Probiotic assessment and antioxidant characterization of Lactobacillus plantarum GXL94 isolated from fermented chili

Assessment of the Safety and Probiotic Properties of Enterococcus faecium B13 Isolated from Fermented Chili

Enterococcus faecium B13, selected from fermentation chili, has been proven to promote animal growth by previous studies, but it belongs to opportunistic pathogens, so a comprehensive evaluation of its probiotic properties and safety is necessary. In this study, the probiotic properties and safety of B13 were evaluated at the genetic and phenotype levels in vitro and then confirmed in vivo. The genome of B13 contains one chromosome and two plasmids. The average nucleotide identity indicated that B13 was most closely related to the fermentation-plant-derived strain. The strain does not carry the major virulence genes of the clinical E. faecium strains but contains aac(6')-Ii, ant (6)-Ia, msrC genes. The strain had a higher tolerance to acid at pH 3.0, 4.0, and 0.3% bile salt and a 32.83% free radical DPPH clearance rate. It can adhere to Caco-2 cells and reduce the adhesion of E. coli to Caco-2 cells. The safety assessment revealed that the strain showed no hemolysis and did not exhibit gelatinase, ornithine decarboxylase, lysine decarboxylase, or tryptophanase activity. It was sensitive to twelve antibiotics but was resistant to erythromycin, rifampicin, tetracycline, doxycycline, and minocycline. Experiments in vivo have shown that B13 can be located in the ileum and colon and has no adverse effects on experiment animals. After 28 days of feeding, B13 did not remarkable change the α-diversity of the gut flora or increase the virulence genes. Our study demonstrated that E. faecium B13 may be used as a probiotic candidate.

Exploring the Preventive and Therapeutic Mechanisms of Probiotics in Chronic Kidney Disease through the Gut-Kidney Axis

Gut dysbiosis contributes to deterioration of chronic kidney disease (CKD). Probiotics are a potential approach to modulate gut microbiota and gut-derived metabolites to alleviate CKD progression. We aim to provide a comprehensive view of CKD-related gut dysbiosis and a critical perspective on probiotic function in CKD. First, this review addresses gut microbial alterations during CKD progression and the adverse effects associated with the changes in gut-derived metabolites. Second, we conduct a thorough examination of the latest clinical trials involving probiotic intervention to unravel critical pathways via the gut-kidney axis. Finally, we propose our viewpoints on limitations, further considerations, and future research prospects of probiotic adjuvant therapy in alleviating CKD progression. Enhancing our understanding of host-microbe interactions is crucial for gaining precise insights into the mechanisms through which probiotics exert their effects and identifying factors that influence the effectiveness of probiotics in developing strategies to optimize their use and enhance clinical outcomes.

The antioxidant activity and metabolomic analysis of the supernatant of Streptococcus alactolyticus strain FGM

Strain-specific probiotics can present antioxidant activity and reduce damage caused by oxidation. Streptococcus alactolyticus strain FGM (S. alactolyticus strain FGM) isolated from the chicken cecum shows potential probiotic properties which have been previously demonstrated. However, the antioxidant properties of S. alactolyticus strain FGM remain unknown. In this view, cell-free supernatant (CFS), intact cells (IC) and intracellular extracts (CFE) of strain FGM and 3 strains of Lactobacillus (LAB) were prepared, and their scavenging capacities against DPPH, hydroxyl radicals and linoleic acid peroxidation inhibitory were compared in this study. The effects of strain FGM cell-free supernatant (FCFS) on NO production, activity of SOD and GSH-Px in RAW264.7 cells and LPS-induced RAW264.7 cells were analyzed. The metabolites in the supernatant were quantitated by N300 Quantitative Metabolome. It was shown that the physicochemical characteristics of CFS to scavenge DPPH, hydroxyl radicals, and linoleic acid peroxidation inhibitory were significantly stronger than that of IC and CFE in the strain FGM (P < 0.05), respectively 87.12% ± 1.62, 45.03% ± 1.27, 15.63% ± 1.34. FCFS had a promotional effect on RAW264.7 cells, and significantly elevated SOD and GSH-Px activities in RAW264.7 cells. 25 μL FCFS significantly promoted the proliferation of RAW264.7 cells induced by LPS, increased the activities of SOD and GSH-PX, and decreased the release of NO. Furthermore, among the differential metabolites of FCFS quantified by N300, 12 metabolites were significantly up-regulated, including lactic acid, indole lactic acid, linoleic acid, pyruvic acid etc., many of which are known with antioxidant properties. In conclusion, FCFS had good antioxidant properties and activity, which can be attributed to metabolites produced from strain FGM fermentation. It was further confirmed that S. alactolyticus strain FGM and its postbiotic have potential probiotic properties and bright application prospects in livestock and poultry breeding.

Characterization and Assessment of Native Lactic Acid Bacteria from Broiler Intestines for Potential Probiotic Properties

Probiotics are the most promising alternative to antibiotics for improving animal production and controlling pathogenic infections, while strains derived from natural hosts are considered highly desirable due to their good adaptation to the gastrointestinal tract. The aim of this study was to screen Lactobacillus with broad-spectrum antibacterial activity from broilers fed an antibiotic-free diet and evaluate their potential as poultry probiotics. A total of 44 lactic acid bacteria (LAB) strains were isolated from the intestines of healthy broilers, among which 3 strains exhibited outstanding antimicrobial activity and were subsequently identified through 16S rRNA sequencing as Enterococcus faecium L8, Lactiplantibacillus plantarum L10, and Limosilactobacillus reuteri H11. These three isolates demonstrated potent bacteriostatic activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella cholerae, with inhibition zones ranging from 15.67 ± 1.53 to 21.33 ± 0.58 mm. The selected LAB strains exhibited high tolerance to acid and bile salts, with L. reuteri H11 displaying the highest survival rate (ranging from 34.68% to 110.28%) after exposure to 0.3% (w/v) bile salts for 6 h or a low pH environment (pH 2, 2.5, and 3) for 3 h. Notably, L. reuteri H11 outperformed other strains in terms of hydrophobicity (84.31%), auto-aggregation (53.12%), and co-aggregation with E. coli ATCC 25922 (36.81%) and S. aureus ATCC 6538 (40.20%). In addition, the three LAB isolates were either fully or moderately susceptible to the tested antibiotics, except for strain L8, which resisted gentamycin and vancomycin. Consequently, these three LAB strains, especially L. reuteri H11, isolated from the intestines of broiler chickens, represent promising probiotic candidates that can be employed as feed additives to enhance production performance and control poultry pathogens.

Antioxidant and Antibacterial Activities of Nano-probiotics Versus Free Probiotics Against Gastrointestinal Pathogenic Bacteria

Antibiotic-resistant pathogenic bacteria and the oxidative stress related to their infections are dangerous health problems. Finding new safe, effective antibacterial and antioxidant agents is an urgent global need. Probiotics are a strong candidate for possible antibacterial and antioxidant agents. The delivery of these probiotics without any effect on gastrointestinal digestion is the most important point for their application. The encapsulation of the probiotics on nanoparticles or other supports is a well-known method for the safe delivery of the probiotics. Little information is known about the effect of the probiotic encapsulation on its antibacterial and antioxidant activity. The present study tried to investigate the effect of probiotic encapsulation on nano-chitosan on its antioxidant activity and antibacterial activity against some pathogenic bacteria. We encapsulated some known probiotic species on nano-chitosan and investigated the antibacterial activity of the nano-probiotics and free probiotics against gastrointestinal pathogenic bacteria. The antioxidant characters of the free and encapsulated probiotics were investigated in terms of DPPH radicle scavenging activity, ferric ion chelating activity, hydroxyl radicle scavenging activity, superoxide anion radicle scavenging activity, and anti-lipid peroxidation activity. Results showed the superiority of the encapsulated probiotics as antibacterial and antioxidant agents over the free ones. The encapsulation improved the antibacterial activity of Sporolactobacillus laevolacticus against Bacteroides fragilis by 134% compared to the free one. Also, significantly, the encapsulation increased the hydroxyl radicle scavenging activity of Enterococcus faecium by about 180% compared to the free one. Nano-chitosan encapsulation synergistically increased the antioxidant and antibacterial activity of the studied probiotics. This can be promising for controlling pathogenic bacteria.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01140-2.

Antioxidant Effects and Probiotic Properties of Latilactobacillus sakei MS103 Isolated from Sweet Pickled Garlic

Fermented vegetable-based foods, renowned for their unique flavors and human health benefits, contain probiotic organisms with reported in vitro antioxidative effects. This study investigates the probiotic properties of Latilactobacillus sakei MS103 (L. sakei MS103) and its antioxidant activities using an in vitro oxidative stress model based on the hydrogen peroxide (H2O2)-induced oxidative damage of RAW 264.7 cells. L. sakei MS103 exhibited tolerance to extreme conditions (bile salts, low pH, lysozyme, H2O2), antibiotic sensitivity, and auto-aggregation ability. Moreover, L. sakei MS103 co-aggregated with pathogenic Porphyromonas gingivalis cells, inhibited P. gingivalis-induced biofilm formation, and exhibited robust hydrophobic and electrostatic properties that enabled it to strongly bind to gingival epithelial cells and HT-29 cells for enhanced antioxidant effects. Additionally, L. sakei MS103 exhibited other antioxidant properties, including ion-chelating capability and the ability to effectively scavenge superoxide anion free radicals, hydroxyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid, and 2,2-diphenyl-1-picrylhydrazyl. Furthermore, the addition of live or heat-killed L. sakei MS103 cells to H2O2-exposed RAW 264.7 cells alleviated oxidative stress, as reflected by reduced malondialdehyde levels, increased glutathione levels, and the up-regulated expression of four antioxidant-related genes (gshR2, gshR4, Gpx, and npx). These findings highlight L. sakei MS103 as a potential probiotic capable of inhibiting activities of P. gingivalis pathogenic bacteria and mitigating oxidative stress.

Evaluation of cholesterol transformation abilities and probiotic properties of Bacteroides dorei YGMCC0564

Hypercholesterolemia, a risk factor for cardiovascular disease (CVD), often requires therapeutic agents with varying degrees of side effects. This has created a need for safe and natural alternatives such as medications or functional foods that can improve lipid metabolism and reduce cholesterol levels. In recent years, Next-generation probiotics (NGPs) have recently emerged as a potential solution, offering distinct mechanisms compared to traditional probiotics. Among the NGPs, Bacteroides, a dominant bacterial genus in the human gut, has gained significant attention due to its prevalence, ability to break down plant polysaccharides, and production of short-chain fatty acids (SCFAs). Recent evidence has demonstrated that Bacteroides effectively reduces cholesterol levels, prevents obesity, and lowers the risk of CVD. However, research on Bacteroides is currently limited to a few species, leaving rooms for exploration of the beneficial functions of different species in this genus. In this study, we isolated 66 Bacteroides strains, including 9 distinct species, from healthy adults' fecal samples. By comparing their ability to assimilate cholesterol, we found that the transformation ability was not specific to any particular species. Notably, Bacteroides dorei YGMCC0564 revealed superior cholesterol-lowering capabilities and bile salt hydrolase (BSH) activity in vitro, surpassing that of Lactobacillus GG (LGG). YGMCC0564 exhibited favorable probiotic characteristics, including high survival rate in vitro simulation of gastrointestinal digestion, excellent adhesion ability, susceptibility to antibiotics, absence of hemolysis or virulence genes, and substantial production of SCFAs. The strain also demonstrated remarkable bile salt deconjugation activities and upregulation of the BT_416 gene associated with cholesterol, providing insights into a possible molecular mechanism underlying its cholesterol-reducing activity. These findings establish YGMCC0564 as a promising NPG candidate for improving cardiovascular health.

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.

Metabolites Potentially Determine the High Antioxidant Properties of Limosilactobacillus fermentum U-21

Many kinds of Lactobacillus are common occupants of humans' digestive tract that support the preservation of a balanced microbial environment that benefits host health. In this study, the unique lactic acid bacterium strain Limosilactobacillus fermentum U-21, which was isolated from the feces of a healthy human, was examined for its metabolite profile in order to compare it to that of the strain L. fermentum 279, which does not have antioxidant (AO) capabilities. By using GC × GC-MS, the metabolite fingerprint of each strain was identified, and the data were then subjected to multivariate bioinformatics analysis. The L. fermentum U-21 strain has previously been shown to possess distinctive antioxidant properties in in vivo and in vitro studies, positioning it as a drug candidate for the treatment of Parkinsonism. The production of multiple distinct compounds is shown by the metabolite analysis, demonstrating the unique characteristics of the L. fermentum U-21 strain. According to reports, some of the L. fermentum U-21 metabolites found in this study have health-promoting properties. The GC × GC-MS-based metabolomic tests defined strain L. fermentum U-21 as a potential postbiotic with significant antioxidant potential.