Bifidobacterium-selective isolation and enumeration from chicken caeca by a modified oligosaccharide antibiotic-selective agar medium

Toward Renewable-Based Prebiotics from Woody Biomass: Potential of Tailored Xylo-Oligosaccharides Obtained by Enzymatic Hydrolysis of Beechwood Xylan as a Prebiotic Feed Supplement for Young Broilers

Although antibiotic resistance emerges naturally, this process has been accelerated by the worldwide overuse and misuse of antibiotics. It is essential to find effective alternatives in the broiler industry to improve poultry health while maintaining production efficiency and product safety. In this study, we aimed to evaluate a potential alternative: wood-derived xylo-oligosaccharides (XOS). The objective of this research was to investigate the potential of XOS prepared using enzymatic hydrolysis of beechwood xylan as a prebiotic feed supplement for broilers. A pilot study was conducted to explore the optimal XOS fraction profile by in vitro fermentation. Subsequently, a semi-continuous enzyme membrane reactor was used, allowing for the production of tailored XOS in large quantities. Given the strong bidirectional relationship between intestinal health, nutrition, and intestinal microbiota composition in broilers, an in vivo experiment was performed to explore the potential of XOS as a prebiotic feed supplement by investigating growth performance, feed conversion ratio, caecal short and medium chain fatty acid (SCFA and MCFA) concentration, and microbiological composition of the caecal content. Results from the pilot study indicated that higher enzyme concentrations in the hydrolysis process yield a product that leads to a higher total SCFA and MCFA- and butyric acid production during in vitro fermentation by caecal bacteria. Supplementation of the tailored XOS to the broiler diet (day 1 (d1)-d8 0.13% wt/wt XOS, d9-d15 0.32% XOS) resulted in higher Bifidobacterium counts, beneficial to the health of birds, on d11 and d15.

Biodiversity of Lactobacillus helveticus isolates from dairy and cereal fermentations reveals habitat-adapted biotypes

For the present study, we collected 22 Lactobacillus helveticus strains from different dairy (n = 10) and cereal (n  = 12) fermentations to investigate their biodiversity and to uncover habitat-specific traits. Biodiversity was assessed by comparison of genetic fingerprints, low-molecular-weight subproteomes, metabolic and enzymatic activities, growth characteristics and acidification kinetics in food matrices. A clear distinction between the dairy and cereal strains was observed in almost all examined features suggesting that the different habitats are domiciled by different L. helveticus biotypes that are adapted to the specific environmental conditions. Analysis of the low-molecular-weight subproteome divided the cereal isolates into two clusters, while the dairy isolates formed a separate homogeneous cluster. Differences regarding carbohydrate utilization were observed for lactose, galactose, sucrose and cellobiose as well as for plant-derived glucosides. Enzymatic differences were observed mainly for ß-galactosidase and ß-glucosidase activities. Further, growth temperature was optimal in the range from 33 to 37°C for the cereal strains, whereas the dairy strains showed optimal growth at 40°C. Taken together, adaptation of the various biotypes results in a growth benefit in the particular environment. Acidification and growth tests using either sterile skim milk or a wheat flour extract confirmed these results. Differentiation of these biotypes and their physiological characteristics enables knowledge-based starter culture development for cereal versus dairy products within one species.

Development of a Rapid Method for the Screening of Conjugated Linoleic Acid (CLA)-Producing Strains of Bifidobacterium breve

This study was performed to isolate some strains of Bifidobacteriumbreve from fecal materials of neonates and to screen them for the biotransformation activity of converting linoleic acid into conjugated linoleic acid (CLA). Fecal samples were collected from twenty healthy neonates between 14 and 100 days old, and four hundred colonies were randomly selected from a Bifidobacterium selective transoligosaccharide medium. A duplex polymerase chain reaction technique was developed for the rapid and accurate molecular characterization of the B. breve strains that have been reported to show the species-specific characteristic of CLA production. They are identified by 16S ribosomal DNA, fructose-6-phosphate phosphoketolase encoding genes (xfp), and rapid pulsed field gel electrophoresis. Thirty-six isolates were identified as B. breve, and just two of the 12 neonates were harboring B. breve strains. Each isolate showed different CLA-producing ability in the spectrophotometric assay. All of the positive strains from the primary spectrophotometric assay were confirmed for their CLA-producing activities using gas-chromatographic analysis, and their conversion rates were different, depending on the strain isolated in this study. Some strains of B. breve were successfully isolated and characterized based on the CLA-producing activity, and further studies are necessary to characterize the enzyme and the gene responsible for the enzyme activity.

Characteristics of Kwark Cheese Supplemented with Bifidobacterium longum KACC 91563

The effect of addition of the probiotic Bifidobacterium longum KACC 91563 on the chemical and sensory properties of Kwark cheese produced using CHN-11 as a cheese starter were investigated. The addition of B. longum KACC 91563 to Kwark cheese did not change the composition or pH value of the cheese, compared with control. B. longum KACC 91563 survived at a level of 7.58 Log CFU/g and did not have any negative effect on survival of the cheese starter. A sensory panel commented that the addition of B. longum KACC 91563 made Kwark cheese more desirable to consumers, and that the probiotic supplementation had no effect on perceived taste. Thus, B. longum KACC 91563 can be used for inclusion of probiotic bacteria in cheese.

EFFECTS OF PROBIOTIC INTAKE ON INTESTINAL BIFIDOBACTERIA OF CELIAC PATIENTS

BACKGROUND

Healthy individuals exhibit a significantly higher concentration of faecal bifidobacteria in comparison to celiac patients. Even though there are potential benefits in probiotic usage, they have been little explored as an adjunctive therapy in celiac disease.

OBJECTIVE

This study aimed at the comparison of faecal bifidobacteria concentration and pH among celiac patients and healthy subjects before and after the daily intake of 100 g of yogurt containing probiotic for a thirty-day period.

METHODS

Feces from 17 healthy subjects and 14 celiac patients were analyzed, in which stool culture was performed for the isolation and quantification of faecal bifidobacteria. Furthermore, Gram's method was employed for the microscopic analysis of the colonies, while the identification of the Bifidobacterium genus was made through determination of the fructose-6-phosphate phosphoketolase enzyme. Faecal pH was measured using a calibrated pHmeter.

RESULTS

Faecal bifidobacteria concentration before probiotic consumption was significantly higher in healthy individuals (2.3x108±6.3x107 CFU/g) when compared to celiac patients (1.0x107±1.7x107 CFU/g). Faecal pH values did not show a significant difference. After the daily consumption of probiotic-containing yogurt both groups showed a significant increase in the concentration of faecal bifidobacteria, but healthy subjects presented significantly higher bifidobacteria concentrations (14.7x108±0.2x108 CFU/g) than the celiac group (0.76x108±0.1x108 CFU/g). The obtained pH values from both groups were not significantly different, being 7.28±0.518 for the celiac patients and 7.07±0.570 for healthy individuals after the probiotic intake.

CONCLUSION

The probiotic supplementation significantly increased the number of bifidobacteria in the feces of celiac patients, although it was not sufficient to reach the concentration found in healthy individuals prior to its consumption.

Anaerobic Probiotics: The Key Microbes for Human Health

Human gastrointestinal microbiota (HGIM) incorporate a large number of microbes from different species. Anaerobic bacteria are the dominant organisms in this microbial consortium and play a crucial role in human health. In addition to their functional role as the main source of many essential metabolites for human health, they are considered as biotherapeutic agents in the regulation of different human metabolites. They are also important in the prevention and in the treatment of different physical and mental diseases. Bifidobacteria are the dominant anaerobic bacteria in HGIM and are widely used in the development of probiotic products for infants, children and adults. To develop bifidobacteria-based bioproducts, therefore, it is necessary to develop a large-scale biomass production platform based on a good understanding of the ideal medium and bioprocessing parameters for their growth and viability. In addition, high cell viability should be maintained during downstream processing and storage of probiotic cell powder or the final formulated product. In this work we review the latest information about the biology, therapeutic activities, cultivation and industrial production of bifidobacteria.

Anticlostridial agent 8-hydroxyquinoline improves the isolation of faecal bifidobacteria on modified Wilkins-Chalgren agar with mupirocin

The need for suitable selective cultivation media for the isolation of Bifidobacterium spp. continues to be a real concern in the field of intestinal microbiology. Isolation of bifidobacteria from human and animal faecal samples using selective agar plating may be problematic especially in samples with increased clostridial counts than bifidobacterial counts. Due to the absence of anticlostridial agents in existing selective media, clostridia can displace bifidobacteria resulting in incorrect estimation of their counts. Therefore, we supplemented the existing selective medium 'modified Wilkins Chalgren agar with mupirocin' (MWM) with 90 mg l(-1) of 8-hydroxyquinoline (8HQ), which was recently proved to act selectively against clostridia. The newly composed 'modified Wilkins-Chalgren agar with 8HQ' (MWMQ) was tested on pure bifidobacterial and clostridial strains, their mixtures, and using faecal samples of mammalian origin; its selectivity was evaluated by genus-specific identification of isolates. The results demonstrated that the presence of 8HQ in this agar eliminated the growth of nonbifidobacterial strains on MWMQ compared to that on MWM, whereas the recovery of bifidobacterial counts was at satisfactory levels. In conclusion, MWMQ could be recommended for bifidobacterial isolation from human and animal faeces especially when bifidobacteria are not numerically dominant and there are chances of clostridial contamination.

SIGNIFICANCE AND IMPACT OF THE STUDY

Routine isolation of bifidobacteria from mammalian faeces does not use a reliable selective agar with an anticlostridial agent. Overgrowth of clostridia may result in incorrect estimation of bifidobacterial counts. Thus, in order to improve the selectivity of existing media for bifidobacterial isolation, we chose the modified Wilkins-Chalgren agar with mupirocin and supplemented it with 8-hydroxyquinoline (8HQ), a molecule that shows anticlostridial activity without affecting the growth of bifidobacteria. This newly composed medium showed enhanced selectivity and specificity compared to the original medium and therefore, can be recommended for the isolation of bifidobacteria from mammal faeces.

The anti-diabetic activity of Bifidobacterium lactis HY8101 in vitro and in vivo

AIMS

The aim of this study was to evaluate the effects of Bifidobacterium lactis HY8101 on insulin resistance induced using tumour necrosis factor-α (TNF-α) in rat L6 skeletal muscle cells and on the KK-A(Y) mouse noninsulin-dependent diabetes mellitus (NIDDM) model.

METHODS AND RESULTS

The treatment using HY8101 improved the insulin-stimulated glucose uptake and translocation of GLUT4 via the insulin signalling pathways AKT and IRS-1(Tyr) in TNF-α-treated L6 cells. HY8101 increased the mRNA levels of GLUT4 and several insulin sensitivity-related genes (PPAR-γ) in TNF-α-treated L6 cells. In KK-A(Y) mice, HY8101 decreased fasting insulin and blood glucose and significantly improved insulin tolerance. HY8101 improved diabetes-induced plasma total cholesterol and triglyceride (TG) levels and increased the muscle glycogen content. We observed concurrent transcriptional changes in the skeletal muscle tissue and the liver. In the skeletal muscle tissue, the glycogen synthesis-related gene pp-1 and GLUT4 were up-regulated in mice receiving HY8101 treatment. In the liver, the hepatic gluconeogenesis-regulated genes (PCK1 and G6PC) were down-regulated in mice receiving HY8101 treatment.

CONCLUSIONS

Bifidobacterium lactis HY8101 can be used to moderate glucose metabolism, lipid metabolism and insulin sensitivity in mice and in cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bifidobacterium lactis HY8101 might have potential as a probiotic candidate for alleviating metabolic syndromes such as diabetes.

Bifidobacterium faecale sp. nov., isolated from human faeces

A novel strain, designated strain CU3-7(T), was isolated from faeces of a two-week-old baby. The isolate was Gram-staining-positive, anaerobic and rod-shaped. Results from 16S rRNA gene sequence analysis revealed that strain CU3-7(T) was phylogenetically affiliated with members of the genus Bifidobacterium. Strain CU3-7(T) showed the highest level of sequence similarity with Bifidobacterium adolescentis KCTC 3216(T) (98.4 %), followed by Bifidobacterium ruminantium KCTC 3425(T) (97.9 %). Analysis of hsp60 sequences showed that strain CU3-7(T) was closely related to B. adolescentis KCTC 3216(T) (94.0 %) and B. ruminantium KCTC 3425(T) (92.5 %). The DNA-DNA hybridization values with the closely related strains were all below the cut-off value for species delineation, 17.0 % with B. ruminantium KCTC 3425(T) and 14.9 % with B. adolescentis KCTC 3216(T). Fructose-6-phosphate phosphoketolase activity was detected. The predominant cellular fatty acids were C16 : 0 (27.7 %), C18 : 1ω9c (27.4 %) and C18 : 1ω9c dimethylacetate (15.5 %). The DNA G+C content was 58.6 mol%. On the basis of polyphasic taxonomy, strain CU3-7(T) should be classified as the type strain of a novel species within the genus Bifidobacterium, for which the name Bifidobacterium faecale sp. nov. is proposed ( = KACC 17904(T) = JCM 19861(T)).

LOWER BIFIDOBACTERIA COUNTS IN ADULT PATIENTS WITH CELIAC DISEASE ON A GLUTEN-FREE DIET

ContextThe ingestion of gluten is responsible for the symptoms of Celiac disease, but other environmental factors can also influence. Strains of theBifidobacterium genus have been shown to afford protection against the inflammatory response and mucosal damage caused by gliadin peptides in vitro.ObjectivesThis study was designed to compare the concentration of fecal bifidobacteria and pH of patients with celiac disease on gluten-free diet and control subjects in order to identify if the imbalance on fecal microbiota still remain during the treatment of celiac disease and identify the necessity of dietary supplementation with pre- or probiotics.MethodsIt was analyzed the feces of 42 healthy subjects and 14 celiac patients. The bifidobacteria count in feces was done in selective medium BIM-25. Microscopic analysis of the colonies was performed by Gram stain. The identification of the genus Bifidobacterium was performed by determination of fructose-6-phosphate phosphoketolase. Fecal pH was measured using a pH meter.ResultsThe concentration of bifidobacteria per gram of feces was significantly higher in healthy subjects (controls) (1.5 ± 0.63 x108 CFU/g) when compared to celiac patients (2.5 ± 1.5 x107 CFU/g). The fecal pH was not different between celiac patients (7.19 ± 0.521) and controls (7.18 ± 0.522).ConclusionsThese results suggest that with lower levels of bifidobacteria, celiac patients have an imbalance in the intestinal microbiota, regardless of pH, even while on a gluten-free diet. This fact could favor the pathological process of the disorder.

Prevalence and characterization of Clostridium perfringens from the faecal microbiota of elderly Irish subjects

The aim of this study was to investigate the diversity and composition of the intestinal microbiota of elderly subjects using a combination of culture-dependent techniques and 16S rRNA gene amplicon sequencing. The study was performed as part of the ELDERMET project, in which 368 faecal samples were assessed for viable numbers of Bifidobacterium spp., Lactobacillus spp. and Enterobacteriaceae on selective agar. However, the Bifidobacterium selective medium used also supported the growth of Clostridium perfringens, which appeared as distinct colonies and were subsequently characterized phenotypically and genotypically. All the isolates were confirmed as toxin biotype A producers. In addition, three isolates tested also had the genetic determinants for the β2 toxin. Of the 368 faecal samples assessed, C. perfringens was detected in 28 samples (7.6%). Moreover, C. perfringens was observed in samples from subjects in all the residence locations assessed but was most prevalent in subjects from long-stay residential care, with 71.4% of the samples (63.2% of the subjects) being from this residence location, and with a shedding level in excess of 10(6) c.f.u. (g faeces)(-1). Microbiota profiling revealed some significant compositional changes across both the family and genus taxonomic levels between the C. perfringens-positive and -negative datasets. Levels of culturable Bifidobacterium spp. and Lactobacillus spp. were significantly (P<0.05) lower in the C. perfringens-positive samples. Sequence-based methods also confirmed a significant difference in the Bifidobacterium spp. level (P<0.05) between both datasets. Taken together, these data suggest that a high viable count [>10(6) c.f.u. (g faeces)(-1)] of C. perfringens in stool samples may be indicative of a less healthy microbiota in the intestine of elderly people in long-stay residential care.

Caenorhabditis elegans as an alternative model host for legionella pneumophila, and protective effects of Bifidobacterium infantis

The survival times of Caenorhabditis elegans worms infected with Legionella pneumophila from day 7.5 or later after hatching were shorter than those of uninfected worms. However, nematodes fed bifidobacteria prior to Legionella infection were resistant to Legionella. These nematodes may act as a unique alternative host for Legionella research.

New selective medium for selection of bifidobacteria from human feces

This work reports an alternative selective medium for reliable and efficient isolation of human fecal bifidobacteria. It uses a base commercially available, does not need pH adjustment and can be autoclaved with its additives. It provides a useful alternative for fecal bifidobacteria isolation.

Quantitative analysis of the intestinal bacterial community in one- to three-week-old commercially reared broiler chickens fed conventional or antibiotic-free vegetable-based diets

AIMS

To explore the effect of drug-free poultry production on the intestinal microflora of broiler chickens, the bacterial community of this environment was quantitatively profiled in both conventionally reared birds and birds reared without antibiotic growth promotants (AGPs) on a vegetable-based diet.

METHODS AND RESULTS

Quantitative, real-time PCR with group-specific 16S rDNA primer sets was used to enumerate the abundance of the following chicken gastrointestinal (GI) tract phylogenetic groups: the Clostridium leptum-Faecalibacterium prausnitzii subgroup (Clostridium genus cluster IV), the Clostridium coccoides - Eubacterium rectale subgroup (Clostridium cluster XIVa and XIVb), the Bacteroides group (including Prevotella and Porphyromonas), Bifidobacterium spp., the Enterobacteriaceae, the Lactobacillus group (including the genera Leuconostoc, Pediococcus, Aerococcus and Weissella), the Clostridium perfringens subgroup (Clostridium cluster I), Enterococcus spp., Veillonella spp., Atopobium spp., Campylobacter spp. and the domain Bacteria. A species-specific 5'-nuclease (Taqman) assay was also employed to specifically assess Cl. perfringens abundance. Ten birds were sampled from each of two commercial chicken houses, one in which feed was supplemented with AGPs and exogenous animal protein, and the other vegetable-based and drug-free, at 7, 14 and 21 days of age. The ileal community was dominated by two large populations, the lactobacilli and the Enterobacteriaceae, with those taxa much more numerous in drug-free vegetable-based diet fed birds than those conventionally reared at the 7- and 14-day time periods. The progressive changes in microflora in both the conventional and drug-free caeca were similar to each other, with the Enterobacteriaceae sequences dominating at day 7, but being replaced by obligate anaerobe signature sequences by day 14. Of note was the finding that all the day 14 and day 21 replicate caecal samples from the drug-free house were positive for Campylobacter spp. averaging >10(8) 16S rDNA gene copies per gram wet weight.

CONCLUSIONS

Quantitative, real-time PCR indicates that the effects of drug-free rearing on the chicken GI tract microbial community are most pronounced in the ileal region, but AGPs may be important in controlling Campylobacter colonization of the caecum.

SIGNIFICANCE AND IMPACT OF THE STUDY

A quantitative taxonomic understanding of the shifting microbial ecology of the broiler chicken gut microbiota is important in the light of AGP withdrawal. AGP withdrawal has occurred in response to concerns over the transfer of antimicrobial-resistant bacteria to humans via the food production chain.

Antibiotic resistance in non-enterococcal lactic acid bacteria and bifidobacteria

Over the last 50 years, human life expectancy and quality of life have increased dramatically due to improvements in nutrition and the use of antibiotics in the fight against infectious diseases. However, the heyday of antibiotic treatment is on the wane due to the appearance and spread of resistance among harmful microorganisms. At present, there is great concern that commensal bacterial populations from food and the gastrointestinal tract (GIT) of humans and animals, such as lactic acid bacteria (LAB) and bifidobacteria, could act as a reservoir for antibiotic resistance genes. Resistances could ultimately be transferred to human pathogenic and opportunistic bacteria hampering the treatment of infections. LAB species have traditionally been used as starter cultures in the production of fermented feed and foodstuffs. Further, LAB and bifidobacteria are normal inhabitants of the GIT where they are known to exert health-promoting effects, and selected strains are currently been used as probiotics. Antibiotic resistance genes carried by LAB and bifidobacteria can be transferred to human pathogenic bacteria either during food manufacture or during passage through the GIT. The aim of this review is to address well-stated and recent knowledge on antibiotic resistance in typical LAB and bifidobacteria species. Therefore, the commonest antibiotic resistance profiles, the distinction between intrinsic and atypical resistances, and some of the genetic determinants already discovered will all be discussed.