Antagonistic activity of probiotic lactobacilli and bifidobacteria against entero- and uropathogens

AIM: To develop in vitro assays for comparing the antagonistic properties and anti-oxidative activity of probiotic Lactobacillus and Bifidobacterium strains against various entero- and urinary pathogens. METHODS AND RESULTS: The antagonistic activity of five probiotic lactobacilli (Lactobacillus rhamnosus GG, Lactobacillus fermentum ME-3, Lactobacillus acidophilus La5, Lactobacillus plantarum 299v and Lactobacillus paracasei 8700:2) and two bifidobacteria (Bifidobacterium lactis Bb12, Bifidobacterium longum 46) against six target pathogens was estimated using different assays (solid and liquid media, anaerobic and microaerobic cultivation) and ranked (low, intermediate and high). Bacterial fermentation products were determined by gas chromatography, and the total anti-oxidative activity of probiotics was measured using linolenic acid test. Pyelonephritic Escherichia coli was highly suppressed by GG and both bifidobacteria strains. Lactobacilli strains 8700:2, 299v and ME-3 were the most effective against Salmonella enterica ssp. enterica in microaerobic while ME-3 and both bifidobacteria expressed high activity against Shigella sonnei in anaerobic milieu. Lact. paracasei, Lact. rhamnosus and Lact. plantarum strains showed intermediate antagonistic activity against Helicobacter pylori under microaerobic conditions on solid media. The highest anti-oxidative activity was characteristic for Lact. fermentum ME-3 (P < 0.05). No efficient antagonist against Clostridium difficile was found. The positive correlations between the pH, lactic acid production and anti-microbial activity for all tested probiotics were assessed. CONCLUSIONS: Developed experimental assays enable to compare the anti-microbial and -oxidative activity of Lactobacillus and/or Bifidobacterium probiotics, which have been claimed to possess the ability of suppressing the growth of various enteric and urinary pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Screening Lactobacillus and Bifidobacterium sp. strains according to their activity in various environmental conditions could precede the clinical efficacy studies for adjunct treatment with probiotics in cure of different gastrointestinal and urinary tract infections.     

Assessment of the probiotic potential of lactic acid bacteria isolated from kefir grains: evaluation of adhesion and antiproliferative properties in in vitro experimental systems

The main objective of this study was to isolate lactic acid bacteria from kefir grains and investigate their probiotic potential. In this study, 48 bacterial strains were isolated from kefir grains, whereas 39 strains were categorized to the genus Lactobacillus. Evaluation of the probiotic potential of the isolated stains was performed, including resistance to low pH, tolerance to pepsin, pancreatin and bile salts, and antibiotic resistance. In addition, evaluation of adhesion and antiproliferative properties in in vitro experimental systems was also conducted. Strains SP2 and SP5 that displayed the best performance in the conducted in vitro tests were selected for further studies. Firstly, genotypic identification of the two strains was performed by partial 16S rRNA gene sequencing, BLAST analysis, and species-specific multiplex PCR assay. The two strains were confirmed to be Pediococcus pentosaceus SP2 and Lactobacillus paracasei SP5. Then, the adhesion properties of the two strains were examined in vitro. Both strains displayed substantial adherence capacity to HT-29 human colon cancer cells. Moreover, a significant decrease of HT-29 cell growth after treatment with viable P. pentosaceus SP2 or L. paracasei SP5 was recorded. In addition, downregulation of anti-apoptotic genes and over-expression of cell cycle–related genes was recorded by real-time PCR analysis. Treatment with conditioned media of the two strains also caused significant reduction of cancer cell proliferation in a time- and concentration-dependent manner. P. pentosaceus SP2 and L. paracasei SP5 displayed the best probiotic properties that exerted substantial adherence on human colon cancer cells as well as significant anti-proliferative properties.     

Assessment of cell surface properties and adhesion potential of selected probiotic strains

Aim:  To evaluate the physicochemical cell surface and adhesive properties of selected probiotic strains for human use.
Methods and Results:  Probiotic strains, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus paracasei , Lactobacillus rhamnosus GG, Lactobacillus brevis , Lactobacillus casei , Leuconostoc mesenteroides and Pediococcus acidilactici were tested for the physicochemical properties of cell surfaces and the adhesion abilities against foodborne pathogens. Bif .  longum B6 (53·6%) and Lact .  rhamnosus GG (46·5%) showed the highest hydrophobicity, while the least affinity to xylene was observed in Ped .  acidilactici (10·4%). Bifidobacterium longum B6 showed the strongest coaggregation phenotype with Listeria monocytogenes (53·0%), Shigella boydii (42·0%) and Staphylococcus aureus (45·9%). Lactobacillus rhamnosus GG had the strong binding ability to Caco-2 cells and effectively inhibited the adhesion of L .  monocytogenes , Salmonella Typhimurium, Sh .  boydii and Staph .  aureus to Caco-2 cells. The hydrophobicity was highly correlated with coaggregative abilities and competitive inhibition, suggesting a good relationship between in vitro adhesion and in vivo colonization.
Conclusion:  The results suggest that Bif .  longum B6 and Lact .  rhamnosus GG can be candidate probiotics available for human consumption.
Significance and Impact of the Study:  Because the use of probiotic strains has been more concerned with their beneficial effects in the GI tract, it is essential to examine the potential of probiotic strains based on the physicochemical properties in terms of bacterial-binding and adhesion capabilities.     

Rapid identification of Lactobacillus and Bifidobacterium in probiotic products using multiplex PCR

Lactic acid bacteria (LAB) are beneficial for the gastrointestinal tract and reinforce immunity in human health. Recently, many functional products using the lactic acid bacteria have been developed. Among these LAB, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum are frequently used for probiotic products. In order to monitor these LAB in commercial probiotic products, a multiplex PCR method was developed. We designed four species-specific primer pairs for multiplex PCR from the 16S rRNA, 16S-23S rRNA intergenic spacer region, and 23S rRNA genes in Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum. Using these primer pairs, 4 different LAB were detected with high specificity in functional foods. We suggest that the multiplex PCR method developed in this study would be an efficient tool for simple, rapid, and reliable identification of LAB used as probiotic strains.     

Probiotic properties of Lactobacillus strains with high cinnamoyl esterase activity isolated from jeot-gal,a high-salt fermented seafood

Cinnamoyl esterases (CEs) improve the bioavailability of caffeic acid, a potent antioxidant with beneficial health effects. This study aimed to characterize the probiotic properties of 14 strains of CE-producing lactic acid bacteria (LAB) isolated from jeot-gal, a high-salt fermented seafood. We evaluated properties of the probiotic LAB with high CE activity, including tolerance to low pH and bile salts, antimicrobial activity, surface hydrophobicity, adhesion, and immunomodulatory effects, in vitro. All LAB tested tolerated pH 2.0 and 3% Oxgall, i.e., conditions comparable with those in the gastrointestinal environment. Three isolates, Lactobacillus paracasei JBCC10650, Lactobacillus pentosus JBCC10659, and Lactobacillus plantarum JBCC10543, showed stronger adherence to epithelial cells (12.3, 9.6, and 9.4%) than a commercial probiotic Lactobacillus rhamnosus GG (9.1%; p < 0.05), and exhibited broad antibacterial activity against putative pathogens. Most of the 14 LAB strains were able to regulate mRNA expression of pro- and anti-inflammatory cytokines in macrophages, indicating their potential immunomodulatory effects. Our findings suggest that the newly isolated CE-producing probiotics may show beneficial health effects by supporting the host immune system.     

Probiotic properties of Lactobacillus strains isolated from the feces of breast-fed infants and Taiwanese pickled cabbage

This study assessed potential probiotic Lactobacillus strains isolated from the feces of breast-fed infants and from Taiwanese pickled cabbage for their possible use in probiotic fermented foods by evaluating their (i) in vitro adhesive ability, resistance to biotic stress, resistance to pathogenic bacteria, and production of β-galactosidase; (ii) milk technological properties; and (iii) in vivo adhesive ability, intestinal survival and microbial changes during and after treatment. Five Lactobacillus isolates identified as Lactobacillus reuteri F03, Lactobacillus paracasei F08, Lactobacillus rhamnosus F14, Lactobacillus plantarum C06, and Lactobacillus acidophilus C11 that showed resistance to gastric juice and bile salts were selected for further evaluation of their probiotic properties. All the strains demonstrated the ability to adhere to Caco-2 cells, particularly, strain L. plantarum C06 and L. reuteri F03 showed satisfactory abilities, which were similar to that of the reference strain L. rhamnosus GG. The strains L. paracasei F08 and L. acidophilus C11 had the highest β-galactosidase activity. Most of the strains were resistant to aminoglycosides and vancomycin but sensitive to ampicillin, erythromycin, and penicillin. All the 5 strains elicited antibacterial activity against both Gram-positive (Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) and -negative (Escherichia coli and Salmonella enterica) pathogens. Moreover, the strains L. reuteri F03, L. paracasei F08, and L. plantarum C06 could grow rapidly in milk without nutrient supplementation and reached 10? cfu/mL after 24 h of fermentation at 37 °C. The viable cell counts of the 3 strains remained above 10? cfu/mL after 21 d of storage at 4 °C. In the animal feeding trial, the number of intestinal lactobacilli increased significantly after administration of milk fermented with the 3 strains, and the counts of fecal coliforms and Clostridium perfringens were markedly reduced. Lactobacillus strains could also survive in the ileal intestinal tissue of the treated rats. Technologically interesting Lactobacillus isolates may be used in the future as probiotic starter cultures for manufacturing novel fermented foods.     

Characterization of lactobacilli towards their use as probiotic adjuncts in poultry

AIMS: A total of 112 strains of lactic acid bacteria of duck origin were studied for their use as a probiotic feed supplement. METHODS AND RESULTS: In vitro studies included aggregation, co-aggregation, cell surface hydrophobicity and adhesion activities on poultry crop cells and human Hep2-cells. Additionally, growth with bile acids (chicken bile, ox gall and taurocholic acid) and tolerance to acidic pH were tested. Among all the isolates, two strains (Lactobacillus animalis TMW 1.972 and Lactobacillus salivarius TMW 1.992) were selected for a survival test in poultry. Monitoring and differentiation of these strains was achieved by selective detection as rifampicin and erythromycin double-resistant mutants. After a single feed administration, both micro-organisms were shown to persist in the crop and caecum of ducks for a period of 18 and 22 days, respectively. For identification of Lact. animalis and Lact. salivarius, two specific PCRs targeted against 16S rDNA were developed. CONCLUSIONS: Within the autochtoneous microflora of ducks, two strains of lactobacilli exhibited strong potential as probiotic adjuncts. The results indicate that the natural gut microflora of poultry serves as an excellent source for optimal strains. SIGNIFICANCE AND IMPACT OF THE STUDY: A general strategy for the selection of probiotic strains is presented. The suggested sequence of tests allows identification of the most promising candidates within complex ecosystems or large strain collections with minimal expenditure.     

Degradation of 16S rRNA and attributes of viability of viable but nonculturable probiotic bacteria

Aims:  To assess the stability of 16S rRNA of viable but nonculturable (VBNC) probiotics during storage when compared with different attributes of viability.
Methods and Results:  Levels of RNA of the probiotic strains Bifidobacterium longum 46, B. longum 2C and B. animalis subsp. lactis Bb-12 were monitored during storage in fermented and nonfermented foods. Cells which gradually lost their culturability in fermented products retained high level of rRNA, whereas rRNA of acid-killed control cells decreased at faster rate. Furthermore, the viability of B. longum 2C was monitored during storage by measuring changes in reductase activity, cytoplasmic membrane integrity and esterase activity using a flow cytometer. All of the culture-independent viability assays suggested that the cells remained viable during storage. In nonfermented media, the observed losses in culturability were smaller, and the changes in cell counts were comparable with the changes in rRNA levels.
Conclusions:  Viable but nonculturable probiotics maintain high levels of rRNA and retain properties of viable bacteria including reductase activity. Quantification of 16S rRNA complements culture-independent viability assays.
Significance and Impact of the Study:  Culture-independent viability assays allow the detection of VBNC probiotics, and can be used parallel to conventional culture-dependent methods to obtain accurate information on probiotic viability.     

Polyphasic approach to bacterial dynamics during the ripening of Spanish farmhouse cheese, using culture-dependent and -independent methods

We studied the dynamics of the microbial population during ripening of Cueva de la Magahá cheese using a combination of classical and molecular techniques. Samples taken during ripening of this Spanish goat's milk cheese in which Lactococcus lactis and Streptococcus thermophilus were used as starter cultures were analyzed. All bacterial isolates were clustered by using randomly amplified polymorphic DNA (RAPD) and identified by 16S rRNA gene sequencing, species-specific PCR, and multiplex PCR. Our results indicate that the majority of the 225 strains isolated and enumerated on solid media during the ripening period were nonstarter lactic acid bacteria, and Lactobacillus paracasei was the most abundant species. Other Lactobacillus species, such as Lactobacillus plantarum and Lactobacillus parabuchneri, were also detected at the beginning and end of ripening, respectively. Non-lactic-acid bacteria, mainly Kocuria and Staphylococcus strains, were also detected at the end of the ripening period. Microbial community dynamics determined by temporal temperature gradient gel electrophoresis provided a more precise estimate of the distribution of bacteria and enabled us to detect Lactobacillus curvatus and the starter bacteria S. thermophilus and L. lactis, which were not isolated. Surprisingly, the bacterium most frequently found using culture-dependent analysis, L. paracasei, was scarcely detected by this molecular approach. Finally, we studied the composition of the lactobacilli and their evolution by using length heterogeneity PCR.     

Screening for potential probiotic from spontaneously fermented non-dairy foods based on in vitro probiotic and safety properties

The aim of this study was to screen potential probiotic lactic acid bacteria from Chinese spontaneously fermented non-dairy foods by evaluating their probiotic and safety properties. All lactic acid bacteria (LAB) strains were identified by 16S rRNA gene sequencing. The in vitro probiotic tests included survival under low pH and bile salts, cell surface hydrophobicity, auto-aggregation, co-aggregation, antibacterial activity, and adherence ability to cells. The safety properties were evaluated based on hemolytic activity and antibiotic resistance profile. The salt tolerance, growth in litmus milk, and acidification ability were examined on selected potential probiotic LAB strains to investigate their potential use in food fermentation. A total of 122 strains were isolated and identified at the species level by 16S rRNA gene sequencing and included 62 Lactobacillus plantarum, 40 Weissella cibaria, 12 Lactobacillus brevis, 6 Weissella confusa, and 2 Lactobacillus sakei strains. One W. cibaria and nine L. plantarum isolates were selected based on their tolerance to low pH and bile salts. The hydrophobicity, auto-aggregation, co-aggregation, and antagonistic activities of these isolates varied greatly. All of the 10 selected strains showed multiple antibiotic resistance phenotypes and no hemolytic activity. The highest adhesion capacity to SW480 cells was observed with L. plantarum SK1. The isolates L. plantarum SK1, CB9, and CB10 were the most similar strains to Lactobacillus rhamnosus GG and selected for their high salt tolerance and acidifying activity. The results revealed strain-specific probiotic properties were and potential probiotics that can be used in the food industry.     

Taxonomic and strain-specific identification of the probiotic strain Lactobacillus rhamnosus 35 within the Lactobacillus casei group

Lactobacilli are lactic acid bacteria that are widespread in the environment, including the human diet and gastrointestinal tract. Some Lactobacillus strains are regarded as probiotics because they exhibit beneficial health effects on their host. In this study, the long-used probiotic strain Lactobacillus rhamnosus 35 was characterized at a molecular level and compared with seven reference strains from the Lactobacillus casei group. Analysis of rrn operon sequences confirmed that L. rhamnosus 35 indeed belongs to the L. rhamnosus species, and both temporal temperature gradient gel electrophoresis and ribotyping showed that it is closer to the probiotic strain L. rhamnosus ATCC 53103 (also known as L. rhamnosus GG) than to the species type strain. In addition, L. casei ATCC 334 gathered in a coherent cluster with L. paracasei type strains, unlike L. casei ATCC 393, which was closer to L. zeae; this is evidence of the lack of relatedness between the two L. casei strains. Further characterization of the eight strains by pulsed-field gel electrophoresis repetitive DNA element-based PCR identified distinct patterns for each strain, whereas two isolates of L. rhamnosus 35 sampled 40 years apart could not be distinguished. By subtractive hybridization using the L. rhamnosus GG genome as a driver, we were able to isolate five L. rhamnosus 35-specific sequences, including two phage-related ones. The primer pairs designed to amplify these five regions allowed us to develop rapid and highly specific PCR-based identification methods for the probiotic strain L. rhamnosus 35.     

Immunomodulating potential of supplementation with probiotics: a dose-response study in healthy young adults

Certain probiotic microorganisms have been found beneficial in the treatment of immune-related diseases and may also affect immune function in healthy people. Intervention studies of probiotics in healthy humans are urgently required. Here, the immunomodulating potential of Bifidobacterium animalis ssp. lactis (BB-12) and Lactobacillus paracasei ssp. paracasei (CRL-431) was studied in a double-blind placebo-controlled parallel dose-response trial (n=71) based on five randomly assigned groups of young healthy adults supplemented for 3 weeks with 0, 10(8), 10(9), 10(10) and 10(11) CFU day(-1), respectively, of a mixture of BB-12 and CRL-431. No statistically significant dose-dependent effect was found for phagocytic activity in blood leukocytes, fecal immunoglobulin A (IgA) concentrations or production of interferon-gamma and interleukin-10 in blood cells. When evaluating data according to the amount of viable BB-12 recovered from faeces, the interferon-gamma production in blood cells was significantly reduced. In conclusion, no solid effect on the immune function of young healthy adults supplemented with even high doses of B. animalis ssp. lactis BB-12 and L. paracasei ssp. paracasei CRL-431 was demonstrated in this study.     

Cholesterol Assimilation by Lactic Acid Bacteria and Bifidobacteria Isolated from the Human Gut

The objective of this study was to evaluate the effect of human gut-derived lactic acid bacteria and bifidobacteria on cholesterol levels in vitro. Continuous cultures inoculated with fecal material from healthy human volunteers with media supplemented with cholesterol and bile acids were used to enrich for potential cholesterol assimilators among the indigenous bacterial populations. Seven potential probiotics were found: Lactobacillus fermentum strains F53 and KC5b, Bifidobacterium infantis ATCC 15697, Streptococcus bovis ATCC 43143, Enterococcus durans DSM 20633, Enterococcus gallinarum, and Enterococcus faecalis. A comparative evaluation regarding the in vitro cholesterol reduction abilities of these strains along with commercial probiotics was undertaken. The degree of acid and bile tolerance of strains was also evaluated. The human isolate L. fermentum KC5b was able to maintain viability for 2 h at pH 2 and to grow in a medium with 4,000 mg of bile acids per liter. This strain was also able to remove a maximum of 14.8 mg of cholesterol per g (dry weight) of cells from the culture medium and therefore was regarded as a candidate probiotic.     

鸡肠源芽胞杆菌的分离、鉴定和抗菌活性

从人工饲养的健康三黄肉鸡的盲肠和大肠中分离出10株芽胞杆菌,对其进行菌落形态观察、革兰染色、芽胞染色和生理生化特性鉴定,确定为枯草芽胞杆菌、地衣芽胞杆菌、蜡状芽胞杆菌、巨大芽胞杆菌、球形芽胞杆菌、短小芽胞杆菌、凝结芽胞杆菌。同时测定了它们对动物病原性大肠埃希菌和链球菌的抑菌活性。其中有9株芽胞杆菌对大肠埃希菌有抑制作用,8株芽胞杆菌对链球菌有抑制作用。结果表明芽胞杆菌分离株Y2、Y3、Y4、Y5、Y6、Y7、Y8具有作为益生菌开发的潜力。     

新疆发酵乳品中乳酸菌的分离鉴定及其耐药性

目的对新疆传统发酵乳品中乳酸菌进行分离鉴定并检测其耐药性。方法利用传统形态学鉴定法和生化鉴定等方法对新疆发酵乳中乳酸菌进行鉴定,采用纸片扩散法对分离鉴定的菌进行耐药性分析。结果从新疆发酵乳品中共分离出8株乳酸菌,经鉴定分别为瑞士乳杆菌(Lactobacillus helveticus)、植物乳杆菌(Lactobacillus plantarum)、马乳酒样乳杆菌(Lactobacillus kefianofaciens)、乳酸乳球菌(Lactococcus lactis)、副干酪乳杆菌(Lactobacillus paracasei)、副干酪乳杆菌类坚韧亚种(Lactobacillus paracasei subsp.tolerans)、哈尔滨乳杆菌(Lactobacillus harbinensis)、希氏乳杆菌(Lactobacillus hilgardii),并且发现8株乳酸菌对万古霉素、庆大霉素、阿莫西林、多西环素、环丙沙星、阿奇霉素、头孢他啶、头孢孟多具有一定敏感性。结论新疆发酵乳品中以乳杆菌居多,对常见抗生素具有一定的敏感性。     

Redox potential to discriminate among species of lactic acid bacteria

AIMS: To verify to what degree reducing capacity is a characterizing parameter of a species, and of the strains themselves within a given species, of lactic acid bacteria. METHODS AND RESULTS: Eighty-eight strains belonging to 10 species of lactic acid bacteria (LAB) isolated from traditional Italian cheeses were studied for their reduction activity: Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, Streptococcus thermophilus, Lactococcus lactis ssp. lactis, Lactobacillus paracasei ssp. paracasei, Lactobacillus plantarum, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus helveticus and Pediococcus pentosaceus. It was observed that the lactococci reached minimum redox potential before the lactobacilli. The reduction rate of Enterococcus spp. and L. lactis ssp. lactis was higher than that of the streptococci and Lactobacillus spp. All the P. pentosaceus strains had poor reduction activity compared with the other species. CONCLUSIONS: The evolution of the redox potential in milk over a time span of 24 h has been found to be a parameter that characterizes a species: the different courses corresponding to the species in question are clearly evident, and interesting differences can also be noted within the same species. SIGNIFICANCE AND IMPACT OF THE STUDY: The reduction aptitude of strains might be used to select and adapt appropriate strains for use as starters for dairy products.     

Probiotic Strains Influence on Infant Microbiota in the In Vitro Colonic Fermentation Model GIS1

The main goal of our study was to evaluate the effect of the individual administration of five lyophilized lactic acid bacteria strains (Lactobacillus fermentum 428ST, Lactobacillus rhamnosus E4.2, Lactobacillus plantarum FCA3, Lactobacillus sp. 34.1, Weissella paramesenteroides FT1a) against the in vitro simulated microbiota of the human colon using the GIS1 system. The influence on the metabolic activity was also assessed by quantitative determination of proteins and polysaccharides at each segment of human colon. The obtained results indicated that the lactic acid bacteria L. rhamnosus E4.2 and W. paramesenteroides FTa1 had better efficiency in synthesising exopolysaccharides and also a better probiotic potential and therefore could be recommended for use in probiotics products or food industry.     

Antimicrobial activity against Shigella sonnei and probiotic properties of wild lactobacilli from fermented food

Four lactobacilli strains (Lactobacillus paracasei subp. paracasei M5-L, Lactobacillus rhamnosus J10-L, Lactobacillus casei Q8-L and L. rhamnosus GG (LGG), were systematically assessed for the production of antimicrobial substances active towards Shigella sonnei, Escherichia coli and Salmonella typhimurium. Agar-well assay showed that the four lactobacilli strains displayed strong antibacterial activity towards S. sonnei. The nature of antimicrobial substances was also investigated and shown to be dependent on the production of organic acids, in particular the lactic acid. Time-kill assay showed that the viability of the S. sonnei was decreased by 2.7-3.6logCFU/ml after contact with CFCS (cell-free culture supernatants) of four lactobacilli for 2h, which confirmed the result of the agar-well assay. Further analysis of the organic acid composition in the CFCS revealed that the content of lactic acid range from 227 to 293mM. In addition, the aggregations properties, adherence properties and tolerance to simulated gastrointestinal conditions were also investigated in vitro tests. The result suggested that the M5-L, J10-L and Q8-L strains possess desirable antimicrobial activity towards S. sonnei and probiotic properties as LGG and could be potentially used as novel probiotic strains in the food industry.     

Butanol production from corncob residue using Clostridium beijerinckii NCIMB 8052

Aims: Not all lactic acid bacteria possess the ability to confer health benefits for the host. Thus, it becomes necessary to screen and characterize numerous strains to obtain ideal probiotics. Here, two Lactobacillus plantarum strains (CECT 7315 and CECT 7316) were isolated and characterized. Methods and Results: In vitro and in vivo tests were carried out for demonstrating the abilities as probiotics of CECT 7315/CECT 7316 Lact. plantarum strains. Both strains showed high ability to survive at gastro‐intestinal tract conditions and to adhere to intestinal epithelial cells, as well as great inhibitory activity against a wide range of enteropathogens and ability to induce the production of anti‐inflammatory cytokine IL‐10. Conclusions: Lactobacillus plantarum CECT 7315/CECT 7316 because of their potential probiotic properties could be excellent candidates for being tested in clinical trials aimed to demonstrate beneficial effects on human health. Significance and Impact of the Study: Probiotics are live micro‐organisms that confer a health benefit for the host. However, not all the lactic acid bacteria possess the ability to confer health benefits for the host. In this study, two Lact. plantarum strains (CECT 7315 and CECT 7316) were isolated and characterized to demonstrate their excellent qualities as potential probiotic strains.     

Selected prebiotics support the growth of probiotic mono-cultures in vitro

The aim of the present study was to identify suitable prebiotics for synergistic combinations with representative probiotics from the lactobacilli and bifidobacterium genera. Eleven different types of commercially available carbohydrates and compounds were screened in basal media for their effects on the growth of the probiotic cultures Lactobacillus acidophilus LAFTI L10 (L10), Bifidobacterium animalis lactis LAFTI B94 (B94) and Lactobacillus casei LAFTI L26 (L26). Growth of these probiotics was investigated by measuring optical density (OD) levels over a period of 48 h. The results of this study showed that all three probiotic strains were able to utilize a range of carbohydrates. Maximal growth of L10 was observed in basal medium supplemented with soybean oligosaccharide (SOS), followed by fructooligosaccharide (FOS) and inulin, while maximal growth of B94 was observed in basal medium supplemented with SOS, followed by raffinose, FOS, beta-glucan hydrolysate, inulin and Fibregum TAN. L26 was shown to exhibit maximal growth in basal medium supplemented with FOS followed by inulin, SOS, beta-glucan hydrolysate and beta-glucan concentrate. The results of this study indicate that several carbohydrates/compounds can enhance the growth of these representative probiotic strains in vitro.