Characterization of Functional, Safety, and Probiotic Properties of Enterococcus faecalis AG5 Isolated From Wistar Rat, Demonstrating Adherence to HCT 116 Cells and Gastrointestinal Survivability

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.

Analysis and Characterization of Lactobacillus paragasseri and Lacticaseibacillus paracasei: Two Probiotic Bacteria that Can Degrade Intestinal Oxalate in Hyperoxaluric Rats

In the present study, we characterized the probiotic properties of two commercially available bacterial strains, Lactobacillus paragasseri UBLG-36 and Lacticaseibacillus paracasei UBLPC-87, and evaluated their ability to degrade oxalate in vitro and in a hyperoxaluria-induced nephrolithiasis rat model. UBLG-36 harboring two oxalate catabolizing genes, oxalyl coenzyme A decarboxylase (oxc) and formyl coenzyme A transferase (frc), was previously shown to degrade oxalate in vitro effectively. Here, we show that UBLPC-87, lacking both oxc and frc, could still degrade oxalate in vitro. Both these strains harbored several potential putative probiotic genes that may have conferred them the ability to survive in low pH and 0.3% bile, resist antibiotic stress, show antagonistic activity against pathogenic bacteria, and adhere to epithelial cell surfaces. We further evaluated if UBLG-36 and UBLPC-87 could degrade oxalate in vivo and prevent hyperoxaluria-induced nephrolithiasis in rats. We observed that rats treated with 4.5% sodium oxalate (NaOx) developed hyperoxaluria and renal stones. However, when pre-treated with UBLG-36 or UBLPC-87 before administering 4.5% NaOx, the rats were protected against several pathophysiological manifestations of hyperoxaluria. Compared to the hyperoxaluric rats, the probiotic pre-treated rats showed reduced urinary excretion of oxalate and urea (p < 0.05), decreased serum blood urea nitrogen and creatinine (p < 0.05), alleviated stone formation and renal histological damage, and an overall decrease in renal tissue oxalate and calcium content (p < 0.05). Taken together, both UBLG-36 and UBLPC-87 are effective oxalate catabolizing probiotics capable of preventing hyperoxaluria and alleviating renal damage associated with nephrolithiasis.

Probiotic and Safety Properties Screening of Enterococcus faecalis from Healthy Chinese Infants

The aim of this study was to evaluate the probiotic characteristics and safety of seven Enterococcus faecalis isolates from fecal samples of healthy Chinese infants. We evaluated the isolates' tolerance to low pH, survival in bile salts and NaCl, adhesion ability, biofilm formation, antimicrobial activity, toxin gene distribution, hemolysis, gelatinase activity, antibiotic resistance, and virulence to Galleria mellonella. All strains survived at pH 5.0, in 7.0% NaCl, and in 3% bile salt. Adhesion to Caco-2 cells was above 10%. Strain A3-1 had higher adhesion ability toward mucin, collagen, and BSA in vitro, better antibacterial activity, and the strongest biofilm production. We detected seven virulence genes with a distribution of asa1 (100%), cylA (71.4%), esp (85.7%), hyl (14.3%), gelE (85.7%), ace (42.9%), and agg (71.4%). Although all strains were γ-hemolytic, none showed gelatinase activity based on physiological activity detection. All isolates were susceptible to benzylpenicillin, ampicillin, ciprofloxacin, levofloxacin, moxifloxacin, tigecycline, nitrofurantoin, linezolid, and vancomycin; they were not susceptible to erythromycin, quinupristin/dalofopine, and clindamycin. The virulence test of G. mellonella showed that, except for strains 106-1 and 113-1, the other strains had toxicity lower than 10%. Strain A3-1 may have the greatest potential to be developed as a probiotic.

Probiotic Enterococcus faecalis AG5 mitigated high fat diet induced obesity and produced propionic acid stimulated apoptosis in 3T3-L1 pre-adipocyte

AIMS

Probiotics and their metabolites (SCFA) can regulate energy homeostasis. The present study thus evaluates the synergistic effect of probiotic Enterococcus faecalis AG5 on HFD induced obesity and the role of propionic acid (PA) in apoptosis induction of 3T3-L1 pre-adipocyte.

METHODS

Male Wistar rats (n = 24) were used to develop an HFD induced obesity model for 24 weeks. The effect of the orally administered probiotic AG5 (18th-24th weeks, 1 × 10⁹ CFU/ml) was evaluated using physiological, biochemical, anthropometry, histopathological and serological analyses. Apoptosis in 3T3-L1 pre-adipocyte was assessed using flow cytometry, protein expression of PPARγ, 5-LOX, NF-κB, p-AKT, caspase 10 and detection of caspase 3/7 by Immunofluorescence confirmed the apoptosis induced by PA.

KEY FINDINGS

Probiotic AG5 significantly reduced body weight, BMI, serum cholesterol, triglycerides (p < 0.05) and improved HDL, insulin and leptin but lowered LDL and VLDL (p > 0.05). An inflammatory response was reduced as evident by TNF-α IHC. AG5 reduced adipocyte hypertrophy and fatty acid accumulation. Flow cytometry confirmed late apoptosis in PA-AG5 and standard PA treated 3T3-L1 cells. 5-LOX inhibition is associated with apoptosis induction, and increased caspase 1p 10 is related to cell death initiation. The study initially showed a low PPARγ activity inhibiting 5-LOX which may relate to adipose apoptosis. Finally caspase 3/7 detection using immunofluorescence proved the role of PA in adipocyte apoptosis.

SIGNIFICANCE

The present study is a novel approach towards obesity mitigation involving adipocyte apoptosis. The role of SCFA in adipocyte apoptosis is very limited which can prove to be novel therapeutic approach in the future.

Fermented Seeds ("Zgougou") from Aleppo Pine as a Novel Source of Potentially Probiotic Lactic Acid Bacteria

Microorganisms inhabiting fermented foods represent the main link between the consumption of this food and human health. Although some fermented food is a reservoir of potentially probiotic microorganisms, several foods are still unexplored. This study aimed at characterizing the probiotic potential of lactic acid bacteria isolated from zgougou, a fermented matrix consisting of a watery mixture of Aleppo pine's seeds. In vitro methods were used to characterize the safety, survival ability in typical conditions of the gastrointestinal tract, and adherence capacity to surfaces, antimicrobial, and antioxidant activities. Strains belonged to the Lactobacillus plantarum group and Enterococcus faecalis showed no DNase, hemolytic, and gelatinase activities. In addition, their susceptibility to most of the tested antibiotics, satisfied some of the safety prerequisites for their potential use as probiotics. All the strains tolerated low pH, gastrointestinal enzymes, and bile salts. They displayed a good antibacterial activity and antibiofilm formation against 10 reference bacterial pathogens, especially when used as a cell-free supernatant. Furthermore, the lactic acid bacteria (LAB) strains inhibited the growth of Aspergillus flavus and Aspergillus carbonarius. Finally, they had good antioxidant activity, although depending on the strain. Overall, the results of this work highlight that zgougou represents an important reservoir of potentially probiotic LAB. Obviously, future studies should be addressed to confirm the health benefits of the LAB strains.

Probiotic Enterococcus faecalis AG5 effectively assimilates cholesterol and produces fatty acids including propionate

Probiotics are known for their health-promoting abilities through the production of various metabolites, and also benefits are membrane associated. Probiotic Enterococcus faecalis AG5 has been previously assessed for its probiotic properties and this study further strengthens that claim. Strain AG5 was inoculated with 0.3% sodium glychocholate (glycine conjugated) and bile salt mixture for different time periods. The percentage assimilation of cholesterol ranged from 14% to 33.1% in the bile salt mixture, but was slightly higher, ranging from 16.55% to 53.1%, in sodium thioglycocholate alone. Similarly, the bile salt hydrolysis activity was measured in terms of cholic acid release at different intervals. The overall range of cholic acid released ranged from 70.4 to 479 µg/mL. Fatty acid production is also an important criterion for a probiotic selection and it was found that the strain produced several long-chain fatty acids (LCFA) such as tetradecanoic acid, hexadecanoic acid, octadecanoic acid and bis(6-methylheptyl) phthalate. Besides LCFA, AG5 produced short-chain fatty acids (SCFA) such as propionic acid, which was estimated comparing liquid chromatography and mass spectrometry with standard SCFA. Thus the ability of deconjugation of bile salt and SCFA production is a value-added property of probiotic AG5, with the promise of being beneficial for human health.

Lactic acid bacteria, Enterococcus faecalis Y17 and Pediococcus pentosaceus G11, improved growth performance, and immunity of mud crab (Scylla paramamosain)

Mud crabs (Scylla paramamosain), a commercially important cultured species in the southeastern region of China, is usually infected by Vibriosis or parasites, causing great economic losses in cultured farms. Previous studies have demonstrated that probiotics benefited in enhancing the immune response against invading pathogens in aquatic animals. In this study, the effects of dietary administration of lactic acid bacteria (LAB) (Enterococcus faecalis Y17 and Pediococcus pentosaceus G11) on growth performance and immune responses of mud crab were assessed. Both strains (Y17 and G11) showed an inhibitory activity against bacterial pathogens (Aeromonas hydrophila, Vibrio parahaemolyticus, Vibrio alginolyticus, Staphylococcus aureus, and β Streptococcus), and a wide pH tolerance range of 2-10. In vivo, mud crabs were fed a control diet and experimental diets supplemented with 10⁹ cfu g^-1 diet either Y17 or G11 for 6 weeks before subjecting to a challenge test with V. parahaemolyticus for 12 h. The probiotic-supplemented diets had significant effects on weight gain and specific growth rate during the feeding trial. Increased serum enzyme activities of phenoloxidase, lysozyme, and SOD were observed in the hemolymph of mud crab in Y17 and G11-supplemented groups compared to that in the controls (P < 0.01). The significantly up-regulated expression of gene CAT, LYS, proPO, and SOD could be seen in hepatopancreas in G11-supplemented groups. After the pathogenicity test, the survival rate of Y17 + and G11 + V. parahaemolyticus groups was 66.67% and 80.00%, respectively, compared with 53.33% for the control groups. Taken together, dietary supplementation of Y17 and G11 strains were beneficial in mud crab, which could increase growth performance, modulate immune system and protect the host against V. parahaemolyticus infection.

Antilisterial efficacy of Lactobacillus brevis MF179529 from cow: an in vivo evidence

Background

Listeria monocytogenes is an opportunistic foodborne pathogen that causes human Listeriosis and high mortality particularly in immunocompromised individuals. Pregnant women are more prone to L. monocytogenes infection resulting in abortions.

In the present study, antilisterial activity of Lactobacillus brevis (LB) MF179529, a probiotic bacterial strain, was investigated in a murine model.

Methods

Initially a pilot study was conducted to determine the dose of L. monocytogenes required to cause symptomatic listeriosis. In the main trial, mice were divided into 4 groups. Group I was kept as negative control, group II was exposed to L. monocytogenes and maintained as positive control. Group III was fed with L. brevis only, while group IV received L. brevis for 3 days prior to L. monocytogenes infection. A volume of 200 μl of L. monocytogenes ATCC 19115 and L. brevis MF179529 bacterial suspension corresponding to cell density of 10⁹CFU/ml were given to respective groups by intragastric route. Progress of infection was monitored for 7 days including general health scoring, listeria dispersion in organs, bacterial load in intestine and blood biochemistry were recorded on 3rd, 5th and 7th days post infection (dpi).

Results

Clinical listeriosis was induced by 10⁹CFU/ml of L. monocytogenes ATCC 19115 in mice.

Animals of group IV displayed minor signs of infection. L. brevis supplementation resulted in significant reduction in dispersion and propagation of L. monocytogenes in liver, spleen and intestine. L. brevis MF179529 consumption led to a significant elevation of number of lactic acid bacteria and reduction of total plate count, anaerobic count and coliform population in intestine. Moreover, total leukocyte and neutrophil counts of treated animals were similar to the negative control while positive control group displayed higher number. Safety evaluation of L. brevis was performed by monitoring general health, hematological and serological parameters of L. brevis fed and negative control group (group III and I). No significant difference in feed intake, body temperature, body weight and blood picture could be detected in L. brevis supplemented and control groups.

Conclusion

Our results indicate ameliorative role of L. brevis in L. monocytogenes infection and suggest that L. brevis could be used for prophylactic measure.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2444-5) contains supplementary material, which is available to authorized users.