultsWe indicated that the external milieu impacts the viability and vitality of bacteria. Bifidobacterium adolescentis decrease the size of the live population in the cell culture medium with and without TNF-α (p < 0.001 and p < 0.01 respectively). In contrast, Bifidobacterium longum ssp. longum significantly increased survivability in contact with the eukaryotic cells and cell culture medium (p < 0.001). Bifidobacterium adolescentis showed significant changes in membrane potential, which was decreased in the presence of eukaryotic cells (p < 0.01), eukaryotic cells in an inflammatory state (p < 0.01), cell culture medium (p < 0.01) and cell culture medium with TNF-α (p < 0.05). In contrast, Bifidobacterium longum ssp. longum did not modulate membrane potential. Instead, bacteria significantly decreased the redox activity in response to milieus such as eukaryotic cells presence, inflamed eukaryotic cells as well as the culture medium (p < 0.001). The redox activity was significantly different in the cells culture medium vs the presence of eukaryotic cells (p < 0.001). The ability to β-galactosidase production was different for selected strains: Bifidobacterium longum ssp. longum indicated 91.5% of positive cells, whereas Bifidobacterium adolescentis 4.34% only. Both strains significantly reduced the enzyme production in contact with the eukaryotic milieu but not in the cell culture media.ConclusionThe environmental-induced changes may shape the probiotic properties of bacterial strains. It seems that the knowledge of the sensitivity of bacteria to the external environment may help to select the most promising probiotic strains, reduce research costs, and contribute to greater reproducibility of the obtained probiotic effects.

The anti-hyperuricemic and gut microbiota regulatory effects of a novel purine assimilatory strain, Lactiplantibacillus plantarum X7022.

Probiotics have been reported to effectively alleviate hyperuricemia and regulate the gut microbiota. The aim of this work was to study the in vivo anti-hyperuricemic properties and the mechanism of a novel strain, Lactiplantibacillus plantarum X7022. Purine content and mRNA expression of purine assimilation related enzymes were determined by HPLC and qPCR, respectively. Hyperuricemic mice were induced by potassium oxonate and hypoxanthine. Uric acid (UA), blood urea nitrogen, creatinine and renal inflammation were examined by kits. The expression of renal UA transporters was subjected to western blotting. Kidney tissues were sectioned for histological analysis. The fecal short-chain fatty acids (SCFAs) were determined by HPLC, and gut microbiota was investigated using the 16S rDNA metagenomic sequencing. L. plantarum X7022 possesses a complete purine assimilation pathway and can exhaust xanthine, guanine, and adenine by 82.1%, 33.1%, and 12.6%, respectively. The strain exhibited gastrointestinal viability as 44% at the dose of 109CFU/mL in mice. After four-week administration of the strain, a significant decrease of 35.5% in the serum UA level in hyperuricemic mice was achieved. The diminished contents of fecal propionate and butyrate were dramatically boosted. The treatment also alleviated renal inflammation and restored renal damage. The above physiological changes may due to the inhibited xanthine oxidase (XO) activity, as well as the expressional regulation of UA transporters (GLUT9, URAT1 and OAT1) to the normal level. Notably, gut microbiota dysbiosis in hyperuricemic mice was improved with the inflammation and hyperuricemia related flora depressed, and SCFAs production related flora promoted. The strain is a promising probiotic strain for ameliorating hyperuricemia.

Screening and Production of Industrially Relevant Enzymes by Bacillus paranthracis Strain MHDS3, a Potential Probiotic

The digestive process and intestinal protein absorption are influenced by a variety of factors. Due to their numerous health advantages, including potential favorable effects on protein digestion and absorption, probiotics have gained increased attention in recent years. Probiotics can control the intestinal microflora, which in turn affects the intestinal bacteria responsible for proteolysis. Additionally, certain probiotics can release exoenzymes that aid in the digestion of proteins and others can stimulate the host’s digestive protease and peptidase activity. By boosting transport and enhancing the epithelium’s capacity for absorption, probiotics can also improve the absorption of tiny peptides and amino acids as well as lessen detrimental protein fermentation, which lowers the toxicity of metabolites. The present study explored the production of enzymes by Bacillus paranthracis strain MHDS3, a probiotic candidate isolated from Pellaea calomelanos. Bacillus paranthracis displayed enzyme activities of amylase (31,788.59 IU), cellulase (4487.486 IU), and pectinase (13.98986 IU) through submerged fermentation. The CAZyme analysis of B. paranthracis revealed 16 CAZyme gene clusters associated with cellulose, amylase, and pectinase activity. Thus, B. paranthracis is a promising probiotic strain that can produce enzymes with biotechnological applications.

Molecular 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.

Probiotic and functional potential of lactic acid bacteria isolated from pulque and evaluation of their safety for food applications.

Pulque is a traditional Mexican non-distilled alcoholic beverage to which several beneficial functions are attributed, mainly associated with gastrointestinal health, which can be explained by the presence of probiotic bacteria in its microbiota. Therefore, the objective of this work was to evaluate the safety, probiotic activity, and functional characteristics of seven strains of lactic acid bacteria (LAB) isolated from pulque using the probiotic strain Lactobacillus acidophilus NCFM as control. The LAB isolates were identified by 16S rRNA sequencing and MALDI Biotyper® MS as belonging to three different Lactobacillaceae genera and species: Lactiplantibacillus plantarum, Levilactobacillus brevis and Lacticaseibacillus paracasei. Most strains showed resistance to gastric juice, intestinal juice and lysozyme (10 mg/L). In addition, all strains exhibited bile salt hydrolase (BSH) activity and antibacterial activity against the pathogenic strain Listeria monocytogenes. Additionally, cell surface characteristics of LAB were evaluated, with most strains showing good hydrophobicity, auto-aggregation, and co-aggregation towards enteropathogenic Escherichia coli and L. monocytogenes. In terms of safety, most of the strains were sensitive to the tested antibiotics and only the Lact. paracasei UTMB4 strain amplified a gene related to antibiotic resistance (mecA). The strains Lact. plantarum RVG2 and Lact. plantarum UTMB1 presented γ-hemolytic activity, and the presence of the virulence-related gene agg was identified only in UTMB1 strain. Regarding functional characterization, the tested bacteria showed good β-galactosidase activity, antioxidant activity and cholesterol reduction Based on principal component analysis (PCA) and heat mapping, and considering the strain Lact. acidophilus NCFM as the probiotic reference, the strains Lacticaseibacillus paracasei UTMB4, Lactiplantibacillus plantarum RVG4 and Levilactobacillus brevis UTMB2 were selected as the most promising probiotic strains. The results of this study highlighted the probiotic, functional and safety traits of LAB strains isolated from pulque thus supporting the health benefits attributed to this ancestral beverage.

Systematic Investigation of the Effect of Lactobacillus acidophilus TW01 on Potential Prevention of Particulate Matter (PM)2.5-Induced Damage Using a Novel In Vitro Platform.

Exposure to ambient particulate matter (PM) and cigarette smoking (CS) is a risk factor for respiratory/lung infections and metabolic disorders. Lung-gut axis disruption involving the upregulation of oxidative stress, systemic inflammation, and gut barrier dysfunction by PM is one of the potential mechanisms. Thus, we designed a novel in vitro platform for pre-selecting probiotics with potentially protective effects against PM-induced lung damage through the lung-gut axis to reduce animal usage. The results showed that a high dose of Lactobacillus acidophilus TW01 (1 × 108 CFU/mL) inhibited reactive oxygen species (ROS) production. This strain could also reduce respiratory epithelial cell death induced by cigarette smoke extraction (CSE), as well as promoting Caco-2 cell migration in 1 × 106 CFU/mL. Although further animal experiments are needed to validate the in vitro findings, L. acidophilus TW01 is a promising probiotic strain for the potential prevention of PM2.5-induced damage.

Genome Analysis of Potential Probiotic Levilactobacillus brevis AcCh91 Isolated from Indian Home-Made Fermented Milk Product (Chhurpi).

Consumption of naturally fermented milk (NFM) products is the dietary culture in India. The mountainous people of Arunachal Pradesh in India prepare the assorted artisanal home-made NFM products from cow and yak milk. Previously, we isolated and identified 76 strains of lactic acid bacteria (LAB) from NFM products of Arunachal Pradesh, viz. mar, chhurpi and churkam. We hypothesized that some of these LAB strains may possess probiotic potentials; hence, we investigated the probiotic potentials of these strains. On the basis of in vitro and genetic screening for probiotic attributes including haemolytic ability, 20 LAB strains were selected out of 76 strains, for further analysis. Using in silico analysis, viz. multivariate heatmap and PCA (principal component analysis) biplot, Levilactobacillus brevis AcCh91 was selected as the most promising probiotic strain, which was further characterized by the whole-genome analysis. Lev. brevis AcCh91 showed the highest survival rate of 93.38% in low pH and 86.68 ± 2.69% in low bile and the highest hydrophobicity average of 86.34 ± 5.53%. This strain also showed auto-aggregation and co-aggregation with antimicrobial properties against the pathogens, showed ability to produce beta-galactosidase and cholesterol reduction property and, most importantly, produced GABA, an important psychobiotic element. Genomic analysis of Lev. brevis AcCh91 showed the presence of genes corresponding to GABA, vitamins, amino acids, cholesterol reduction, immunomodulation, bioactive peptides and antioxidant activity. The absence of antimicrobial-resistant genes and virulence factors was observed. Hence, genome analysis supports the probiotic potentials of Lev. brevis AcCh91, which may be further investigated to understand its health-promoting properties.

Clinical effect of Pediococcus acidilactici PMC48 on hyperpigmented skin.

The excessive production and accumulation of melanin in the epidermal skin layer can result in skin hyperpigmentation and darkening. Current technologies for regulating melanin are based on inhibiting melanin biosynthesis. They have low effectiveness and safety issues. This study aimed to evaluate the potential role of Pediococcus acidilactici PMC48 as a probiotic strain in medicines and cosmetics for skin treatment. Meanwhile, our research team has reported that P. acidilactici PMC48 strain isolated from sesame leaf kimchi can directly decompose the already synthesized melanin. It can also inhibit melanin biosynthesis. In the present study, we investigated the skin-whitening effect of this strain by arranging an 8-week clinical trial with 22 participants. PMC48 was applied to each participant's artificially UV-induced tanned skin in the clinical trial. Its whitening effect was investigated based on visual evaluation, skin brightness, and melanin index. PMC48 showed a significant effect on the artificially induced pigmented skin. The color intensity of the tanned skin was decreased by 47.647%, and skin brightness was increased by 8.098% after the treatment period. PMC48 also significantly decreased the melanin index by 11.818%, indicating its tyrosinase inhibition capacity. Also, PMC48 improved skin moisture content level by 20.943%. Additionally, 16S rRNA-based amplicon sequencing analysis showed a distinct increase in Lactobacillaceae in the skin by up to 11.2% at the family level without affecting other skin microbiota. Furthermore, it showed no toxicity in in vitro or in vivo analyses. These results indicate that P. acidilactici PMC48 is a promising probiotic strain that can be used to develop medicines and cosmetic products to solve skin-related problems. These results demonstrate that P. acidilactici PMC48 can be a potential probiotic for the cosmetic industry against different skin disorders.

Чутливість до антибактеріальних препаратів штамів Bacillus spp. з високим рівнем антагоністичної активності для виготовлення пробіотиків

The development of organic livestock farming, in particular poultry farming, which Ukraine is targeting, requires a radical change in approaches to the prevention and treatment of infectious diseases. The macroorganism and microbiota of the gastrointestinal tract constitute a single ecological system with homeostatic balance. However, its violation creates a threat of an imbalance of intestinal normal flora and the development of diseases of bacterial etiology in poultry. Considering this, there is a growing need for the development and use of probiotic preparations. The high antagonistic potential of bacteria of the genus Bacillus in relation to other pathogens causes scientific and industrial interest in the development of probiotics with their involvement in the composition of these bacteria as an alternative to antibiotics. But due to the existence of risks of direct transfer of R-plasmids of antibiotic resistance to the biotic microflora of the gastrointestinal tract together with probiotic strains when they acquire resistance, promising strains of bacteria of the genus Bacillus should be tested for sensitivity to antibiotic drugs. We selected promising probiotic strains with a high level of antagonism, Bacillus subtilis Bs-5 and Bs-9, Bacillus licheniformis Bfl-1 and Bfl-4, Bacillus coagulans Bcg-5, Bacillus amyloliquefaciens Baf-1 and Baf-3 showed full sensitivity to the applied antibiotics — representatives of the groups of carbapenems, fluoroquinolones, glycopeptides, lincosamides, macroliths and oxazolidones. These strains were recommended as probiotic, antibiotic sensitive, safe and promising for their use in the design of probiotic preparations. The obtained results of laboratory studies of other strains of B. subtilis, B. licheniformis, B. coagulans, B. amyloliquefaciens proved the presence among them of bacteria polyresistant to fluoroquinolone, carbapenem, macrolide and glycopeptide antibiotics.

Effects of Lactobacillus reuteri MG5346 on Receptor Activator of Nuclear Factor-Kappa B Ligand (RANKL)-Induced Osteoclastogenesis and Ligature-Induced Experimental Periodontitis Rats.

Effects of culture supernatants of Lactobacillus reuteri MG5346 (CS-MG5346) on receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis were examined. CS-MG5346 treatment up to 400 μg/mL significantly reduced tartrate-resistant acid-phosphatase (TRAP) activity, the phenotype biomarker of osteoclast, without affecting cell viability. CS-MG5346 inhibited the expression of osteoclast specific transcriptional factors (c-fos and nuclear factor-activated T cells c1) and their target genes (TRAP, cathepsin, and matrix metallo-proteinase-9) in a dose-dependent manner (p<0.05). The administration of L. reuteri MG5346 (2×108 CFU/day) for 8 wks significantly improved furcation involvement, but no difference was observed in alveolar bone loss in ligature-induced experimental periodontitis rats. The elevated RANKL/ osteoprotegerin ratio, the biomarker of periodontitis, was significantly lowered in the gingival tissue by administration of L. reuteri MG5346 (p<0.05). L. reuteri MG5346 showed excellent stability in simulated stomach and intestinal fluids and did not have antibiotic resistance. Based on the results, L. reuteri MG5346 has the potential to be a promising probiotic strain for oral health.

Metabolite composition of probiotic strain lactobacillus paracasei B-11821

Lactobacillus paracasei B-11821 is a probiotic strain of microorganisms, for which previous studies have shown pronounced antagonistic and adhesive activity, a high level of acid formation and manufacturability. The characteristics of the metabolite profile of the promising probiotic strain can significantly expand the scope of its application in the medical, pharmaceutical and food industries. Using high- performance liquid chromatomass spectrometry and gas-liquid chromatography, it was established that this strain is an active producer of essential amino acids: (isoleucine (1.920 mg/mL), phenylalanine (0.963 mg/mL), valine (0.840 mg/mL), leucine (0.561 mg/mL), methionine (0.369 mg/mL), threonine (0.233 mg/mL), histidine (0.055 mg/mL), lysine (0.008 mg/mL)); as well as a number of replaceable amino acids (tyrosine (0.622 mg/mL), alanine (0.438 mg/mL), proline (0.278 mg/mL), glycine (0.111 mg/mL), glutamine (0.015 mg/mL), asparagine (0.014 mg/mL), serine (0.008 mg/mL), arginine (0.005 mg/mL)). The strain is also an active producer of organic acids (lactic (16.2 mg/ml), acetic (0.9 mg/ml) and gamma-aminobutyric (0.3 mg/ml) GABA, propionic (0.02 mg/ml) acids. The obtained results can be used for development based on the strain Lactobacillus paracasei B-11821 probiotic preparations, functional food products, technologies for synthesis of lactic and gamma-aminobutyric acids.

Evaluation of antibiotic sensitivity of potential probiotic Bacillus strains isolated from chicken and pig feces

Nowadays, the misuse and overuse of antibiotics in livestock production leads to the appearance of antibiotic resistant strains that promotes the use of probiotics in feed to minimise/replace antibiotic consumption. Among them, Bacilli are common supplements for feed effectiveness and livestock health benefits. However, there is a growing concern about the development of antibiotic resistance and transfer of antibiotic resistance genes among bacteria. Thus, the European Food Safety Authority (EFSA) has suggested that products containing Bacillus strains intended to use as feed additive must be examined for susceptibility to antimicrobials of human and veterinary importance. In this study, the antibiotic susceptibility of potential probiotic Bacillus strains was investigated. A total of 59 Bacillus species were isolated from 10 samples of chicken and pig feces. Then, the in vitro probiotic characteristics including low pH tolerance, catalase activity, protease, amylase and cellulase enzymes production were tested to select appropriate isolates for further studies. Thirty-three promising probiotic strains were assessed for their antibiotic susceptibility against 13 antibiotics by disc diffusion method. In most cases, isolated Bacillus strains were susceptible to tested antibiotics. The obtained results demonstrated the potential application of Bacillus spp. as feed supplements in animal production.

In Vitro Probiotic Characterization and Safety Assessment of Lactic Acid Bacteria Isolated from Raw Milk of Japanese-Saanen Goat (Capra hircus)

Two novel probiotic strains of lactic acid bacteria were successfully isolated from the raw milk of dairy Japanese-Saanen goats. Selection criteria for positive candidates were grown on de Man-Rogosa-Sharpe or M17 selective medium at 30, 35, or 42 °C anaerobically, and characterized based on Gram reaction, catalase test, and tolerance to low pH and bile salts. Among the 101 isolated positive candidates, two strains, YM2-1 and YM2-3, were selected and identified as Lacticaseibacillus rhamnosus using 16S rDNA sequence similarity. Culture supernatants of the two strains exhibited antipathogenic activity against Salmonella enterica subsp. enterica serovar. Typhimurium, Shigella sonnei, methicillin-resistant Staphylococcus aureus, methicillin-sensitive Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157. The antipathogenic activities were retained to some extent after neutralization, indicating the presence of antipathogenic substances other than organic acids in the culture supernatants. The two strains were sensitive with coincidental minimum inhibition concentrations (indicated in the parentheses hereafter) to ampicillin (0.25 μg/mL), chloramphenicol (4 μg/mL), gentamycin (4 μg/mL), kanamycin (64 μg/mL), streptomycin (16 μg/mL), and tetracycline (4 μg/mL). Furthermore, the two strains were resistant to clindamycin (16 μg/mL) and erythromycin (4 μg/mL). In addition, both YM2-1 and YM2-3 strains showed less unfavorable activities, including bile acid bioconversion, carcinogenic-related enzymes, mucin degradation, plasminogen activation, and hemolysis, than the detection limits of in vitro evaluation methods used in this study. In summary, L. rhamnosus YM2-1 and YM2-3 are highly safe and promising probiotic strains applicable in the dairy industry, and were first isolated from the raw milk of Japanese-Saanen goats.