Enhanced stress resistance of Bifidobacterium breve NRBB57 by induction of stress proteins at near-zero growth rates.

Bifidobacterium breve is a common habitant of the human gut and is used as probiotic in functional foods. B. breve has to cope with multiple stress conditions encountered during processing and passage through the human gut, including high temperature, low pH and exposure to oxygen. Additionally, during industrial processing and in the gut, B. breve could encounter nutrient limitation resulting in reduced growth rates that can trigger adaptive stress responses. For this reason, it is important to develop culture methods that elicit resistance to multiple stresses (robustness) encountered by the bacteria. To investigate the impact of caloric restriction on robustness of the probiotic B. breve NRBB57, this strain was grown in lactose-limited chemostat cultures and in retentostat for 21 days, at growth rates ranging from 0.4 h-1 to 0.00081 h-1. Proteomes of cells harvested at different growth rates were correlated to acid, hydrogen peroxide and heat stress survival capacity. Comparative proteome analysis showed that retentostat-grown cells had significantly increased abundance of a variety of stress proteins involved in protein quality maintenance and DNA repair (DnaJ, Hsp90, FtsH, ClpB, ClpP1, ClpC, GroES, RuvB, RecA), as well as proteins involved in oxidative stress defence (peroxiredoxin, ferredoxin, thioredoxin peroxidase, glutaredoxin and thioredoxin reductase). Exposure to three different stress conditions, 45 °C, pH 3, and 10 mM H2O2, showed highest stress resistance of retentostat cells sampled at week 2 and week 3 grown at 0.0018 and 0.00081 h-1. Our findings show that cultivation at near-zero growth rates induces higher abundance of stress defence proteins contributing to the robustness of B. breve NRBB57, thereby offering an approach that may support its production and functionality.

[Ditrovie scale: Translation and validation in standard Arabic]. / Échelle Ditrovie : traduction et validation en langue arabe standard.

OBJECTIVES: Our work aimed to translate Ditrovie scale into standard Arabic and to verify its validity and reliability in the Tunisian population. MATERIALS: The translation-retro-translation method was the chosen translation method. The committee of experts analyzed these versions and elaborated a pre-final version The Arabic version obtained was conducted on a sample of 100 patients with idiopathic overactive bladder. The reliability of the scale was verified by Cronbach's alpha coefficient and intraclass correlation coefficient. RESULTS: The feasibility and acceptability of the scale was good. The Cronbach's alpha was 0.86. The reproducibility of our scale as well as of each domain were very good (intraclass correlation coefficient>0.9) with a mean of the differences centered and homogeneous in the Bland and Altman graph. CONCLUSION: The standard Arabic version of the Ditrovie scale is a reliable instrument with satisfactory psychometric properties allowing evaluation of quality of life of patients with idiopathic overactive bladder. LEVEL OF EVIDENCE: B.

Infant formula containing galacto-and fructo-oligosaccharides and Bifidobacterium breve M-16V supports adequate growth and tolerance in healthy infants in a randomised, controlled, double-blind, prospective, multicentre study.

The objective of the present study was to evaluate the growth and tolerance in healthy, term infants consuming a synbiotic formula with daily weight gain as the primary outcome. In a randomised, controlled, double-blind, multicentre, intervention study infants were assigned to an extensively hydrolysed formula containing a specific combination of Bifidobacterium breve M-16V and a prebiotic mixture (short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides in a 9:1 ratio; scGOS/lcFOS; synbiotic group), or the same formula without this synbiotic concept for 13 weeks (control group). Anthropometry, formula intake, tolerance, stool characteristics, blood parameters, faecal microbiota and metabolic faecal profile were assessed. Medically confirmed adverse events were recorded throughout the study. Equivalence in daily weight gain was demonstrated for the intention-to-treat (ITT) population (n 211). In the per-protocol (PP) population (n 102), the 90 % CI of the difference in daily weight gain slightly crossed the lower equivalence margin. During the intervention period, the mean weight-for-age and length-for-age values were close to the median of the WHO growth standards in both groups, indicating adequate growth. The number of adverse events was not different between both groups. No relevant differences were observed in blood parameters indicative for liver and renal function. At 13 weeks, an increased percentage of faecal bifidobacteria (60 v. 48 %) and a reduced percentage of Clostridium lituseburense/C. histolyticum (0·2 v. 2·6 %) were observed in the synbiotic group (n 19) compared with the control group (n 27). In conclusion, this study demonstrates that an extensively hydrolysed formula with B. breve M-16V and the prebiotic mixture scGOS/lcFOS (9:1) supports an adequate infant growth.

Multilocus sequence typing of bifidobacterial strains from infant's faeces and human milk: are bifidobacteria being sustainably shared during breastfeeding?

Bifidobacteria are considered to be one of the most important beneficial intestinal bacteria for infants, contributing to the priming of the mucosal immune system. These microbes can also be detected in mother's milk, suggesting a potential role of human milk in the colonisation of infant's gut. However, little is known about the timing of bacteria appearance in human milk, and whether human milk is the first source of inoculation. Here, we investigated whether specific strains are shared sustainably between maternal milk and infant's gut. Faecal samples and human milk were collected from 102 healthy mother-infant pairs (infant's faeces: meconium, 7, 30 days of age; mother's milk: once before delivery, colostrum, 7, 30 days after delivery). Bifidobacterial strains were isolated from these samples, and were discriminated by means of multilocus sequencing typing. No bifidobacteria were detected from human milk collected before delivery, or colostrum. Strains were isolated only from human milk samples obtained 7 days after birth or later. On the other hand, bifidobacterial strains were obtained from infant's faeces throughout the study period, sometimes as early as the first day of life (meconium). We have found that bifidobacterial species belonging to Bifidobacterium bifidum, Bifidobacterium breve, and Bifidobacterium longum subsp. longum could be identified as monophyletic between infant's faeces and their mother's milk. These strains were confirmed to be sustainably shared between maternal milk and infant's gut. Moreover, monophyletic strains were isolated at the same time point or earlier from infant's faeces than from human milk, and none were isolated earlier from human milk than from infant's faeces. Although it remains unclear whether human milk is the first source of microbes for infants, our results confirm that human milk is a reservoir of bifidobacteria, and specific strains are shared between infant's intestine and human milk during breastfeeding.

Synbiotics prevent asthma-like symptoms in infants with atopic dermatitis.

BACKGROUND: Infants with atopic dermatitis (AD) have a high risk of developing asthma. We investigated the effect of early intervention with synbiotics, a combination of probiotics and prebiotics, on the prevalence of asthma-like symptoms in infants with AD. METHODS: In a double-blind, placebo-controlled multicentre trial, ninety infants with AD, age <7\ months, were randomized to receive an extensively hydrolyzed formula with Bifidobacterium breve M-16V and a galacto/fructooligosaccharide mixture (Immunofortis(®) ), or the same formula without synbiotics during 12 weeks. After 1 year, the prevalence of respiratory symptoms and asthma medication use was evaluated, using a validated questionnaire. Also, total serum IgE and specific IgE against aeroallergens were determined. FINDINGS: Seventy-five children (70.7% male, mean age 17.3 months) completed the 1-year follow-up evaluation. The prevalence of 'frequent wheezing' and 'wheezing and/or noisy breathing apart from colds' was significantly lower in the synbiotic than in the placebo group (13.9%vs 34.2%, absolute risk reduction (ARR) -20.3%, 95% CI -39.2% to -1.5%, and 2.8%vs 30.8%, ARR -28.0%, 95% CI -43.3% to -12.5%, respectively). Significantly less children in the synbiotic than in the placebo group had started to use asthma medication after baseline (5.6%vs 25.6%, ARR -20.1%, 95% CI -35.7% to -4.5%). Total IgE levels did not differ between the two groups. No children in the synbiotic and five children (15.2%) in the placebo group developed elevated IgE levels against cat (ARR -15.2%, 95% CI -27.4% to -2.9%). CONCLUSION: These results suggest that this synbiotic mixture prevents asthma-like symptoms in infants with AD.

Effect of a new synbiotic mixture on atopic dermatitis in infants: a randomized-controlled trial.

BACKGROUND: Clinical trials investigating the therapeutic effect of probiotics on atopic dermatitis (AD) show inconsistent results. Better results can possibly be achieved by combining probiotics with prebiotics, i.e. synbiotics. OBJECTIVE: To investigate the therapeutic effect of a synbiotic mixture on the severity of AD in infants. METHODS: In a double-blind, placebo-controlled multi-centre trial, 90 infants with AD [SCORing Atopic Dermatitis (SCORAD) score > or =15], aged < 7 months and exclusively formula fed, were randomly assigned to receive either an extensively hydrolysed formula with Bifidobacterium breve M-16V and a galacto-/fructooligosaccharide mixture (Immunofortis), or the same formula without synbiotics for 12 weeks. The primary outcome was severity of AD, assessed using the SCORAD index. A secondary outcome measure was intestinal microbiota composition. RESULTS: There was no difference in SCORAD score improvement between the synbiotic and the placebo group. The synbiotic group did have a significantly higher percentage of bifidobacteria (54.7% vs. 30.1%, P<0.001) and significantly lower percentages of Clostridium lituseburense/Clostridium histolyticum (0.5 vs. 1.8, P=0.02) and Eubacterium rectale/Clostridium coccoides (7.5 vs. 38.1, P<0.001) after intervention than the placebo group. In the subgroup of infants with IgE-associated AD (n=48), SCORAD score improvement was significantly greater in the synbiotic than in the placebo group at week 12 (-18.1 vs. -13.5 points, P=0.04). CONCLUSIONS: This synbiotic mixture does not have a beneficial effect on AD severity in infants, although it does successfully modulate their intestinal microbiota. Further randomized-controlled trials should explore a possible beneficial effect in IgE-associated AD.

Early life: gut microbiota and immune development in infancy.

The immune system of infants is actively downregulated during pregnancy and therefore the first months of life represent a period of heightened susceptibility to infection. After birth, there is an age-dependent maturation of the immune system. Exposure to environmental microbial components is suggested to play an important role in the maturation process. The gastrointestinal tract is the major site of interaction between the host immune system and microorganisms, both commensal as well as potentially pathogenic. It is well established that the mammalian immune system is designed to help protect the host from invading microorganisms and other danger signals. However, recent research is emerging in the field of host-microbe interactions showing that commensal microorganisms (microbiota) are most likely one of the drivers of immune development and, in turn the immune system shapes the composition of the microbiota. Specific early microbial exposure of the gut is thought to dramatically reduce the incidence of inflammatory, autoimmune and atopic diseases further fuelling the scientific view that microbial colonisation plays an important role in regulating and fine-tuning the immune system throughout life. Therefore, the use of pre-, pro- and synbiotics may result in a beneficial microbiota composition that might have a pivotal role on the prevention of several important diseases that develop in early life such as necrotizing enterocolitis and atopic eczema.

DNA isolation protocols affect the detection limit of PCR approaches of bacteria in samples from the human gastrointestinal tract.

A major concern in molecular ecological studies is the lysis efficiency of different bacteria in a complex ecosystem. We used a PCR-based 16S rDNA approach to determine the effect of two DNA isolation protocols (i.e. the bead beating and Triton-X100 method) on the detection limit of seven feces-associated bacterial species of different genera. Glycogen was used in these protocols to improve the precipitation of small concentrations of DNA in ethanol without affecting the sequential procedures. The PCR detection limit of 16S rDNA amplicons on agarose gel from the seven strains tested varied between 8.0 (+/- 1.3) x 10(4) and 4.3 (+/- 1.6) x 10(6) cells for the bead beating method, and between 8.0 (+/- 1.3) x 10(4) and 5.4 (+/- 0.7) x 10(8) cells for the Triton X-100 method. These large differences are most like due to the difference in cell lysis efficiency, since a competitive PCR experiment did not indicate any preference for gram negative, low G+C gram positive or high G+C gram positive bacteria. Denaturing gradient gel electrophoresis (DGGE) analysis was performed to investigate the effect of both DNA isolation protocols on the lysis efficiency of bacteria in fecal samples. A higher diversity in fecal samples was observed with the bead beating method than with the Triton-X100 method. Bands in the bead beating method-derived DGGE profiles corresponding to bands of cloned sequences of the Clostridium coccoides-Eubacterium rectale group and uncultured Fusobacterium prausnitzii were absent or had low intensity in the Triton X-100 method-derived profiles. The applicability of the bead beating method was further investigated by analyzing biopsy samples from the human colon which contain approximately 10(6) cells.