Rhamnosus Strain GG Research Articles

How xylitol, gluten, and lactose change human gut microbiota Escherichia coli and Lactobacillus rhamnosus GG biofilm

The human gut microbiota is composed of many viruses, bacteria, and fungi. Escherichia coli representatives are facultative anaerobic bacteria in the colon that play a crucial role in the metabolism of lactose, vitamin synthesis, and immune system modulation. E. coli forms a biofilm on the epithelial cell surface of the intestine that can be modified by diet compounds, i.e., gluten, xylitol, lactose, and probiotics. In the present study, the impact of probiotic-derived Lactobacillus rhamnosus GG strain on non-pathogenic E. coli biofilm was examined. The mono- and multispecies biofilm was also treated with gluten, xylitol, and lactose. We used 96-well plates to obtain biofilm growth. Biofilm was stained using crystal violet. To evaluate the type of interaction in mono- and multispecies biofilm, a new formula was introduced: biofilm interaction ratio index (BIRI). To describe the impact of nutrients on biofilm formation, the biofilm formation impact ratio (BFIR) was calculated. The biofilms formed by both examined species are stronger than in monocultures. All the BIRI values were above 3.0. It was found that the monospecies biofilm of L. rhamnosus is strongly inhibited by gluten (84.5%) and the monospecies biofilm of E. coli by xylitol (85.5%). The mixed biofilm is inhibited by lactose (78.8%) and gluten (90.6%). The relations between bacteria in the mixed biofilm led to changes in biofilm formation by E. coli and L. rhamnosus GG. Probiotics might be helpful in rebuilding the gut microbiota after broad spectrum antibiotic therapy, but only if gluten and lactose are excluded from diet.

Pathogenic Biofilm Removal Potential of Wild-Type Lacticaseibacillus rhamnosus Strains.

The emergence of antimicrobial resistance remains one of the greatest public health concerns. Biofilm formation has been postulated as a mechanism of microbial pathogens to resist antimicrobial agents. Lactic Acid Bacteria (LAB) and their metabolites have been proposed to combat bacterial biofilms due to their antimicrobial activity. In this vein, the aim of the present study was to investigate the biofilm removal potential of cell-free supernatants (CFSs) of five wild-type Lacticaseibacillus rhamnosus strains, isolated from Greek natural products, in comparison to the commercially available L. rhamnosus GG strain, against biofilms formed by common foodborne pathogens (Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus). The biofilm removal activity of LAB was assessed on a two-day-old mature biofilm using a microtiter plate-based procedure. Both non-neutralized and neutralized CFSs removed biofilms in a concentration-dependent manner. The biofilm removal activity of the non-neutralized CFSs was significantly higher compared to the neutralized CFSs, as expected, with ranges of 60-89% and 30-80%, respectively. The biofilm removal efficiency of L. rhamnosus OLXAL-3 was significantly higher among the wild-type L. rhamnosus strains tested (20-100% v/v). In conclusion, our results suggest the great potential of the application of wild-type L. rhamnosus strain' CFSs as effective natural agents against pathogenic bacterial biofilms.

Cost-effectiveness of therapeutic infant formulas for cow's milk protein allergy management.

Cow's milk protein allergy (CMPA) is children's most common food allergy. Therapeutic infant formulas for CMPA lead to symptom-free and potentially benefit early tolerance induction and reducing the allergic march in non-breastfed babies. This study assessed the cost-effectiveness of CMPA management with different therapeutic infant formulas in Thailand, which may reflect situations in developing countries throughout Asia. An analytic decision model was developed to simulate the occurrence of eczema, urticaria, asthma, rhinoconjunctivitis, or being symptom-free in infants with CMPA over 36 months. Extensively hydrolyzed casein formula with added probiotic Lacticaseibacillus rhamnosus (previously Lactobacillus rhamnosus) strain GG (EHCF+LGG), extensively hydrolyzed whey formula (EHWF), soy protein-based formula (SPF), and amino acid formula (AAF) were compared from the healthcare payer perspective. The results from a prospective cohort study were used for comparative effectiveness measures, while local experts were interviewed to estimate the healthcare resource used in the management of CMPA. The costs of healthcare resources were obtained from standard, publicly available sources. The direct medical cost of CMPA management was lowest for EHCF+LGG (USD 1,720), followed by SPF (USD 2,090), EHWF (USD 2,791), and AAF (USD 7,881). Compared with other formulas, EHCF+LGG was expected to save USD 370 (SPF), USD 1,071 (EHWF), and USD 6,161 (AAF) in the total cost of CMPA management over 36 months. In conclusion, EHCF+LGG was the most cost-effective strategy for managing non-breastfed infants with CMPA. This strategy was associated with more children developing immune tolerance to cow's milk and being symptom-free, contributing to overall cost-saving potential.

Lacticaseibacillus rhamnosus Strain GG (LGG) Regulate Gut Microbial Metabolites, an In Vitro Study Using Three Mature Human Gut Microbial Cultures in a Simulator of Human Intestinal Microbial Ecosystem (SHIME).

In the present research, we investigated changes in the gut metabolome that occurred in response to the administration of the Laticaseibacillus rhamnosus strain GG (LGG). The probiotics were added to the ascending colon region of mature microbial communities established in a human intestinal microbial ecosystem simulator. Shotgun metagenomic sequencing and metabolome analysis suggested that the changes in microbial community composition corresponded with changes to metabolic output, and we can infer linkages between some metabolites and microorganisms. The in vitro method permits a spatially-resolved view of metabolic transformations under human physiological conditions. By this method, we found that tryptophan and tyrosine were mainly produced in the ascending colon region, while their derivatives were detected in the transverse and descending regions, revealing sequential amino acid metabolic pathways along with the colonic tract. The addition of LGG appeared to promote the production of indole propionic acid, which is positively associated with human health. Furthermore, the microbial community responsible for the production of indole propionic acid may be broader than is currently known.

Comparison between Lactobacillus rhamnosus GG and LuxS-deficient strain in regulating gut barrier function and inflammation in early-weaned piglets.

Early weaning-induced stress impairs the intestinal barrier function and adversely affects the health of piglet. Probiotics can be used to prevent and treat various intestinal diseases. Lactobacillus rhamnosus GG (LGG) has an LuxS/AI-2 quorum sensing (QS) system that senses environmental changes through chemical signaling molecules. The aim of the study was to explore whether luxS mutant affects the protective role of LGG in the gut barrier of weaned piglets by comparing the luxS mutant (ΔluxS) with its wild-type (WT). Newborn piglets were orally administered with WT and ΔluxS at dosage of 109 CFU, respectively. Accordingly, newborn piglets in the Con group were orally administered with PBS. Piglets were weaned on day 21 and euthanized on day 24, three days following weaning. Supplementation of ΔluxS in advance significantly boosted the relative abundances of healthy microbes (including Catenibacterium, Eubacterium, Lachnospiraceae and Bifidobacterium). WT and ΔluxS maintain intestinal barrier function mainly by promoting intestinal villus to crypt ratio (VCR), occludin protein expression and mucus secretion (P<0.05). Furthermore, LGG reduces pro-inflammatory mediators by inhibiting TLR4 and MAPK signal transduction (P<0.05). Both WT and ΔluxS were shown to resist weaning stress by enhancing the intestinal barrier function of piglets. It has to be said that the ability of ΔluxS to maintain intestinal tissue morphology and promote mucus secretion significantly decreased compared with that of WT.

Production of kurut (kurt) using probiotic Lacticaseibacillus rhamnosus GG strain in combination with a yeast isolated from Kazakhstan kurut

Kuruts are traditional acid-coagulated fermented dairy products in semisolid or dried form. The present study used probiotic Lacticaseibacillus rhamnosus GG (LGG) and Cryptococcus laurentii yeast, a kurut isolate, to make mixed-fermentation kurut. In addition, kurut was fermented with L. rhamnosus GG as starter. Kurut was also fermented with kefir grains representing a traditional way to initiate the fermentation. The viability of probiotic L. rhamnosus GG strain and physicochemical properties of semisolid kurut products were monitored during storage over 22 days at 4°C. The tested probiotic strain showed viability higher than 7 log CFU/mL in both mixed-fermentation and single-strain-fermentation kurut during storage at 4°C. When prepared with probiotic bacteria, the syneresis values of mixed-fermentation kurut were lower (p &amp;gt; 0.05) than single-strain-fermentation kurut. The flavor and overall acceptability scores for kurut prepared using the combination of probiotic LGG and C. laurentii yeast as starter culture were higher than for the other samples at 11 days of storage (p &amp;gt; 0.05). Taking the above into consideration, probiotic kuruts obtained by milk fermentation inoculated with co-culture of L. rhamnosus GG and C. laurentii yeast could be potential probiotic products to be produced in the dairy industry.

Persistence of the Probiotic Lacticaseibacillus rhamnosus Strain GG (LGG) in an In Vitro Model of the Gut Microbiome.

The consumption of probiotics is widely encouraged due to reports of their positive effects on human health. In particular, Lacticaseibacillus rhamnosus strain GG (LGG) is an approved probiotic that has been reported to improve health outcomes, especially for gastrointestinal disorders. However, how LGG cooperates with the gut microbiome has not been fully explored. To understand the interaction between LGG and its ability to survive and grow within the gut microbiome, this study introduced LGG into established microbial communities using an in vitro model of the colon. LGG was inoculated into the simulated ascending colon and its persistence in, and transit through the subsequent transverse and descending colon regions was monitored over two weeks. The impact of LGG on the existing bacterial communities was investigated using 16S rRNA sequencing and short-chain fatty acid analysis. LGG was able to engraft and proliferate in the ascending region for at least 10 days but was diminished in the transverse and descending colon regions with little effect on short-chain fatty acid abundance. These data suggest that the health benefits of the probiotic LGG rely on its ability to transiently engraft and modulate the host microbial community.

Exercise Training and Probiotic Lacticaseibacillus rhamnosus GG Reduce Tetracycline-Induced Liver Oxidative Stress and Inflammation in Rats with Hepatic Steatosis.

Lifestyle modification with regular exercise can improve metabolic diseases by reducing lipid profile and inflammation. Probiotics have been recently recommended not only for gastrointestinal diseases but also for metabolic and even degenerative diseases. Therefore, in the present study, the effect of high-intensity interval training (HIIT) and Lacticaseibacillus rhamnosus strain GG (LGG) as a probiotic on tetracycline-induced hepatic steatosis in an animal model was evaluated. Eighty male Wistar rats were randomly divided into eight groups (n = 10 in each group): control, LGG, HIIT, LGG + HIIT, tetracycline-induced (TTC), TTC + LGG, TTC + HIIT, and TTC + LGG + HIIT. The rats are treated by intraperitoneal injection (IP) with 140mgkg-1 tetracycline, an antibiotic previously known to induce steatosis. The exercise training groups performed HIIT 5days/week for 5weeks, and 107CFU/ml of Lacticaseibacillus rhamnosus GG was gavaged for the LGG groups 5days/week for 5weeks. Fatty droplets in the hepatocyte were considered with Oil Red staining. TTC-receiving rats have more lipid accumulation and larger lipid droplets in the liver compared to healthy animals. The two-way ANOVA showed that the interaction of LGG and HIIT significantly decreased LDL, cholesterol, and triglyceride in the healthy rats (p < 0.05). In TTC-receiving rats, the interaction of LGG and HIIT significantly increased HDL and SOD and significantly decreased triglyceride, ALP, AST, and ALT (p < 0.05). The consumption of probiotic LGG, along with HIIT with control of lipid profile and liver enzymes and improvement of the oxidative capacity, neutralizes the damage of TTC to liver tissue. Therefore, this protocol can be recommended for people with hepatic steatosis.

Gut Bifidobacteria enrichment following oral Lactobacillus-supplementation is associated with clinical improvements in children with cystic fibrosis

BackgroundRelationships between gut microbiomes and airway immunity have been established in murine and human studies of allergy and asthma. Early life Lactobacillus supplementation alters the composition and metabolic productivity of the gut microbiome. However, little is known of how Lactobacillus supplementation impacts the gut microbiota in children with cystic fibrosis (CF) and whether specific microbiota states that arise following gut microbiome manipulation relate to pulmonary outcomes.MethodsStool samples were collected from CF patients enrolled in a multi-center, double-blind, randomized placebo-controlled trial of daily Lactobacillus rhamnosus strain GG (LGG) probiotic supplementation over a 12-month period. Fecal 16S rRNA biomarker sequencing was used to profile fecal bacterial microbiota and analyses were performed in QiiME.ResultsBifidobacteria-dominated fecal microbiota were more likely to arise in LGG-treated children with CF (P = 0.04). Children with Bifidobacteria-dominated gut microbiota had a reduced rate of pulmonary exacerbations (IRR = 0.55; 95% CI 0.25 to 0.82; P = 0.01), improved pulmonary function (+ 20.00% of predicted value FEV1; 95% CI 8.05 to 31.92; P = 0.001), lower intestinal inflammation (Calprotectin; Coef = − 16.53 μg g−1 feces; 95% CI − 26.80 to − 6.26; P = 0.002) and required fewer antibiotics (IRR = 0.43; 95% CI 0.22 to 0.69; P = 0.04) compared to children with Bacteroides-dominated microbiota who were less likely to have received LGG.ConclusionsThe majority of pediatric CF patients in this study possessed a Bacteroides- or Bifidobacteria-dominated gut microbiota. Bifidobacteria-dominated gut microbiota were more likely to be associated with LGG-supplementation and with better clinical outcomes.

Human Breast Milk: A Source of Potential Probiotic Candidates.

This study focuses on the isolation of lactobacilli/bifidobacteria from human breast milk and their first characterization, in the perspective to find new probiotic candidates to be included in food products. More specifically, breast-milk-isolated strains demonstrated a very good aptitude to adhere to intestinal cells, in comparison with L. rhamnosus GG strain, taken as reference. The same behavior has been found for hydrophobicity/auto-aggregation properties. A remarkable antagonistic activity was detected for these isolates not only against spoilage and pathogenic species of food interest, but also against the principal etiological agents of intestinal infections. Indeed, isolated strains impaired spoilage and pathogenic species growth, as well as biofilm formation by gut pathogens. In addition, breast milk strains were characterized for their antibiotic susceptibility, displaying species-specific and strain-specific susceptibility patterns. Finally, to assess their technological potential, the fermentation kinetics and viability of breast milk strains in pasteurized milk were investigated, also including the study of the volatile molecule profiles. In this regard, all the strains pointed out the release of aroma compounds frequently associated with the sensory quality of several dairy products such as acetic acid, diacetyl, acetoin, acetaldehyde. Data here reported point up the high potential of breast-milk-isolated strains as probiotics.

Colonization of Lactobacillus rhamnosus GG in Cirrhinus molitorella (Mud Carp) Fingerling: Evidence for Improving Disease Resistance and Growth Performance

The use of probiotic bacteria can not only enhance the nutritional utilization of fish feeds to produce more biomass but can also provide a practically “safer” alternative to the fish farming industry to reduce the abuse of antibiotics and drugs. This study investigated the possibility of colonizing Lactobacillus rhamnosus strain GG (LGG) to the intestine of Cirrhinus molitorella (mud carp) fingerling. Colonization of LGG was observed in gut tissue after 14 days of administration with a diet supplemented with 1 × 108 CFU/mL LGG. Moreover, growth performance parameters of the LGG-supplemented diet group, including relative weight gain, feed conversion ratio and feed efficiency, were found about two-fold higher than the control group after 60 days. In addition, fish fed with an LGG-supplemented diet for 60 days showed substantial resistance against the infection of pathogenic bacterial Aeromonas hydrophila, with a relative survival rate of up to 57% compared to the control group. In summary, the results indicated that LGG as dietary supplement for mud carp fingerling can enhance nutrition utilization and better protect fish against the infection of Aeromonas hydrophila. The results provide an insight to the fish farming industry, encouraging a reduction in the use of antibiotics and drugs and the production of “safer” mud carp for the market at a manageable cost.

Lacticaseibacillus rhamnosus GG Survival and Quality Parameters in Kefir Produced from Kefir Grains and Natural Kefir Starter Culture.

The study aimed to determine the effect of starter cultures (kefir grains and natural kefir starter culture without grains) on Lacticaseibacillus rhamnosus GG (LGG) survival and on the quality characteristics of kefir. To this end, the viability of probiotic L. rhamnosus GG strain and the rheological properties and quality parameters of kefir beverages were tested during storage over 21 days at 4 °C. The final LGG counts were 7.71 and 7.55 log cfu/mL in natural kefir starter culture and kefir grain, respectively. When prepared with probiotic bacteria, the syneresis values of kefir prepared using natural kefir starter culture was significantly lower (p < 0.05) than that of kefir made using grains. However, the viscosity indices, hysteresis loop, and dynamic moduli were similar between kefir made with natural kefir starter culture and other kefir formulations (p > 0.05). Moreover, all samples showed shear-thinning behavior. The flavor scores for kefir prepared using natural kefir starter culture were significantly higher than for the other samples (p < 0.05), but overall acceptability was similar at the 10-day assessment across both starters (with and without grain) after the addition of probiotic bacteria (p > 0.05). Overall, the results indicate that natural kefir starter culture could be a potential probiotic carrier.

Probiotic Lacticaseibacillus rhamnosus GG Increased Longevity and Resistance Against Foodborne Pathogens in Caenorhabditis elegans by Regulating MicroRNA miR-34.

In this study, we investigated the relation of probiotic activity of Lacticaseibacillus rhamnosus strain GG (LGG) and expression of microRNA to immune response and longevity in Caenorhabditis elegans host model. First, we evaluated the survival rate of C. elegans due to LGG exposure and bacterial colonization in the intestine. Next, the expression of mRNA and miRNA was analyzed in C. elegans exposure to LGG for 24 h using microarray. After exposure to LGG to C. elegans, colonized LGG was observed in the intestines of C. elegans and induced to extend lifespan. Moreover, persistent LGG in the intestine significantly enhanced the resistance of C. elegans exposed to both pathogenic bacteria and prolonged the lifespan of C. elegans. Transcriptome analysis indicated that LGG affected the expression levels of genes related to the innate immune response and upregulated the abundance of genes in multiple pathways of C. elegans, including Wnt signaling, TGF-beta signaling and mitogen-activated protein kinase (MAPK) pathways. In addition, qRT-PCR analysis confirmed that the expression of antibacterial genes was increased by LGG. Moreover, as the expression of microRNA miR-34 and immune-related pathways increased by exposure to LGG, the lifespan of C. elegans increased. However, in the miR-34 mutant C. elegans, the lifespan by LGG did not increase, so it was determined that miR-34 indirectly affects immune-related pathways. There was no significant difference in the expression of PMK-1 for LGG exposure in miR-34 mutants, suggesting that miR-34 may regulate PMK-1. In conclusion, we suggest that exposure of LGG to C. elegans enhances lifespan and resistance to food-borne pathogen infection by stimulating miR-34 and indirectly promoting PMK-1 activity.

Lacticaseibacillus rhamnosus Reduces the Pathogenicity of Escherichia coli in Chickens.

Lacticaseibacillus rhamnosus is a recognized probiotic that is widely used in scientific research and clinical applications. This study found that the Lacticaseibacillus rhamnosus GG (LGG) strain can reduce the adhesion of Escherichia coli (E. coli) to primary chicken intestinal epithelial cells by 75.7% and inhibit 41.7% of the E. coli that adhere to intestinal epithelial cells. Additionally, LGG showed strong inhibitory ability on the growth of E. coli, Staphylococcus aureus, Salmonella Paratyphi B, and Salmonella Enteritidis in vitro. Furthermore, the influence of LGG on the growth performance, intestinal flora, immunity, and disease resistance of chickens was explored. Chickens fed with LGG exhibited increased average daily weight gain and concentrations of sIgA, IgG, and IgM than did controls. After 21 days of feeding, a diet with LGG increased the diversity of intestinal microbiota and maintained intestinal health. Moreover, LGG promoted immunologic barriers by upregulating cytokines and chemokines via the Toll-like receptor. The major pro-inflammatory factors, including Myd88, NF-κB, Il6, and Il8, were upregulated compared to controls. After being challenged with E. coli, the survival rate of chickens fed with LGG was significantly higher than those in the control group, and decreased numbers of E. coli were detected in the heart and lungs of the LGG group. In summary, oral administration of LGG to chickens could improve growth performance, maintain intestinal homeostasis, and enhance innate immune response and disease resistance.

Coating Lacticaseibacillus rhamnosus GG in Alginate Systems: an Emerging Strategy Towards Improved Viability in Orange Juice

Fruit juices are successfully proposed as suitable probiotic vehicles, but researchers’ efforts should be developed to avoid effects of bacteria overgrowing on sensory and nutritional cues of final products and to preserve viability of probiotic bacteria during storage. In the present study, encapsulation of Lacticaseibacillus rhamnosus GG strain in alginate systems was performed through ionotropic gelation technology. The alginate systems were optimized by using Box-Behnken Design to investigate the influence of three independent variables at three different levels: particle mean size and polydispersity index. The optimized probiotic-loaded alginate particles were added to orange juice samples. The viability of the probiotic strain, both as free and microencapsulated, was evaluated in orange juice stored at 5°C for 35 days. Morphology and size of probiotic-loaded alginate particles were found suitable for incorporation into juice. TEM analysis revealed that unloaded systems were clustered as nanoparticles (CL_NP), while the loaded sample appeared as a coated system (Coated_LGG). Microbiological evaluation revealed that the encapsulation assured the survival of Coated_LGG, with a reduction of less than 1-unit log in cellular density after 35 days of refrigerated storage in orange juice. Results indicated that the encapsulated bacteria did not affect the macroscopic properties neither the microbiological characteristic of orange juice; thus, it can be proposed as functional food.

Microencapsulation of Lactobacillus casei and Lactobacillus rhamnosus in pectin and pectin-inulin microgel particles: Effect on bacterial survival under storage conditions

The main objective of the research was to evaluate the performance of synbiotic delivery systems using pectin microgels on the protection of two probiotic strains (Lactobacillus casei ATCC 393 and Lactobacillus rhamnosus strain GG [ATCC 53103]) to simulated gastrointestinal digestion (GD) and storage conditions (4 ± 1 °C) in a 42 days trial. Microgel particles were prepared by ionotropic gelation method and three variables were evaluated: incubation time (24 and 48 h), free vs encapsulated cells, and presence or absence of prebiotic (commercial and Jerusalem artichoke inulin). Results demonstrated an encapsulation efficiency of 96 ± 4% into particles with a mean diameter between 56 and 118 μm. The viability of encapsulated cells after 42 days storage stayed above 7 log units, being encapsulated cells in pectin-inulin microgels more resistant to GD compared to non-encapsulated cells or without prebiotics. In all cases incubation time influenced the strains' survival.

Growth of Lactic Acid Bacteria on Gold-Influence of Surface Roughness and Chemical Composition.

The main focus of this work was to establish a correlation between surface topography and chemistry and surface colonization by lactic acid bacteria. For this reason, we chose gold substrates with different surface architectures (i.e., smooth and nanorough) that were characterized by atomic force microscopy (AFM), electron scanning microscopy (SEM), and X-ray diffractometry (XRD). Moreover, to enhance biocompatibility, we modified gold substrates with polymeric monolayers, namely cationic dextran derivatives with different molar masses. The presence of those layers was confirmed by AFM, infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). In order to determine the adhesion abilities of non-modified and modified gold surfaces, we tested three lactic acid bacteria (LAB) strains (i.e., Lactobacillus rhamnosus GG, Lactobacillus acidophilus, and Lactobacillus plantarum 299v). We have shown that surface roughness influences the surface colonization of bacteria, and the most significant impact on the growth was observed for the Lactobacillus rhamnosus GG strain. What is more, covering the gold surface with a molecular polymeric film by using the layer-by-layer (LbL) method allows additional changes in the bacterial growth, independently on the used strain. The well-being of the bacteria cells on tested surfaces was confirmed by using selective staining and fluorescence microscopy. Finally, we have determined the bacterial metabolic activity by measuring the amount of produced lactic acid regarding the growth conditions. The obtained results proved that the adhesion of bacteria to the metallic surface depends on the chemistry and topography of the surface, as well as the specific bacteria strain.

The Ability of Riboflavin-Overproducing Lactiplantibacillus plantarum Strains to Survive Under Gastrointestinal Conditions.

Riboflavin, vitamin B2, is essential for humans and has to be obtained from the diet. Some lactic acid bacteria (LAB) produce this vitamin, and they can be used for in-situ fortification of foods. This could be an alternative to supplementation with chemically synthesized vitamin, to palliate riboflavin deficiencies in specific groups of people. Moreover, if the producing LAB could survive in the gastrointestinal stress (GIT) they could be added as probiotics in this environment. In the present study we tested two riboflavin-overproducing Lactiplantibacillus plantarum strains (M5MA1-B2 and M9MG6-B2), spontaneous mutants of LAB isolated from chicha, a traditional Andean beverage. These two LAB, and also their isogenic strains M5MA1-B2[pRCR12] and M9MG6-B2[pRCR12], expressing the mCherry protein from the pRCR12 plasmid, were evaluated in vitro under simulated GIT conditions. Among other, specifically developed protein fluorescence assays were used. The four LAB showed similar levels of adhesion (>6.0%) to Caco-2 cells, higher than that of the probiotic Lacticaseibacillus rhamnosus GG strain (4.51%). Thus, LAB biofilm formation was assessed in the labeled cells by intracellular mCherry fluorescence and in the unlabeled parental strains by crystal violet staining. Both methods detected the formation of consistent biofilms by the L. plantarum strains. The quantification of mCherry fluorescence was also used to analyze LAB auto-aggregation properties. High levels of auto-aggregation were detected for both M5MA1-B2[pRCR12] and M9MG6-B2[pRCR12]. Survival of LAB included in a commercial cereal-based food matrix (Incaparina) under GIT conditions was also evaluated. The four LAB were resistant in vitro to the stomach and intestinal stresses, and proliferated in this environment, indicating a protective and nutritional effect of the Incaparina on the bacteria. Also, M9MG6-B2 survival in the presence or absence of Incaparina was evaluated in vivo in a BALB/c mouse model. The administration of the M9MG6-B2 strain alone or together with Incaparina had no adverse effect on the health, growth and/or well-being of the rodents. In addition, an increment in the villus length/crypt depth ratio was observed. The overall results obtained indicate that the LAB studied have probiotic characteristics of interest for the development of functional foods.

Development of enteric polymer-based microspheres by spray-drying for colonic delivery of Lactobacillus rhamnosus GG.

Antibiotics are well-known disruptive elements of the intestinal microbiota and antibiotic-associated diarrhea appeared as the most common complication related with post-antibiotic dysbiosis. Lactobacillus rhamnosus GG (LGG) strain is very effective in preventing antibiotic-associated diarrhea in children and adults. However, as any probiotics, it is concerned by the loss of viability during storage and gastrointestinal transit. The aim of this study was to develop an encapsulation system suitable for the specific colonic delivery of LGG strain after oral administration. For this purpose, spray-dried Eudragit® S100 microparticles encapsulating LGG bacteria were developed by using an aqueous based spray-drying approach, avoiding the use of organic solvents. Carbohydrates were added to the formulation since they are widely used as protective agents of bacteria against the harmful effect of dehydration stress. Here, both Surface Enhanced Raman Scattering (SERS) and conventional plate count methods showed that carbohydrates increased the survival ratio of bacteria after spray-drying from 3 to more than 50%. Moreover, these protective agents ensured low residual moisture content thus providing great stability of the cells in the spray-dried powder during storage. Significant improvement of the cell viability in simulated gastro intestinal fluid (SGIF) was observed for encapsulated cells as compared with free LGG bacteria for which no viable cell was detectable after 1h incubation in gastric fluid only. As a consequence, 4.5×107 CFU/g of encapsulated LGG were found viable after incubation of microparticles 1h in Simulated Gastric Fluid followed by 6h in Simulated Intestinal Fluid, corresponding to less than 3 log reduction of viable cells during the 7h incubation in Simulated Gastro Intestinal Fluid. These results attested that the developed encapsulation system is suitable for its use as a bacteria carrier for specific colonic delivery.

Effect of the Lactobacillus rhamnosus strain GG and tagatose as a synbiotic combination in a dextran sulfate sodium-induced colitis murine model

Synbiotics, a combination of prebiotics and probiotics, produce synergistic effects to promote gastrointestinal health. Herein, we investigated the synbiotic interaction between the Lactobacillus rhamnosus strain GG (LGG; a probiotic strain) and tagatose (a prebiotic) in a dextran sulfate sodium (DSS)-induced colitis murine model. Initially, body weight, food intake, and clinical features were dramatically decreased after treatment with DSS, and the addition of LGG, tagatose, or both ameliorated these effects. In our pyrosequencing analysis of fecal microbiota, DSS treatment increased the abundance of Proteobacteria and decreased that of Firmicutes. When LGG and tagatose were administered as synbiotics, the gut microbiota composition recovered from the dysbiosis caused by DSS treatment. In particular, the abundance of Bacteroides, Lactobacillus, and Akkermansia was significantly associated with probiotic, prebiotic, and synbiotic treatments. Taken together, our results suggest that LGG and tagatose as synbiotics can alleviate colitis, and synbiotics could be applied as dietary supplements in dairy foods such as yogurt and cheese.