Bile Salt Conditions Research Articles

Incidence of virulence determinants and antibiotic resistance in lactic acid bacteria isolated from food products.

Background: Lactic acid bacteria (LAB) confer beneficial health effects in humans. However, the safety of these bacteria and their potential to spread resistance in the environment must be evaluated. Materials & methods: Fifty-three LAB were isolated from different food samplesand assessed for the prevalence of virulence determinants and antibiotic resistance profile. Results: Multiple resistance was reported for Lactobacillus brevis MIM04, having revealed phenotypic resistance to vancomycin (MIC >128μg/ml), ampicillin, cefotaxime, oxacillin and gentamicin. Virulence traits (cylA, gelE, esp and agg) were detected using specific primers. Enterococcus faecium CHE32, Lactobacillus plantarum CHE37 and E. faecium MLK68lack virulence genes, possess antimicrobial activity andsurvive in low pH and bile salt conditions. Conclusion: Isolated LAB revealed probiotic properties.

Effect of drying methods on Lactobacillus Rhamnosus GG microcapsules prepared using the complex coacervation method.

Lactobacillus rhamnosus GG (LGG) microcapsules prepared using the complex coacervation method were dried through spray and vacuum freeze drying. Physical properties, resistance to simulated gastrointestinal and bile salt conditions, and the stability of the LGG microcapsules during storage and heat treatment were estimated. Spray and vacuum freeze drying are suitable for LGG microcapsule preparation because of lower than 2.80% of the water content, and higher than 93.21% of the encapsulation efficiency. Under the simulated gastrointestinal condition, the survival rates of two kinds of microencapsulated LGG were over 96%. At 0.6% bile salt concentration, the survival rate of microencapsulated LGG subjected to spray drying was 110.89% higher than that of LGG subjected to vacuum freeze drying. In addition, the stability of the former was better than that of the latter during storage under low water activity condition (0.11). However, under high water activity condition (0.75), the two showed opposite results. The two kinds of microencapsulated LGG were completely inactivated after 4weeks in 0.75 of water activity. The survival counts of microencapsulated LGG had no significant difference at -18°C after 8weeks. After 8weeks at 25°C and 4°C, the survival loss of microencapsulated LGG through drying and vacuum freeze drying was approximately 2 and 1 log CFU/g, respectively. PRACTICAL APPLICATION: LGG is a kind of microorganism beneficial to the human body, but it is easy to inactivate and lose its physiological value. LGG microcapsules can improve the stability of LGG, prolong the release time, and expand its application range. The drying method will affect the properties of LGG microcapsules. So, the characteristics analysis of LGG microcapsules with different drying methods can provide a reference for the preparation and application of LGG microcapsules.

Probiotic Potential of Lactobacillus Strains Isolated From Fermented Vegetables in Shaanxi, China.

The objective of this study was to assess in vitro probiotic potential of Lactobacillus strains derived from artisanal fermented vegetables in Shaanxi, China. In total, 74 acid-producing Gram-positive strains with rod-shaped under the microscope were isolated from 16 samples of spontaneously fermented vegetables. Out of 74 strains, 26 showed high survival rate under low pH and high bile salts conditions and were subjected to molecular identification by 16S rRNA gene sequencing analysis. The results showed that 15 isolates belonged to Lactobacillus plantarum, 9 isolates belonged to Lactobacillus brevis, and the 2 remaining strains belonged to Weissella viridescens. The 24 Lactobacillus strains were investigated for their survival rate to transit simulated gastrointestinal tract, cell surface hydrophobicity, auto-aggregation, co-aggregation with pathogen, adhesion to Caco-2, antimicrobial activity, antibiotics susceptibility, radical scavenging ability, α-glucosidase inhibition, and the cholesterol assimilation. The results showed that the probiotic characteristics were strain-dependent, and several strains exhibited great probiotic potential with specific health benefits, which indicated that they might be excellent candidates for production of functional foods. Interestingly, it was first found that L. plantarum generally had higher antibacterial activities, α-glucosidase inhibition ability, and antibiotics susceptibility compared to L. brevis in this study. The results indicated that Lactobacillus strains isolated from fermented vegetables in Shaanxi, China, could be exploited as a promising novel probiotic source.

Cell-free culture supernatants of Lactobacillus spp. and Pediococcus spp. inhibit growth of pathogenic Escherichia coli isolated from pigs in Thailand

BackgroundPathogenic Escherichia coli (E. coli) is an important causative agent for infectious diseases in pigs and causes significant economic loss. The global concern of antimicrobial resistance of bacteria raises awareness of the alternative ways of using antimicrobial peptides (AMPs). The study was aimed to identify and test the efficacy of AMPs from Lactobacillus spp. against the growth of pathogenic E. coli isolated from pigs in Thailand. Briefly, cell-free culture supernatants (CFCS) from 3 strains of lactic acid bacteria (LAB) consisting of Lactobacillus acidophilus (strain KMP), Lactobacillus plantarum (strain KMP), and Pediococcus pentosaceus (strain KMP) were tested against pathogenic E. coli via agar well diffusion assay in quadruplicates. The presence of a zone of inhibition (ZOI) around wells was evaluated at different incubation time. Acid and bile tolerance test was performed for bacterial viability in acid and bile salt conditions. In addition, LAB cross-streaking assay was evaluated for antagonist activity.ResultsThe study showed that CFCS from L. acidophilus KMP, L. plantarum KMP, and P. pentosaceus KMP could inhibit the growth of pathogenic E. coli isolated from pigs in a time-dependent manner. To exemplify, the ZOI of L. plantarum KMP against E. coli (ETEC) at 8, 10, 12, 14, and 16 h incubation, were 26.6 ± 1.1, 24.9 ± 1.9, 22.5 ± 2.4, 20.3 ± 2.9, and 17.9 ± 3.3 mm, respectively. The ZOI was significantly different between 8, 10, 12, 14 h incubation, and the ZOI of the CFCS from L. plantarum KMP was larger than others (P-value < 0.05). Furthermore, L. acidophilus KMP, L. plantarum KMP, and P. pentosaceus KMP showed viability in pH 3.0, 0.3, and 0.5% (w/v) bile salt concentration. They exhibited no antagonist activity among each other.ConclusionsAccording to the results, the CFCS from LAB including L. acidophilus KMP, L. plantarum KMP and P. pentosaceus KMP can inhibit the growth of pathogenic E. coli, isolated from pigs in Thailand. The antimicrobial activity observed was incubation time dependent.

Effects of the Probiotic Lactiplantibacillus plantarum KU15120 Derived from Korean Homemade Diced-Radish Kimchi Against Oxidation and Adipogenesis.

Intestinal microflora can influence abnormal adipocyte growth. Therefore, this study was aimed to investigate the probiotic properties and antioxidant and antiobesity effects of isolated strains from homemade kimchi. Among the isolated strains, Lactiplantibacillus plantarum KU15120 showed high tolerance to artificial gastric juice and bile salt conditions, high adhesion to HT-29 cells, nonproduction of β-glucuronidase, nonhemolysis, and acceptable resistance to antibiotics. It showed high antioxidant activity, including DPPH and ABTS radical scavenging and antioxidant activity, as determined by the β-carotene bleaching assay. Oil red O staining and intracellular triglyceride levels revealed reduced lipid accumulation, which confirmed the anti-adipogenic activity of L. plantarum KU15120. In addition, the expression levels of fatty acid synthase, CCAAT/enhance-binding proteinα, and peroxisome proliferator-activated receptorγ, were significantly lower in the probiotic-treated group than in the control group. These results suggest that L. plantarum KU15120 has probiotic properties, antioxidant, and antiobesity effects and could be used as a therapeutic probiotics.

Characterization of Streptococcus salivarius as New Probiotics Derived From Human Breast Milk and Their Potential on Proliferative Inhibition of Liver and Breast Cancer Cells and Antioxidant Activity.

Breast milk is well known as the abundant source of beneficial bacteria. A new alternative source of human probiotic origin from breast milk is in demand and currently of interest for both the functional food industry and biopharmaceuticals. The aim in this study was to investigate the anticancer and antioxidant efficacies of the new potential probiotics isolated from human breast milk. Three strains of lactic acid bacteria (LAB) have shown their potential probiotic criteria including antimicrobial activity, non-hemolytic property, and survival in acid and bile salt conditions. These strains showed high abilities on cell surface hydrophobicity, auto-aggregation, and co-aggregation. The genera identification by 16S rRNA sequencing and comparison revealed that they were Streptococcus salivarius BP8, S. salivarius BP156, and S. salivarius BP160. The inhibition of liver cancer cells (HepG2) and breast cancer cells (MCF-7) proliferation by these probiotic strains using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was 44.83–59.65 and 29.85–37.16%, respectively. The probiotic action mode was inducted via apoptotic mechanisms since they stimulate the liver and breast cancer cell death through DNA fragmentation and positive morphological changes by acridine orange (AO) and propidium iodide (PI) staining. The antioxidant activity of these probiotics in the form of intact cells, cell free supernatant (CFS), and heat-killed cells was evaluated by a 2,2–diphenyl–1–picrylhydrazyl (DPPH) assay, resulting in the scavenging activity rates of 16.93–25.43, 15.47–28.03, and 13.67–23.0%, respectively. These S. salivarius probiotic strains protected the L929 mouse fibroblasts against oxidative stress with very high survival rates at 94.04–97.77%, which was significantly higher (P < 0.05) than L-ascorbic acid at 75.89–78.67% in the control groups. The results indicated that S. salivarius BP8 and S. salivarius BP160 probiotic strains could be applied as functional foods or new alternative bioprophylactics for treating liver and breast cancers.

Development of pelleted feed containing probiotic Lactobacillus rhamnosus GG and Jerusalem artichoke for Nile Tilapia and its biocompatibility studies.

Growth performance and immune systems of tilapias could be improved by Lactobacillus rhamnosus GG (LGG) and Jerusalem artichoke. This research aimed to determine the effects of Jerusalem artichoke on LGG viability after drying and pelleting and their subsequent exposure to simulated gastrointestinal conditions. Fresh LGG cells were added into wall material solutions, including alginate (AL), alginate + milk powder (AM), and alginate + milk powder + Jerusalem artichoke at different concentrations (AMJ). The solutions were then spray dried to obtain LGG powders. The powder with the highest cell number was then selected to mix with tilapia feed mash and pelleted using a nonthermal feed extruder to obtain pelleted feed containing LGG and Jerusalem artichoke. The LGG viability spray dried powders and pelleted feed were analyzed for their cell counts after drying and after exposure to simulated gastrointestinal conditions. The result showed that the number of viable cells in AMJ was significantly higher than AM and AL after drying. The number of viable cells under both simulated gastric and bile salt fluids was improved with the increasing of Jerusalem artichoke concentrations. The number of viable cells after pelleting process could be maintained. LGG in the pelleted feed could also survive under the simulated gastric and bile salt conditions. The study indicates that JA enhanced LGG viability after drying and exposure to simulated gastrointestinal conditions. The pelleted feed containing LGG and Jerusalem artichoke could be applied in tilapia farming, providing convenience to the farmers, and valuable effects to the fish.

Application of Tarkhineh Fermented Product to Produce Potato Chips With Strong Probiotic Properties, High Shelf-Life, and Desirable Sensory Characteristics.

The application of Tarkhineh texture to protect probiotics in potato chips has been investigated as the main goal in this paper. In this study, the probiotic assessments, morphological characteristics, sensory evaluation, and survival rates of the covered probiotic cells with Tarkhineh in potato chips during storage time were assessed. Based on results, T34 isolated from traditional Tarkhineh as a safe strain had a high tolerance to low pH and bile salt conditions, displayed acceptable anti-pathogenic activities, and also showed desirable antibiotic susceptibility. Two types of Tarkhineh formulations (plain Tarkhineh and turmeric Tarkhineh) were applied using a simple spraying method for covering T34 cells in potato chips. All formulations showed elliptical to spherical (480-770 μm) shape probiotic drops. Storage stability results revealed that T34 cells mixed with turmeric and plain Tarkhineh during 4 months of storage at 4°C displayed excellent protection abilities with about 3.70 and 2.85 log decreases in CFU/g respectively. Additionally, probiotic potato chips compared to non-probiotic and commercial potato chips, exhibited probiotic product criteria such as excellent quality and superior sensory properties during storage time. In conclusion, Tarkhineh showed high potential as a protective matrix for probiotic cells in potato chips.

Comparison of functional characteristics of distinct Saccharomyces boulardii strains isolated from commercial food supplements

Saccharomyces boulardii is a probiotic yeast with several health benefits. An important number of products are available in the market claiming to contain probiotic S. boulardii strains and these numbers are increasing. In this study, S. boulardii strains were isolated from commercial products, identified and characterised in terms of several probiotic features. Eleven distinct S. boulardii strains were identified by genotypic tests followed by FT-IR spectroscopy and biochemical analysis which were used to differentiate S. boulardii strains from other yeasts including Saccharomyces cerevisiae. All tested strains showed high level of survival under harsh conditions and auto-aggregation characteristics. The hydrophobicity of S. boulardii strains revealed strain specific features and only two strains survived at pH of 2.5. A high level of survival under bile salts conditions were observed for all tested strains. Distinct S. boulardii strains were found to be resistant to bacterial antibiotics whereas they were sensitive to fungal antibiotics. Finally, S. boulardii strains showed high level of antibacterial and antifungal activities particularly against Salmonella Typhimurium and Aspergillus niger, respectively. This study revealed the differences in the functional characteristics of S. boulardii strains available in the market.

AISLAMIENTO E IDENTIFICACIÓN DE Lactobacillus spp. (LACTOBACILLACEAE) RESISTENTES A Cd(II) Y As(III) RECUPERADOS DE FERMENTO DE CACAO

El objetivo de este estudio fue aislar e identificar a partir de cacao fermentado en Caldas Colombia, bacterias con potencial de aplicación en procesos biotecnológicos, como la detoxificación de cadmio (Cd(II)) y arsénico (As(III)) en el organismo humano. En total se recuperaron 36 aislados de los cuales se recuperaron 11 en presencia de 1,0 mg/L de Cd(II) y 25 en presencia de 0,1 mg/L de As(III). Su identificación molecular determinó que la mayoría de los aislados son del género Lactobacillus. Los ensayos de crecimiento en presencia de diferentes concentraciones de los elementos evaluados permitió determinar que gran parte de los aislamientos presentan resistencia a mayores concentraciones de As(III) (300 mg/L) que de Cd(II) (10 mg/L). En ensayos de tolerancia a la acidez (pH 2,5) se encontró que la cepa tipo Lactobacillus plantarumJCM 1055, junto con los aislamientos nativos L. plantarumA19, A26 y C16, mostraron la mayor tolerancia, por lo que se seleccionaron para evaluar su tolerancia a condiciones de salinidad. Las bacterias evaluadas mostraron crecimiento en concentraciones de hasta 4 g/L de sales biliares. Se concluye que los L. plantarumevaluados en este trabajo tienen un gran potencial para futuros ensayos en los que se busque demostrar la disminución de la bioaccesibilidad de Cd(II) y As(III) en condiciones in vitro del sistema digestivo humano debido a su resistencia a altas concentraciones de estos elementos y su tolerancia a condiciones de acidez y salinidad. Esto, junto con el reconocido potencial probiótico que tienen estos microorganismos, permitirá a futuro su uso en procesos biológicos de mitigación de Cd(II) y As(III).

A Multi-Scale Approach to Investigate Adhesion Properties of Pseudomonas aeruginosa PAO1 to Geotrichum candidum LG-8, a Potential Probiotic Yeast.

This study investigated properties of Pseudomonas aeruginosa PAO1 adhesion to Geotrichum candidum LG-8 cells in variable pH and salt conditions. The primary mechanism was revealed by multi-scale microscopy technics. The adhesion of PAO1 to the living fungus occurred within 1 h and was limited at concentrations of bile salts higher than 0.5%. The adhesion efficiency gradually increased to 58.1% with the pH increasing from 2.0 to 7.0 and then decreased to 48.2% at pH 9.0. However, the dead LG-8 has an advantage over the living ones to adhere PAO1 in same pH and bile salt conditions. Optical microscopy showed that both unsterilized and sterilized G. candidum LG-8 cells removed approximately one hundred fold bacteria in 4 h. Laser scanning confocal microscopy (LSCM) analysis indicated that polysaccharides of the fungus contributed to adhesion. Scanning electron microscopy (SEM) analysis proved that syrup-like EPS (extracellular polymeric substances) of LG-8 coating PAO1 was in part a mechanism. Atomic force microscopy (AFM) showed roughness of the LG-8 surface changed in the adhesion process. Furthermore, a pedestal-like structure of bacteria was observed by transmission electron microscopy (TEM) analysis, indicating that the bacteria were also actively involved in the adhesion process. G. candidum LG-8 is a potential candidate for the control of P. aeruginosa PAO1 in the food industry and immunodeficiency patients.

Using Potential Lactic Acid Bacteria Biofilms and their Compounds to Control Biofilms of Foodborne Pathogens

Pediococcus pentosaceus and Enterococcus faecium isolated from fermented fish and chicken represented the potential probiotic properties against Bacillus cereus ATCC 11778, Escherichia coli ATCC 8739, and Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311. Isolated Lactic Acid Bacteria were tested for physiological characteristics, antimicrobial activity of crude supernatant containing 0.5- 1.3% w/ v nisin against planktonic and biofilm of foodborne pathogens, biofilm forming ability, auto-aggregation, co-aggregation with all tested pathogens, bacterial survival in acid and bile salt conditions, hemolytic activity, and minimal inhibitory concentration of antibiotics. Isolates were also identified using 16S rRNA sequencing. LAB showed antimicrobial activities against planktonic and biofilm forms of all tested foodborne pathogens. All LAB could develop biofilms to prevent biofilm formations of all tested pathogens through the co-aggregation process. They showed 6-8% tolerance to bile salt, were partially resistant to low pH, hemolysis negative, and antibiotic susceptibility to the level allowed by European Food Safety Authority.

Antioxidant and Anti-Inflammatory Effect of Probiotic Lactobacillus plantarum KU15149 Derived from Korean Homemade Diced-Radish Kimchi.

Lactobacillus plantarum KU15149 was demonstrated to have probiotic behavior and functions, including antioxidant and anti-inflammatory activity. L. plantarum KU15149 obtained from homemade diced-radish kimchi has a high survival rate under artificial gastric acid (pH 2.5, 0.3% pepsin) and bile salt (0.3% oxgall) conditions. However, L. plantarum KU15149 did not produce β-glucuronidase, which is known to be a carcinogenic enzyme with resistance to several antibiotics, such as gentamycin, kanamycin, streptomycin, tetracycline, and ciprofloxacin. L. plantarum KU15149 strongly adhered to HT-29 cells and had high antioxidant activity in terms of 2,2-diphenyl- 1-picrylhydrazyl (DPPH) free radical-scavenging and β-carotene bleaching assays. L. plantarum KU15149 also exhibited a pronounced inhibition of nitric oxide (NO) production, along with expression of nitric oxide synthase (iNOS) and cyclooxygenase -2 (COX-2) as well as proinflammatory cytokines, such as TNF-α, IL-1β, and IL-6, when RAW 264.7 cells were stimulated with LPS. Therefore, L. plantarum KU15149 exhibited pharmaceutical functionality as a potential probiotic.

Identification and selection of yeast with functional properties for future application in soft paste cheese

This study investigated the yeast community in traditional soft cheese from the Extremadura region to be able to establish possible beneficial properties for human health. A total of 149 yeast isolates were characterised at strain level using the ISSR-PCR technique with the primer (GTG)5. Forty-three different genetic profiles were obtained, and the yeasts were grouped into 12 species allowing their typification at strain level. Regarding probiotic tests, 54 strains were selected for the study of probiotic properties based on genetic profile and origin. All of them showed adequate tolerance to the most restrictive stomach and bile salts conditions, although strains of Kluyveromyces lactis and Pichia fermentans presented better ability to survive to these stresses. P. fermentans was also the species that showed better antioxidant, auto-aggregation and hydrophobicity capacity, at the same time as antimicrobial activity, followed by Kluyveromyces sp. strains. Thus, considering the probiotic characteristics studied, 15 strains, P. fermentans 1826, 1865, 1859, 1911,1913, 1916 and 1938; P. kudriavzevii 1801, 1809 and 1832; K. marxianus 1886, 1917 and 1919; D. hansenii 1860; and Y. lipolytica 1961, are promising potential probiotic candidates for developing a functional cheese.

PROBIOTIC PROPERTIES AND ANTIOXIDANT EFFICIENCY OF LACTOBACILLUS PLANTARUM 15 ISOLATED FROM MILK

Many researchers are focusing on the investigation of new molecules and substances to help the body fighting oxidative stress; among them are probiotic bacteria. In this study we investigated the probiotic properties and the antioxidative activity of Lactobacillus plantarum 15 isolated from milk. Therefore, to evaluate probiotic potential of the selected strain, the antibacterial activity and resistance to acidic pH and bile salts conditions were evaluated. Moreover, several methods were used to analyze the antioxidant potential of this strain. The evaluation of probiotic properties showed that Lb. plantarum 15 resists to acidity and to bile salts (survival rate was 86.40% and 80.58%, respectively). The isolate showed a broad inhibitory activity against several bacterial strains. The antioxidant potential assessed by the DPPH method showed that Lb. plantarum 15 cells as well as the cell-free supernatant have important scavenger effect (82.65% and 72.21%, respectively). Furthermore, the strain showed a good resistance to hydrogen peroxide (76.12%), hydroxyl radicals (46.15%) and a considerable iron chelating ability (20.52 %). Thus, Lb. plantarum 15 could be effectively considered as potent antioxidant probiotic food supplement.

The Assays of Bacteria-Yeast Consortia as Probiotics Candidates and Their Influences on Nutrients Utilization of Quails Diet

This study aimed to assay L. plantarum (P1), S. cerevisiae (P2), and its combination (P3) as probiotics candidates and their effects on nutrient digestibility in Japanese quails (Cortunix cortunix japonica) diets. In vitro assays were employed to evaluate the antibacterial activities against pathogenic bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella pullorum), sensitivity to antibiotics (i.e., streptomycin, penicillin, and erythromycin), stress on bile salt and acidity condition. Evaluation of probiotics on in vivo nutrient utilization was carried out by administration of probiotics to laying quails in drinking water with various treatments (R0, control; R1, L. plantarum; R2, S. cerevisiae; R3, combination of R1+R2; R4, commercial feed additive). Results showed that the highest inhibitory activity was performed by P2 on S. aureus (17.28 mm). Treatments P2 and P3 were resistant to all the tested antibiotics, while P1 was resistant to streptomycin and penicillin. P1 was tolerant to bile salts whereas P2 was tolerant to gastric acidity conditions. For the in vivo experiment, quails fed R1, R2, and R4 had higher nitrogen retention as compared to R0 (p<0.05). However, all treatments revealed similar metabolizable energy values. The cluster analysis showed that quails consuming the combination of L. plantarum and S. cerevisiae were within the same cluster with the control but different clusters from the individual probiotics across all parameters, indicating a possible antagonistic effect between the two species. In conclusion, the inclusion of L. plantarum or S. cerevisiae inhibits pathogenic bacteria without influencing nutrient utilization of quail diet.

An Investigation of PS-b-PEO Polymersomes for the Oral Treatment and Diagnosis of Hyperammonemia.

Ammonia-scavenging transmembrane pH-gradient poly(styrene)-b-poly(ethylene oxide) polymersomes are investigated for the oral treatment and diagnosis of hyperammonemia, a condition associated with serious neurologic complications in patients with liver disease as well as in infants with urea cycle disorders. While these polymersomes are highly stable in simulated intestinal fluids at extreme bile salt and osmolality conditions, they unexpectedly do not reduce plasmatic ammonia levels in cirrhotic rats after oral dosing. Incubation in dietary fiber hydrogels mimicking the colonic environment suggests that the vesicles are probably destabilized during the dehydration of the intestinal chyme. The findings question the relevance of commonly used simulated intestinal fluids for studying vesicular stability. With the encapsulation of a pH-sensitive dye in the polymersome core, the local pH increase upon ammonia influx could be exploited to assess the ammonia concentration in the plasma of healthy and cirrhotic rats as well as in other fluids. Due to its high sensitivity and selectivity, this polymersome-based assay could prove useful in the monitoring of hyperammonemic patients and in other applications such as drug screening tests.

Assessment of Probiotic Properties of Lactic Acid Bacteria from Traditional Sourdoughs for Bread-Making in Turkey against Some Gut Conditions

This study aims to assess the probiotic properties of Lactic Acid Bacteria isolated from the traditional sourdoughs used for bread making in Turkey against some gut conditions. A total number of 29 samples from twelve provinces of Turkey were collected, and screened for the presence of lactic acid bacteria using microbiological methods. The microbiological screening yielded 148 presumptive isolates. Of them, 62.8% were characterized as lactic acid strains by VITEK® MS. Following that, the characterized isolates were subjected to probiotic property testing, including gastric acid resistance, bile resistance and hydrophobic ability. The results showed that 44.1% exceeded gastric pH resistance, 33.3% survived under gastrointestinal system bile salt conditions, and 10.8% exhibited high hydrophobicity ability. In conclusion, our study revealed that only 4.3% (1 Enterococcus faecium, 1 Lactobacillus brevis, 1 Lactobacillus pentosus, and 1 Lactobacillus plantarum) out of 93 lactic acid bacteria isolated from the traditional sourdoughs could meet all probiotic requirements against some gut conditions.

Isolation and Characterization of Lactobacillus spp. from Kefir Samples in Malaysia.

Kefir is a homemade, natural fermented product comprised of a probiotic bacteria and yeast complex. Kefir consumption has been associated with many advantageous properties to general health, including as an antioxidative, anti-obesity, anti-inflammatory, anti-microbial, and anti-tumor moiety. This beverage is commonly found and consumed by people in the United States of America, China, France, Brazil, and Japan. Recently, the consumption of kefir has been popularized in other countries including Malaysia. The microflora in kefir from different countries differs due to variations in culture conditions and the starter media. Thus, this study was aimed at isolating and characterizing the lactic acid bacteria that are predominant in Malaysian kefir grains via macroscopic examination and 16S ribosomal RNA gene sequencing. The results revealed that the Malaysian kefir grains are dominated by three different strains of Lactobacillus strains, which are Lactobacillus harbinensis, Lactobacillusparacasei, and Lactobacillus plantarum. The probiotic properties of these strains, such as acid and bile salt tolerances, adherence ability to the intestinal mucosa, antibiotic resistance, and hemolytic test, were subsequently conducted and extensively studied. The isolated Lactobacillus spp. from kefir H maintained its survival rate within 3 h of incubation at pH 3 and pH 4 at 98.0 ± 3.3% and 96.1 ± 1.7% of bacteria growth and exhibited the highest survival at bile salt condition at 0.3% and 0.5%. The same isolate also showed high adherence ability to intestinal cells at 96.3 ± 0.01%, has antibiotic resistance towards ampicillin, penicillin, and tetracycline, and showed no hemolytic activity. In addition, the results of antioxidant activity tests demonstrated that isolated Lactobacillus spp. from kefir G possessed high antioxidant activities for total phenolic content (TPC), total flavonoid content (TFC), ferric reducing ability of plasma (FRAP), and 1,1-diphenyl-2-picryl-hydrazine (DPPH) assay compared to other isolates. From these data, all Lactobacillus spp. isolated from Malaysian kefir serve as promising candidates for probiotics foods and beverage since they exhibit potential probiotic properties and antioxidant activities.

Effects of Lactococcus lactis from Cyprinus carpio L. as probiotics on growth performance, innate immune response and disease resistance against Aeromonas hydrophila

In the present study, we reported 18 LAB strains isolated from the intestinal contents of Cyprinus carpio, and their probiotic properties both in vitro and in vivo. The results showed that 9 of them had higher in vitro immunomodulatory properties, effectively survived under acidic (pH 2.5) and bile salt (ranging from 0.1% to 0.5%) conditions, and inhibited the growth of 4 pathogens. Among them, Lactococcus lactis Q-8, Lactococcus lactis Q-9, and Lactococcus lactis Z-2 showed the strongest adhesion abilities and inhibition of pathogen adhesion to mucin. When the fish consumed diets containing these 3 strains (5 × 108 CFU/g) for 8 weeks, the weight gain (WG) and specific growth rate (SGR) had significantly (P < 0.05) increased, especially with L. lactis Q-8, which had a WG of 231.45%, and SGR of 2.22%. Survival rate in each LAB supplementation group was also significantly higher than that in control group during the feeding period (P < 0.05). For the cytokines expression levels in serum, different expression patterns were also observed. Before the infection with Aeromonas hydrophila, L. lactis supplementation significant up-regulated protein levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-12) compared with negative (CK1) group, while these cytokines were significantly lower than those in positive (CK2) group after infection. However, whether infected or not, the expression of anti-inflammatory cytokines (IL-10, TGF-β) were significantly increased in L. lactis Q-8, L. lactis Q-9, and L. lactis Z-2 treatment groups. In conclusion, these 3 L. lactis strains screened from common carp were effective in improving growth, innate immunity and disease resistance. Based on the physiological characteristics in our study, they might be used as potential probiotics in aquaculture.