Efficacy of Potentially Probiotic Fruit-Derived Lactobacillus fermentum, L. paracasei and L. plantarum to Remove Aflatoxin M1 In Vitro

This study evaluated the efficacy of potentially probiotic fruit-derived Lactobacillus isolates, namely, L. paracasei 108, L. plantarum 49, and L. fermentum 111, to remove aflatoxin M₁ (AFM₁) from a phosphate buffer solution (PBS; spiked with 0.15 µg/mL AFM₁). The efficacy of examined isolates (approximately 10⁹ cfu/mL) as viable and non-viable cells (heat-killed; 100 °C, 1 h) to remove AFM₁ was measured after 1 and 24 h at 37 °C. The recovery of AFM₁ bound to bacterial cells after washing with PBS was also evaluated. Levels of AFM₁ in PBS were measured with high-performance liquid chromatography. Viable and non-viable cells of all examined isolates were capable of removing AFM₁ in PBS with removal percentage values in the range of 73.9–80.0% and 72.9–78.7%, respectively. Viable and non-viable cells of all examined Lactobacillus isolates had similar abilities to remove AFM₁. Only L. paracasei 108 showed higher values of AFM₁ removal after 24 h for both viable and non-viable cells. Percentage values of recovered AFM₁ from viable and non-viable cells after washing were in the range of 13.4–60.6% and 10.9–47.9%, respectively. L. plantarum 49 showed the highest AFM₁ retention capacity after washing. L. paracasei 108, L. plantarum 49, and L. fermentum 111 could have potential application to reduce AFM₁ to safe levels in foods and feeds. The cell viability of examined isolates was not a pre-requisite for their capacity to remove and retain AFM₁.

Influence of two anti-fungal Lactobacillus fermentum-Saccharomyces cerevisiae co-cultures on cocoa bean fermentation and final bean quality

The growth of filamentous fungi during the spontaneous cocoa bean fermentation leads to inferior cocoa bean quality and poses a health risk for consumers due to the potential accumulation of mycotoxins. We recently developed anti-fungal cultures with the capacity to inhibit the growth of mycotoxigenic filamentous fungi on cocoa beans. However, it is not clear how these anti-fungal cultures affect the fermentation process and cocoa bean quality. For that, the anti-fungal co-cultures, Lactobacillus fermentum M017-Saccharomyces cerevisiae H290 (A) and Lb. fermentum 223-S. cerevisiae H290 (B), were applied to 180-kg box fermentations in Honduras in three time-independent replications each including a spontaneous control fermentation. The comparison of inoculated and spontaneous fermentation processes revealed that the co-cultures only marginally affected the fermentation process and cocoa bean quality. Microorganisms reached maximal levels of 6.2-7.6 log CFU/g of yeasts and acetic acid bacteria and 7.9-9.5 log CFU/g of lactic acid bacteria during all fermentations and led to maximal metabolite concentrations in bean cotyledons of 4-12 mg/g ethanol, 2-6 mg/g lactic acid and 6-14 mg/g acetic acid. The fermentation and drying processes resulted in 38-90 mg epicatechin equivalents/g in the cotyledons of dried beans. However, the co-cultures led to up to ten times higher mannitol levels in cotyledons of inoculated beans compared to beans during spontaneous fermentation, and caused a slower fermentation process, detectable as up to 8-12 °C lower temperatures in the centre of the fermenting pulp-bean mass and up to 22% lower proportions of well-fermented beans after drying. Co-culture B-with Lb. fermentum 223 -led to improved cocoa bean quality compared to co-culture A-with Lb. fermentum M017 -, i.e. cocoa beans with 0.5-1.9 mg/g less acetic acid, 4-17% higher shares of well-fermented beans and, on a scale from 0 to 10, to 0.2-0.6 units lower astringency, up to 1.1 units lower off-flavours, and 0.2-0.9 units higher cocoa notes. Therefore, the anti-fungal co-culture B is recommended for future applications and its capacity to limit fungal growth and mycotoxin production during industrial-scale cocoa bean fermentation should be investigated in further studies.

Protective effects of Lactobacillus fermentum U-21 against paraquat-induced oxidative stress in Caenorhabditis elegans and mouse models

The aims of this work were to identify in vivo manifestations of antioxidant activity of Lactobacillus strains isolated from healthy human biotopes and to show the possibility of protective action of the selected strain on the model of oxidative stress induced by paraquat in the model of early Parkinson's disease (PD) in mice. We studied the protective effects of 14 Lactobacillus strains belonging to five species on the lifespan of the soil nematode Caenorhabditis elegans experiencing oxidative stress induced by paraquat. The Lactobacillus strains used in this study were selected previously based on their ability to reduce oxidative stress in vitro. One of the strains that showed promising results on C. elegans was tested in a mouse model of PD in which C57/BL6 mice were injected regularly with paraquat. We assessed the state of their internal organs, the preservation of dopaminergic neurons in the substantia nigra as well as their motor coordination. The positive impact of Lactobacillus fermentum U-21 strain supplementation on paraquat treated animals was observed. L. fermentum U-21 strain reduced the toxicity of paraquat in C. elegans model: the lifespan of the soil nematode C. elegans was extended by 25%. L. fermentum U-21 protected the mice against anatomical and behavioral changes typical of PD: there were no changes in the coordination of movement and the preservation of dopaminergic neurons in the brain. Life span of the nematode C. elegans pre-grown on a lawn of E. coli OP50 + Lactobacillus under oxidative stress conditions; the concentration of the oxidizing agent paraquat in the S medium was 50 mmol l^-1.

Hypnotic Effects of Lactobacillus fermentum PS150TM on Pentobarbital-Induced Sleep in Mice

The bidirectional communication between the gastrointestinal tract and the central nervous system appears to be functionally linked to the intestinal microbiome, namely the microbiome-gut-brain axis (MGBA). Probiotics with health benefits on psychiatric or neurological illnesses are generally called psychobiotics, and some of them may also be able to improve sleep by targeting the MGBA. This study aimed to investigate the effects of a psychobiotic strain, Lactobacillus fermentum PS150TM (PS150TM), on sleep improvement by using a pentobarbital-induced sleep mouse model. Compared with the vehicle control group, the oral administration of PS150TM, but not the other L. fermentum strains, significantly decreased the sleep latency and increased the sleep duration of mice, suggesting strain-specific sleep-improving effects of PS150TM. Moreover, the ingestion of diphenhydramine, an antihistamine used to treat insomnia, as a drug control group, only increased the sleep duration of mice. We also found that the sleep-improving effects of PS150TM are time- and dose-dependent. Furthermore, the oral administration of PS150TM could attenuate a caffeine-induced sleep disturbance in mice, and PS150TM appeared to increase the expression of the gene encoding the adenosine 1 receptor in the hypothalamus of mice, as assessed by quantitative real-time polymerase chain reaction. Taken together, our results present a potential application of PS150TM as a dietary supplement for sleep improvement.

Encapsulation of Lactobacillus fermentum K73 by Refractance Window drying

The purpose of this work was to model the survival of the microorganism and the kinetics of drying during the encapsulation of Lactobacillus fermentum K73 by Refractance Window drying. A whey culture medium with and without addition of maltodextrin were used as encapsulation matrices. The microorganism with the encapsulation matrices was dried at three water temperatures (333, 343 and 353 K) until reaching balanced moisture. Microorganism survival and thin layer drying kinetics were studied by using mathematical models. Results showed that modified Gompertz model and Midilli model described the survival of the microorganism and the drying kinetics, respectively. The most favorable process conditions found with the mathematical modelling were a drying time of 2460 s, at a temperature of 353 K. At these conditions, a product with 9.1 Log CFU/g and a final humidity of 10% [wet basis] using the culture medium as encapsulation matrix was obtained. The result shows that Refractance Window can be applied to encapsulate the microorganism probiotic with a proper survival of the microorganism.

Lactobacillus species increase the survival of Galleria mellonella infected with Candida albicans and non-albicans Candida clinical isolates

Investigation into new therapeutic strategies, such as the use of bacterial isolates with probiotic characteristics, has increased in importance due to the high incidence of Candida albicans and non-albicans Candida infections. This study evaluates Lactobacillus paracasei, Lactobacillus fermentum and Lactobacillus rhamnosus strains as prophylactic and therapeutic agents against infection caused by Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis in a Galleria mellonella model. Prophylactic treatment provided greater benefits during Candida spp. infection, increasing G. mellonella survival, compared to therapeutic treatment. This study demonstrated that the different Lactobacillus species are potent prophylactic agents of Candida species infection.

Effect of Milk Fermented with Lactobacillus fermentum on the Inflammatory Response in Mice

Currently, the effect of fermented milk on the T-helper 17 response in inflammatory bowel diseases (IBDs) is unknown. The aim of the present study was to evaluate the effect of milks fermented with Lactobacillus fermentum on the Th1/Th17 response in a murine model of mild IBD. Exopolysaccharide (EPS), lactic acid (LA), and total protein (TP) contents and bacterial concentration were determined. Male C57Bl/6 mice intragastrically received either raw (FM) or pasteurized (PFM) fermented milk before and during a dextran sulfate infusion protocol. Blood, spleen, and colon samples were collected at Weeks 6 and 10. IL-6, IL-10, and TNFα were determined in serum, and IL-17, IL-23, and IFNγ were determined in intestinal mucosa and serum. The FM groups did not differ in cell concentration, LA, or TP content (p > 0.05); FM-J28 had the highest EPS content. Spleen weight and colon length did not differ among the FM groups (p > 0.05). In the FM-J20 and PFM-J20 groups, IL-17 and IFNγ decreased, and the IL-10 concentration was enhanced (p < 0.05) at Week 6. IL-6, TNFα, IL-23, and IFNγ did not differ in serum and mucosa (p > 0.05), and IL-17 was lowest in FM-J28 and FM-J20. Therefore, FM appears to potentially play a role in decreasing the Th17 response. However, further studies are needed to elucidate the FM-mediated anti-inflammatory mechanisms in IBD.

Hepatoprotective Effects of Lactobacillus on Carbon Tetrachloride-Induced Acute Liver Injury in Mice

The aim of this study was to investigate and compare the effects of heat-killed and live Lactobacillus on carbon tetrachloride (CCl₄)-induced acute liver injury mice. The indexes evaluated included liver pathological changes, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) in the serum, related gene expression (IL-1β, TNF-α, Bcl-2, and Bax), and related proteins levels (Bax, Bcl-2, Caspase 3, and NF-κB p65). Compared with the model group, the results indicated that the levels of ALT, AST, and MDA in the serum, the expression levels of IL-1β, TNF-α, and Bax, and the protein levels of Bax, Caspase 3, and NF-κB p65 significantly decreased, and the pathologic damage degree all significantly reduced after live Lactobacillus fermentum (L-LF) and live Lactobacillus plantarum (L-LP) treatment. Additionally, the levels of SOD and GSH in the serum, the gene expression of Bcl-2, and the protein level of Bcl-2 significantly increased after L-LF and L-LP treatment. Although HK-LF and HK-LP could also have obvious regulating effects on some of the evaluated indexes (ALT, AST, the expression levels of TNF-α and Bax, and the protein level of Bcl-2) and play an important role in weakening liver damage, the regulating effects of L-LF or L-LP on these indexes were all better compared with the corresponding heat-killed Lactobacillus fermentum (HK-LF) and heat-killed Lactobacillus plantarum (HK-LP). Therefore, these results suggested that LF and LP have an important role in liver disease.

Prevent Effects of Lactobacillus Fermentum HY01 on Dextran Sulfate Sodium-Induced Colitis in Mice

The aim of this study is to assess the preventive effects of Lactobacillus fermentum HY01 (LF-HY01) to dextran sulfate sodium induced-colitis. We observed the ratio of colon weight to its length, colon pathological changes, and the concentrations of pro-inflammatory factors (IFN-γ, IL-12, TNFα, and IL-6) in serum. We also took account of the protein levels of IκBα, NF-κB p65, iNOS, and COX-2, and we measured the best effects of different doses of Lactobacillus fermentum HY01 (low dose group was 10⁹ CFU/kg·bw, high dose group was 10¹⁰ CFU/kg·bw) on dextran sulfate sodium-induced colitis mice. The results were remarkable, suggesting that Lactobacillus fermentum HY01 had significant preventive effects in dextran sulfate sodium induced-colitis; simultaneously, the high dose group showed the best results among other groups. It can effectively alleviate the shortened colon length, reduce the ratio of colon weight to its length, reduce edema, inflammatory cells infiltration, and colon mucosa injury, and play an important role in the down-regulation of concentrations of pro-inflammatory factors (IFN-γ, IL-12, TNFα, and IL-6). Above all, Lactobacillus fermentum HY01 shows promising prevention for IκBα degradation, inhibition of NF-κB p65 phosphorylation cascades, and decreases the protein levels of iNOS and COX-2 as well.

In vitro and in vivo antagonistic activity of new probiotic culture against Clostridium difficile and Clostridium perfringens

BACKGROUND

Genus Clostridium accompanies more than 200 known species and at least 30 among them are associated with human and animal diseases. At the moment, the treatment of clostridial infections is based on use of antibiotics. However, due to the European ban on the use of antibiotics in livestock production, novel therapeutic strategies for treatment of these hardly curable infections have been evaluated. Hence, in this study the antimicrobial effect of newly designed probiotic culture consisted of natural isolates Lactobacillus helveticus BGRA43, Lactobacillus fermentum BGHI14 and Streptococcus thermophilus BGVLJ1-44 against Clostridium difficile and Clostridium perfringens was analyzed.

RESULTS

The probiotic culture showed strong in vitro antimicrobial effect on C. difficile (human clinical isolate). In addition, individual strains and the probiotic combination exhibited immunomodulatory activity. The probiotic combination significantly increased the proliferation of GALT lymphocytes. At the other hand, none of the bacterial treatments (individual strains and the combination) induced the production of proinflammatory cytokines IL-6 and IL-1β by intestinal epithelial cells, Caco-2. Interestingly, Caco-2 cells exposed to the probiotic combination produced significantly elevated amount of TGFβ pointing to potential protecting effect of the probiotic. In addition, the results of field trial on spontaneously infected goats revealed reduction of C. perfringens in goats (below the detection threshold) after the probiotic treatment.

CONCLUSIONS

The results of this study indicated that the novel probiotic deserves to be further investigated as a promising antimicrobial agent against C. difficile and C. perfringens.

Impact of Lactobacillus fermentum and dairy lipids in the maternal diet on the fatty acid composition of pups' brain and peripheral tissues

The aim of the study was to determine the effect of maternal diets administered since day 1 of gestation and containing dairy lipids or vegetable oils differing in the supply of n-3 polyunsaturated fatty acids (n-3 PUFAs) (equilibrated or deficient) and of Lactobacillus fermentum (L. fermentum) on the docosahexaenoic acid (DHA) accretion in the pups at postnatal day 14 in the prefrontal cortex (PFC) and hippocampus (HC) for brain structures and in the liver and adipose tissue for peripheral tissues. Maternal milk fatty acid composition was also assessed by analyzing the fatty acid composition of the gastric content of the pups. DHA was higher in mice supplemented with L. fermentum than in mice in the deficient group in HC and PFC and also in liver and adipose tissue. This increase could be linked to the slight but significant increase in C18:3n-3 in the maternal milk. This proportion was comparable in the dairy lipid group for which the brain DHA level was the highest. L. fermentum may have a key role in the protection of the brain during the perinatal period via the neuronal accretion of n-3 PUFAs, especially during n-3 PUFA deficiency.

Probiotic Lactobacillus fermentum UCO-979C biofilm formation on AGS and Caco-2 cells and Helicobacter pylori inhibition

The ability of the human isolate Lactobacillus fermentum UCO-979C to form biofilm and synthesize exopolysaccharide on abiotic and biotic models is described. These properties were compared with the well-known Lactobacillus casei Shirota to better understand their anti-Helicobacter pylori probiotic activities. The two strains of lactobacilli synthesized exopolysaccharide as detected by the Dubois method and formed biofilm on abiotic and biotic surfaces visualized by crystal violet staining and scanning electron microscopy. Concomitantly, these strains inhibited H. pylori urease activity by up to 80.4% (strain UCO-979C) and 66.8% (strain Shirota) in gastric adenocarcinoma (AGS) cells, but the two species showed equal levels of inhibition (~84%) in colorectal adenocarcinoma (Caco-2) cells. The results suggest that L. fermentum UCO-979C has probiotic potential against H. pylori infections. However, further analyses are needed to explain the increased activity observed against the pathogen in AGS cells as compared to L. casei Shirota.

Hypoglycemic and hypolipidemic effects of Lactobacillus fermentum, fruit extracts of Syzygium cumini and Momordica charantia on diabetes induced mice

A lot of treatment strategies available for diabetes but its complications are still a medical problem around the globe. It demands to find out some alternative therapeutic measures. In order to investigate the anti-diabetic potential of probiotics and natural extracts, this study was designed. Accordingly, a local source of yogurt probiotic strain Lactobacillus fermentum was isolated and characterized that showed its probiotic properties. Besides this, natural extracts of plants fruits like java plum (Syzygium cumini) and bitter gourd (M. charantia) were made. Lactobacillus fermentum and the extracts were administered individually as well as in combination to diabetes induced mice. Different parameters like body weight, blood glucose level and lipid profile including total cholesterol, HDL & LDL were analyzed before and after treatment. The results showed that Lactobacillus fermentum and natural extracts have hypoglycemic as well hypolipidemic activity against diabetic mice. This study can further investigated to screen potential compounds from these extracts to control the glucose and the lipid levels in diabetic patients.

Lactobacillus fermentum AGR1487 cell surface structures and supernatant increase paracellular permeability through different pathways

Lactobacillus fermentum is commonly found in food products, and some strains are known to have beneficial effects on human health. However, our previous research indicated that L. fermentum AGR1487 decreases in vitro intestinal barrier integrity. The hypothesis was that cell surface structures of AGR1487 are responsible for the observed in vitro effect. AGR1487 was compared to another human oral L. fermentum strain, AGR1485, which does not cause the same effect. The examination of phenotypic traits associated with the composition of cell surface structures showed that compared to AGR1485, AGR1487 had a smaller genome, utilized different sugars, and had greater tolerance to acid and bile. The effect of the two strains on intestinal barrier integrity was determined using two independent measures of paracellular permeability of the intestinal epithelial Caco-2 cell line. The transepithelial electrical resistance (TEER) assay specifically measures ion permeability, whereas the mannitol flux assay measures the passage of uncharged molecules. Both live and UV-inactivated AGR1487 decreased TEER across Caco-2 cells implicating the cell surfaces structures in the effect. However, only live AGR1487, and not UV-inactivated AGR1487, increased the rate of passage of mannitol, implying that a secreted component(s) is responsible for this effect. These differences in barrier integrity results are likely due to the TEER and mannitol flux assays measuring different characteristics of the epithelial barrier, and therefore imply that there are multiple mechanisms involved in the effect of AGR1487 on barrier integrity.

Streptococcus mitis induces conversion of Helicobacter pylori to coccoid cells during co-culture in vitro

Helicobacter pylori (H. pylori) is a major gastric pathogen that has been associated with humans for more than 60,000 years. H. pylori causes different gastric diseases including dyspepsia, ulcers and gastric cancers. Disease development depends on several factors including the infecting H. pylori strain, environmental and host factors. Another factor that might influence H. pylori colonization and diseases is the gastric microbiota that was overlooked for long because of the belief that human stomach was a hostile environment that cannot support microbial life. Once established, H. pylori mainly resides in the gastric mucosa and interacts with the resident bacteria. How these interactions impact on H. pylori-caused diseases has been poorly studied in human. In this study, we analyzed the interactions between H. pylori and two bacteria, Streptococcus mitis and Lactobacillus fermentum that are present in the stomach of both healthy and gastric disease human patients. We have found that S. mitis produced and released one or more diffusible factors that induce growth inhibition and coccoid conversion of H. pylori cells. In contrast, both H. pylori and L. fermentum secreted factors that promote survival of S. mitis during the stationary phase of growth. Using a metabolomics approach, we identified compounds that might be responsible for the conversion of H. pylori from spiral to coccoid cells. This study provide evidences that gastric bacteria influences H. pylori physiology and therefore possibly the diseases this bacterium causes.

An in vitro study of the effect of probiotics, prebiotics and synbiotics on the elderly faecal microbiota

The use of dietary intervention in the elderly in order to beneficially modulate their gut microbiota has not been extensively studied. The influence of two probiotics (Bifidobacterium longum and Lactobacillus fermentum) and two prebiotics [isomaltooligosaccharides (IMO) and short-chain fructooligosaccharides (FOS)], individually and in synbiotic combinations (B. longum with IMO, L. fermentum with FOS) on the gut microbiota of elderly individuals was investigated using faecal batch cultures and three-stage continuous culture systems. Population changes of major bacterial groups were enumerated using fluorescent in situ hybridisation (FISH). B. longum and IMO alone significantly increased the Bifidobacterium count after 5 and 10 h of fermentation and their synbiotic combination significantly decreased the Bacteroides count after 5 h of fermentation. L. fermentum and FOS alone significantly increased the Bifidobacterium count after 10 h and 5, 10 and 24 h of fermentation respectively. B. longum with IMO as well as B. longum and IMO alone significantly increased acetic acid concentration during the fermentation in batch cultures. In the three-stage continuous culture systems, both synbiotic combinations increased the Bifidobacterium and Lactobacillus count in the third vessel representing the distal colon. In addition, the synbiotic combination of L. fermentum with scFOS resulted in a significant increase in the concentration of acetic acid. The results show that the elderly gut microbiota can be modulated in vitro with the appropriate pro-, pre- and synbiotics.

The antibacterial and anti-biofouling performance of biogenic silver nanoparticles by Lactobacillus fermentum

Biofouling is a major challenge in the water industry and public health. Silver nanoparticles (AgNPs) have excellent antimicrobial properties and are considered to be a promising anti-biofouling agent. A modified method was used to produce small sized and well-dispersed biogenic silver nanoparticles with a mean size of ~6 nm (Bio-Ag0-6) using Lactobacillus fermentum. The morphology, size distribution, zeta potential and oxidation state of the silver were systematically characterized. Determination of minimal inhibitory and bactericidal concentration results revealed that biogenic silver Bio-Ag(0-6) can effectively suppress the growth of the test bacteria. Additionally, the inhibition effects of Bio-Ag(0-6) on biofilm formation and on established biofilms were evaluated using P. aeruginosa (ATCC 27853) as the model bacterium. The results from microtiter plates and confocal laser scanning microscopy demonstrated that Bio-Ag(0-6) not only exhibited excellent antibacterial performance but also could control biofilm formation and induce detachment of the bulk of P. aeruginosa biofilms leaving a small residual matrix.

[Characterization of a probiotic Lactobacillus strain isolated from oral cavity]

OBJECTIVE

From oral cavity we isolated and characterized probiotic lactobacilli that could probability be applied to therapy and prevention of oral diseases.

METHODS

Lactobacillus strains were isolated by plating the saliva and dental plaque of healthy donors on selective medium. Then the target strains were tested for inhibiting the growth of a Streptococcus mutans strain belonging to cariogenic pathogen species. Other properties such as production of extracellular polysaccharide and resistance to the antibacterial substances were also investigated.

RESULTS

Lactobacillus fermentum Y29, a strain with antimicrobial activity against Streptococcus mutans, was obtained from dental plaque. This strain was an extracellular polysaccharide producer, which corresponds to its aggregation ability. Moreover, L. fermentum Y29 showed resistance to 1.0 mg/mL lysozyme and 140 microg/g hydrogen peroxide that may guarantee its persistence in the complex oral niche.

CONCLUSION

Probiotic properties were characterized of an oral isolate L. fermentum Y29, which provided a possibility for its application in prevention and treatment of oral diseases.

Characterisation of Lactobacillus fermentum SM-7 isolated from koumiss, a potential probiotic bacterium with cholesterol-lowering effects

BACKGROUND

Lactic acid bacteria (LAB) have been demonstrated to have cholesterol-reducing effects in many studies.

RESULTS

Lactobacillus fermentum SM-7 screened from ten LAB strains isolated from koumiss, a fermented milk drink, reduced cholesterol by 66.8%. It also showed acid and bile tolerance as well as antimicrobial activity against pathogenic Escherchia coli and Staphylococcus aureus. Lactobacillus fermentum SM-7 cells assimilated 61.5% and co-precipitated and absorbed 38.5% of the cholesterol in the media. Co-precipitation of cholesterol with cholic acid increased rapidly at pH levels below 6. In vivo experiments using L. fermentum SM-7 on artificially induced hyperlipidaemial ICR mice significantly decreased serum total cholesterol and total triglyceride levels, low-density lipoprotein cholesterol concentrations and atherogenic index (P < 0.01), while serum high-density lipoprotein cholesterol concentrations did not increase significantly (P > 0.05). The body weight and liver weight/body weight ratio of SM-7 groups were lower than those of mice on a high-cholesterol diet that were not given lactobacilli. There was no bacterial translocation in the liver, spleen or kidney of experimental mice.

CONCLUSION

The results suggested that L. fermentum SM-7 is a potential probiotic bacterium with cholesterol-lowering effects.

[Disorganization of biofilms of clinical strains of staphylococci by metabolites of lactobacilli]

AIM

To study morpho-physiologic characteristics of clinical biofilm-forming strains of Staphylococcus aureus and S. epidermidis suppressed by metabolites of lactobacilli, which produce bacteriocin-like substances.

MATERIALS AND METHODS

Two clinical biofilm-forming strains of S. aureus and one strain of S. epidermidis were used. Strains Lactobacillus plantarum L3 and L. fermentum 97 were used as producers of bactericidal metabolites. Ability of staphylococci to form biofilms was studied after their growth during 18 h at 37 degrees C in beef-extract broth with subsequent registration of biofilms attached to walls and bottom of polystyrene plate and stained by 0.1% alcohol solution of crystal violet. Ultrastructural changes in target cells were visualized by electron microscopy.

RESULTS

Suppressive effect of lactobacilli metabolites on formation of biofilms by staphylococci was established. Ultrasructural changes, which characterize disorganization of vital processes such as mitosis, synthesis of DNA and peptidoglycan layer, were revealed in target cells. Formation and detachment of peptidoglycan globules from cell wall surface externally were noted.

CONCLUSION

Metabolites of lactobacilli are able to suppress formation of biofilms and induce ultrastructural changes in S. aureus and S. epidermidis, which lead to their destruction.

Preparation and in vitro analysis of microencapsulated live Lactobacillus fermentum 11976 for augmentation of feruloyl esterase in the gastrointestinal tract

FA (ferulic acid) is a well-known phenolic phytochemical present in plant cell walls. Various studies have indicated that FA has many physiological functions in the prevention of chronic disease. It has been shown to play an important chemoprotective role in degenerative diseases. FA also shows strong antioxidant and nitrite-scavenging potential and anticarcinogenic and antiinflammatory properties. The in vivo physiological importance of FA depends on its availability for absorption. Dietary fibre-bound FA is partially released by gut micro-organisms; however, the concentration of the released FA is too low to act as a chemopreventive agent. Therefore it is important to augment the bioavailability of FA to appreciate more fully its real physiological effect. This paper evaluates the suitability of the alginate-poly(L-lysine)-alginate microcapsules for oral delivery of live feruloyl esterase-producing Lactobacillus fermentum 11976 cells, in vitro, by using a dynamic simulated human GI (gastrointestinal) model. The present study shows that microencapsulated L. fermentum 11976 cells can efficiently break down a FA-containing substrate, and establishes the biotechnological basis for their use in supplementing the bioavailability of dietary FA in the intestine.

Image analysis for monitoring the barley tempeh fermentation process

AIMS

To develop a fast, accurate, objective and nondestructive method for monitoring barley tempeh fermentation.

METHODS AND RESULTS

Barley tempeh is a food made from pearled barley grains fermented with Rhizopus oligosporus. Rhizopus oligosporus growth is important for tempeh quality, but quantifying its growth is difficult and laborious. A system was developed for analysing digital images of fermentation stages using two image processing methods. The first employed statistical measures sensitive to image colour and surface structure, and these statistical measures were highly correlated (r=0.92, n=75, P<0.001) with ergosterol content of tempeh fermented with R. oligosporus and lactic acid bacteria (LAB). In the second method, an image-processing algorithm optimized to changes in images of final tempeh products was developed to measure number of visible barley grains. A threshold of 5 visible grains per Petri dish indicated complete tempeh fermentation. When images of tempeh cakes fermented with different inoculation levels of R. oligosporus were analysed the results from the two image processing methods were in good agreement.

CONCLUSION

Image processing proved suitable for monitoring barley tempeh fermentation. The method avoids sampling, is nonintrusive, and only requires a digital camera with good resolution and image analysis software.

SIGNIFICANCE AND IMPACT OF THE STUDY

The system provides a rapid visualization of tempeh product maturation and qualities during fermentation. Automated online monitoring of tempeh fermentation by coupling automated image acquisition with image processing software could be further developed for process control.

Two Lactobacillus strains, isolated from breast milk, differently modulate the immune response

AIMS

The ability of two different Lactobacillus strains (Lactobacillus salivarius CECT5713 and Lactobacillus fermentum CECT5716), isolated from human breast milk, to modulate the immune response was examined.

METHODS AND RESULTS

In rodent bone-marrow-derived macrophages (BMDM), the presence of Lact. fermentum CECT5716 induced pro-inflammatory cytokines, in contrast to the activation of IL-10 induced by Lact. salivarius CECT5713. Although both strains reduced the lipopolysaccharide (LPS)-induced inflammatory response in BMDM, the effect of Lact. salivarius CECT5713 was more efficient, probably because of the production of higher amounts of IL-10 cytokine. In vivo assays in mice showed similar results; the consumption of Lact. fermentum CECT5716 enhanced the production of Th1 cytokines by spleen cells and increased the IgA concentration in faeces. However, the consumption of Lact. salivarius CECT5713 induced IL-10 production by spleen cells.

CONCLUSION

Therefore, in general, the effect of Lact. fermentum CECT5716 is immunostimulatory in contrast to the anti-inflammatory effect of Lact. salivarius CECT5713.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study show that two Lactobacillus strains isolated from breast milk can exert different and even opposing effects on immune response demonstrating the specificity of each strain.

Effect of ethanol rinse, Lactobacillus fermentum inoculation, and modified atmosphere on ground chicken meat quality

Ground chicken breast meat was prepared using combinations of the following treatments: ethanol rinse before grinding, inoculation with Lactobacillus fermentum after grinding, and modified atmosphere packaging in either 90% O(2) and 10% CO(2) or 90% N(2) and 10% CO(2). Control treatments included water rinse and noninoculation with L. fermentum. Packaged meat was refrigerated and sampled for various shelf-life quality indices on d 0, 3, and 6. The inoculation with L. fermentum had little or no effect on ground meat shelf life. The ethanol-rinsed meat had lower off-odor scores and lower microbial growth compared to nonethanol rinsed meat. The high-N(2) atmosphere maintained meat color better than the high-O(2) packaging, but there was no effect on microbial growth. The combination of ethanol rinsing and high-N(2) packaging extended ground chicken quality compared with meat rinsed in water and packaged in high O(2).

A Probiotic, Lactobacillus fermentum ME-3, Has Antioxidative Capacity in Soft Cheese Spreads with Different Fats

Our aim was to develop a prototype of a functional spread cheese containing both a specific probiotic and n-3 fatty acids and to analyze the viability of the probiotic and stability of n-3 fatty acids during 4 wk of shelf life. Lactobacillus fermentum ME-3 (Lf ME-3) isolated from a healthy Estonian child has been shown to have probiotic and antioxidative properties in several recent studies. In the current study this promising bacterial strain was combined with vegetable oils rich in nutritionally important alpha-linolenic acid and with unflavored cheese to obtain soft cheese spreads with different fat contents. Lactobacillus fermentum ME-3 survived well in all cheeses although the viable count did not increase during 4 wk of storage. The fatty acid composition of cheese triacylglycerols remained stable, whereas the profile of volatile compounds changed: hexanal and pentanal disappeared and the proportion of some alcohols increased. The changes in the profile of volatile compounds show the reductive power of Lf ME-3. A functional spread cheese containing n-3 fatty acids can be prepared with the probiotic Lactobacillus fermentum ME-3 strain leading to a reduced need for chemical anti-oxidants.

Effects of bacterial colonization on the porcine intestinal proteome

The gastrointestinal tract harbors a complex community of bacteria, of which many may be beneficial. Studies of germ-free animal models have shown that the gastrointestinal microbiota not only assists in making nutrients available for the host but also contributes to intestinal health and development. We studied small intestinal protein expression patterns in gnotobiotic pigs maintained germ-free, or monoassociated with either Lactobacillus fermentum or non-pathogenic Escherichia coli. A common reference design in combination with labeling with stable isobaric tags allowed the individual comparison of 12 animals. Our results showed that bacterial colonization differentially affected mechanisms such as proteolysis, epithelial proliferation, and lipid metabolism, which is in good agreement with previous studies of other germ-free animal models. We have also found that E. coli has a profound effect on actin remodeling and intestinal proliferation, which may be related to stimulated migration and turnover of enterocytes. Regulations related to L. fermentum colonization involved individual markers for immunoregulatory mechanisms.

Different probiotic properties for Lactobacillus fermentum strains isolated from swine and poultry

Systematic procedures were used to evaluate the probiotic properties of Lactobacillus fermentum (L. fermentum) strains isolated from swine and poultry. The major properties included their capabilities to adhere to the intestinal epithelium of swine and poultry, the inhibition on pathogenic bacteria, and their tolerance to the gastric juice and bile salts. Results showed that L. fermentum strains from poultry digestive tract showed better adherence to the swine intestine and chicken crop epithelial cells as compared to those strains from the swine origin. In addition, six strains from poultry and one strain from swine showed adhesion specificity to their own intestinal epithelium. Four poultry isolates and one swine isolate were able to adhere to the epithelial cells from both swine and chicken. For gastric juice and bile tolerance, most of the strains isolated from swine or poultry were acid tolerant but less strains were bile intolerant. The spent culture supernatant (SCS) of these L. fermentum strains showed antagonistic effect against the indicator bacteria, such as Escherichia coli, Salmonella spp., Shigella sonnei and some enterotoxigenic Staphylococcus aureus. From the above studies, some L. fermentum strains isolated from poultry were found to have the probiotic properties required for use in animal feed supplement. This study suggested that poultry digestive tract may serve as potential source for the isolation of probiotic lactic acid bacteria.

Lactobacillus fermentum BR11, a potential new probiotic, alleviates symptoms of colitis induced by dextran sulfate sodium (DSS) in rats

Current treatments for inflammatory bowel disease (IBD) are relatively ineffective. Recently, probiotics have emerged as a potential treatment modality for numerous gastrointestinal disorders, including IBD. Few probiotics, however, have undergone appropriate preclinical screening in vivo. The current study compared the effects of four candidate probiotics on development of dextran sulfate sodium (DSS)-induced colitis in rats. Sprague Dawley rats were gavaged 1 mL of the potential probiotic (1 x 10(10) CFU/mL), or vehicle, twice daily for 14 days. Strains tested were Lactobacillus rhamnosus GG (LGG), Streptococcus thermophilus TH-4 (TH-4), Bifidobacterium lactis Bb12 (Bb12) and Lactobacillus fermentum BR11 (BR11). Colitis was induced from day 7 to 14 via administration of 2% DSS in drinking water. Disease activity index (DAI) was monitored daily until rats were killed at day 14. DAI decreased in DSS+Bb12 and DSS+BR11 compared to DSS+Vehicle. Colon length increased in DSS+BR11 (10%) and DSS+LGG (10%) compared to DSS+Vehicle. DSS+Bb12 and DSS+BR11 prevented the distal colon crypt hyperplasia evident in DSS+Vehicle, DSS+LGG and DSS+TH-4. BR11 was most effective at reducing colitic symptoms. Bb12 had minimal effects, whilst TH-4 did not prevent DSS-colitis and LGG actually exacerbated some indicators of colitis. Further studies into the potential benefits of L. fermentum BR11 are indicated.

Lactobacillus fermentum attenuates the proinflammatory effect of Yersinia enterocolitica on human epithelial cells

BACKGROUND

Lactobacilli represent a major component of the human microbiota. In this study we investigated whether and how Lactobacillus fermentum inhibits the proinflammatory responses of human epithelial cells on Yersinia enterocolitica infection.

METHODS

Human epithelial cells were exposed to Y. enterocolitica pYV(-) or L. fermentum or to both strains, combinations of heat-killed L. fermentum or supernatant of L. fermentum cultures and Y. enterocolitica. The modulation of Y. enterocolitica induced IL-8 levels in the culture supernatants was determined and activation of Rac, p38, and NF-kappaB was investigated.

RESULTS

Exposure of human epithelial cells to L. fermentum does not induce NF-kappaB activation and subsequent IL-8 secretion in HeLa cells, whereas Y. enterocolitica induces NF-kappaB activation and high levels of IL-8. Viable L. fermentum, supernatant of L. fermentum cultures, but not heat-killed L. fermentum, inhibited IL-8 secretion of HeLa cells triggered by Y. enterocolitica. Lactobacillus fermentum-exposed HeLa cells showed decreased Rac, p38, and NF-kappaB activation after Y. enterocolitica infection. Treatment of L. fermentum supernatants with phospholipase C abolished the inhibitory effect, indicating that a secreted phospholipid mediates the antiinflammatory properties of L. fermentum. Adhesion to or invasion of Y. enterocolitica into epithelial cells was not altered by coincubation with L. fermentum.

CONCLUSION

Our results lead to the conclusion that L. fermentum inhibits the Y. enterocolitica-induced IL-8 production by a possibly secreted phospholipid of <10 kDa molecular weight. These data suggest that L. fermentum may have probiotic properties modulating intestinal inflammatory responses and might offer new therapeutic strategies in the treatment of intestinal inflammatory diseases.

Alteration of the canine small-intestinal lactic acid bacterium microbiota by feeding of potential probiotics

Five potentially probiotic canine fecal lactic acid bacterium (LAB) strains, Lactobacillus fermentum LAB8, Lactobacillus salivarius LAB9, Weissella confusa LAB10, Lactobacillus rhamnosus LAB11, and Lactobacillus mucosae LAB12, were fed to five permanently fistulated beagles for 7 days. The survival of the strains and their potential effects on the indigenous intestinal LAB microbiota were monitored for 17 days. Denaturing gradient gel electrophoresis (DGGE) demonstrated that the five fed LAB strains survived in the upper gastrointestinal tract and modified the dominant preexisting indigenous jejunal LAB microbiota of the dogs. When the LAB supplementation was ceased, DGGE analysis of jejunal chyme showed that all the fed LAB strains were undetectable after 7 days. However, the diversity of the intestinal indigenous microbiota of the dogs, as characterized from jejunal chyme plated on Lactobacillus selective medium without acetic acid, was reduced and did not return to the original level during the study period. In all but one dog, an indigenous Lactobacillus acidophilus strain emerged as the dominant LAB strain. In conclusion, strains LAB8 to LAB12 have potential as probiotic strains for dogs as they survive in and dominate the jejunal LAB microbiota during feeding and have the ability to modify the intestinal microbiota.

Antimicrobial potential of four Lactobacillus strains isolated from breast milk

AIMS

The antimicrobial potential of four lactobacilli (Lactobacillus salivarius CECT5713, Lactobacillus gasseri CECT5714, L. gasseri CECT5715 and Lactobacillus fermentum CECT5716), isolated from fresh human breast milk, was evaluated in this study and compared with Lactobacillus coryniformis CECT5711, a reuterin-producing strain isolated from an artisan goat's cheese.

METHODS AND RESULTS

Agar diffusion tests, competitive adhesion assays and mucin expression assays were carried out in order to value the antibacterial properties of the lactobacilli strains. The antibacterial capability of the strains was tested in vivo by using a murine infection model with Salmonella choleraesuis. The results revealed that all the strains studied, displayed antibacterial properties against pathogenic bacteria. However, the antibacterial potential varied among the lactobacilli tested and, in fact, L. salivarius CECT5713 showed not only the best in vitro antibacterial activity, but also the highest protective effect against a Salmonella strain in the murine infection model.

CONCLUSION

The four breast-milk lactobacilli, and particularly L. salivarius CECT5713, possess potent antibacterial activities that result in a higher protection against S. choleraesuis CECT4155 in a mouse infection model.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results suggest that lactobacilli from breast milk could contribute to an anti-infective protection in neonates and would be excellent candidates for the development of infant probiotic products.

Characteristics of the adhesion of PCC®Lactobacillus fermentumVRI 003 to Peyer's patches

The characteristics of the adhesion of PCC Lactobacillus fermentum VRI 003 to Peyer's patches was studied in vitro. The adhesion of L. fermentum 003 was strongly inhibited in the presence of d-mannose and methyl-alpha-d-mannoside although other carbohydrates tested, such as N-acetyl-glucosamine, d-galactose, d-glucose and l-fucose, did not affect the adhesion. Lactobacillus fermentum 003 was shown to strongly attach to mannose immobilized on a surface using BSA, suggesting that L. fermentum 003 specifically adhered to mannose-containing molecule(s). Pretreatment of L. fermentum 003 with proteinase K and trypsin decreased the adhesive capacity and bacterial surface extracts diminished adhesion of L. fermentum 003 indicating that cell surface proteins are involved in adhesion to Peyer's patches. It was concluded that a mannose-specific protein mediated adhesion of L. fermentum 003 to the Peyer's patches.

Application of potential probiotic Lactobacillus fermentum AD1 strain in healthy dogs

Probiotic utilization is becoming increasingly popular in veterinary medicine. However, only few probiotic products are available commercially for use in dogs in our market. Therefore, the aim of our study was to determine the properties of new potential probiotic Lactobacillus fermentum AD1 strain-own canine isolate and to investigate its effect on several microbiological and biochemical parameters in healthy dogs. The strain expressed in vitro survival by pH 3.0 after 3h (86.8%) and in the presence of 1% bile (75.4%). The AD1 strain adhered to the canine and human intestinal mucus. It was sensitive to commonly used antimicrobials. Fifteen healthy dogs were supplemented with 10(9)L. fermentum AD1 for 7 days. At the end of AD1 strain application, numbers of faecal lactobacilli and enterococci increased significantly in the canine faeces. Significant increase of total protein and total lipid and significant reduction of glucose in serum of dogs were noted. These data indicate that L. fermentum AD1 survive transit through the canine gastrointestinal tract, and populate the colon and probably increased absorption of some nutrients. Whether longer time of its application lead to the same results as well as its potential to improve immune function in dogs remains to be determined.

Oral lactobacilli in chronic periodontitis and periodontal health: species composition and antimicrobial activity

BACKGROUND/AIMS

Lactobacilli are known to play an important role in the maintenance of health by stimulating natural immunity and contributing to the balance of microflora. However, their role in chronic periodontitis is unclear. We aimed to identify oral lactobacilli in chronic periodontitis and periodontally healthy subjects, and to determine their antimicrobial activity against putative oral pathogens.

METHODS

A total of 238 Lactobacillus isolates from the saliva and subgingival sites of 20 chronic periodontitis and 15 healthy subjects were collected. In all, 115 strains were identified using rapid amplified ribosomal DNA restriction analysis. Antimicrobial activity against Streptococcus mutans, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia was assessed.

RESULTS

Lactobacilli belonging to 10 species were identified. The most prevalent strains in healthy persons were Lactobacillus gasseri and Lactobacillus fermentum and in chronic periodontitis patients, Lactobacillus plantarum. Obligately homofermentatives, particularly L. gasseri, were less prevalent in chronic periodontitis patients compared with healthy subjects (8% vs. 64% for L. gasseri, P < 0.01). Sixty-nine percent of tested lactobacilli inhibited S. mutans, 88% A. actinomycetemcomitans, 82% P. gingivalis and 65% P. intermedia. The strongest antimicrobial activity was associated with Lactobacillus paracasei, L. plantarum, Lactobacillus rhamnosus, and Lactobacillus salivarius. The strains from periodontally healthy patients showed a lower antimicrobial activity against S. mutans than the strains from chronic periodontitis patients.

CONCLUSION

The composition of oral lactoflora in chronic periodontitis and healthy subjects differs, with a higher prevalence of homofermentative lactobacilli, particularly L. gasseri, in the latter group. Both homo- and heterofermentative oral lactobacilli suppress the growth of periodontal pathogens, but the antimicrobial properties are strain, species and origin specific.

Growth of lactic acid bacteria and Rhizopus oligosporus during barley tempeh fermentation

The zygomycete Rhizopus oligosporus is traditionally used to ferment soybean tempeh, but it is also possible to ferment other legumes and cereals to tempeh. The traditional soybean tempeh harbours a multitude of microorganisms with potentially beneficial or detrimental effects on quality. Lactic acid bacteria (LAB) have positive effects on the safety of soybean tempeh, but the effects of LAB on R. oligosporus growth have not been investigated. We have developed a cereal grain tempeh by fermenting pearled barley with R. oligosporus ATCC 64063. Four LAB species, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus reuteri and Lactococcus lactis were assessed for their growth abilities and their effects on R. oligosporus growth during barley tempeh fermentation. Growth of LAB was assayed as colony forming units (cfu), while growth of R. oligosporus was measured as ergosterol content and hyphal length. The two fungal measurements highly correlated (r=0.83, P<0.001, n=90). The ergosterol content of fungal mycelia ranged from 11.7 to 30.1 mg/g fungal dry matter. L. plantarum multiplied from 4.8 to 7.4 log cfu/g dry tempeh and L. fermentum increased from 4.4 to 6.8 log cfu/g during 24 h incubation at 35 degrees C. L. reuteri and L. lactis had significantly slower growth, with increases from 4.8 to 5.6 log cfu/g and 5.0 to 5.4 log cfu/g, respectively. The growth of R. oligosporus and the final pH (4.9) in barley tempeh were not significantly influenced by any of the LAB investigated.