The use of Probiotics to Prevent Diarrhea in Young Children Attending Child Care Centers: A Review

Effect of probiotics on thymus size and markers of infection in late infancy: a randomized controlled trial

BACKGROUND

Probiotics are known to stimulate the immune system but the effect on thymus size in late infancy is unknown. We examined the effect of probiotics on thymus size and C-reactive protein (CRP) in healthy Danish infants starting daycare. We further examined associations between thymus size, CRP and recent infections.

METHODS

The study included 186 children randomized to a combination of Lactobacillus rhamnosus, LGG® and Bifidobacterium animalis spp. lactis, BB-12® or placebo for 6 months. Thymus size, assessed as thymus index (TI) and thymus weight index (TWI), was measured by ultrasound at baseline and at endpoint. Blood samples were drawn to measure CRP. Infections were parent-reported.

RESULTS

There was no significant difference in thymus size between the probiotic group and placebo (p ≥ 0.248) but TWI tended to be higher in the probiotic group corresponding to 5% higher than placebo (p = 0.068) in an adjusted model. There was no effect of probiotics on CRP (p = 0.331). At the endpoint, thymus size was inversely associated with CRP (p ≤ 0.040), diarrhea (p ≤ 0.050), and TI was also associated with the absence from daycare due to respiratory or gastrointestinal infections (p = 0.010).

CONCLUSION

The probiotic intervention had no effect on thymus size or CRP in Danish children at the age of starting daycare.

IMPACT

Overall there was no effect on thymus size of a combination of Lactobacillus rhamnosus, LGG® and Bifidobacterium animalis spp. lactis, BB-12® administered to Danish children starting daycare. This study examines the effect of probiotics on thymus size in healthy children when they start daycare thus exposed for infections while their immune system is still developing. This has to our knowledge not been described before. We found no significant difference in thymus size between the probiotic and placebo groups, but for thymus weight index, there was a trend. This should be investigated further in studies designed for this as primary outcome.

The Role of Probiotics in the Prevention and Treatment of Atopic Dermatitis in Children: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease common among infants and children. It is associated with a high risk of allergies, asthma, and mental health problems. Attempts have been made to use probiotics in clinical interventions for AD.

OBJECTIVE

Our objective was to perform an updated meta-analysis of recently published studies to evaluate the effect of probiotics in the prevention and treatment of AD in children and to further understand the role of probiotics in AD interventions in the clinic.

METHOD

We searched the PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and Wanfang databases with prespecified selection criteria from inception of each database to 11 January 2020. No language restrictions were applied.

RESULTS

A total of 25 studies were included in our meta-analysis. Of these, 14 were prevention studies (with 3049 children enrolled) and 11 were treatment studies (with 816 children enrolled). One treatment study was excluded after the sensitivity analysis. From the 14 prevention studies included, the pooled relative risk ratio of AD in those treated with probiotics versus placebo was 0.70 [95% confidence interval (CI) 0.57-0.84; P = 0.0002]. Subgroup analyses showed that only mixed strains of probiotics had a significant effect on lowering the incidence of AD. Probiotics administered solely to infants did not prevent the development of AD, but effects were significant when probiotics were administered to both pregnant mothers and their infants or solely to pregnant mothers. In studies with treatment durations > 6 months, the incidence of AD decreased significantly; a similar effect was achieved when the treatment duration was < 6 months. Meta-analysis of the ten treatment studies showed a significant decrease in the weighted mean difference (WMD) in Scoring Atopic Dermatitis (SCORAD) index values in the probiotics group compared with the control group (WMD, - 7.23; 95% CI - 10.59 to - 3.88; P < 0.0001). Subgroup analyses showed that both single-strain and mixed-strain probiotics had a significant effect on improving SCORAD values. Studies with participants aged < 1 year (P = 0.07) reported no significant results. In studies with treatment periods > 8 weeks, SCORAD values seemed to decrease more than in studies with treatment periods < 8 weeks. However, the subgroup difference was only statistically significant when the analysis was performed according to participant age in prevention studies.

CONCLUSION

Our updated meta-analysis demonstrates that interventions with probiotics potentially lower the incidence of AD and relieve AD symptoms in children, particularly when treating infants and children aged ≥ 1 year with AD. Interventions with mixed-strain probiotics tended to have better preventive and curative effects. Probiotics administered solely to infants appeared to produce negative preventive effects. Different intervention durations might also affect clinical outcomes. However, given the insignificant subgroup differences, except for treatment by participant age, and the moderate heterogeneity among the studies, these conclusions should be interpreted with caution, and more powerful randomized controlled trials using standardized measurements should be conducted to assess the long-term effects of probiotics.

Intestinal Microbiota in Early Life and Its Implications on Childhood Health

Trillions of microbes reside in the human body and participate in multiple physiological and pathophysiological processes that affect host health throughout the life cycle. The microbiome is hallmarked by distinctive compositional and functional features across different life periods. Accumulating evidence has shown that microbes residing in the human body may play fundamental roles in infant development and the maturation of the immune system. Gut microbes are thought to be essential for the facilitation of infantile and childhood development and immunity by assisting in breaking down food substances to liberate nutrients, protecting against pathogens, stimulating or modulating the immune system, and exerting control over the hypothalamic-pituitary-adrenal axis. This review aims to summarize the current understanding of the colonization and development of the gut microbiota in early life, highlighting the recent findings regarding the role of intestinal microbes in pediatric diseases. Furthermore, we also discuss the microbiota-mediated therapeutics that can reconfigure bacterial communities to treat dysbiosis.

Immune-Mediated Mechanisms of Action of Probiotics and Synbiotics in Treating Pediatric Intestinal Diseases

The pediatric population is continually at risk of developing infectious and inflammatory diseases. The treatment for infections, particularly gastrointestinal conditions, focuses on oral or intravenous rehydration, nutritional support and, in certain case, antibiotics. Over the past decade, the probiotics and synbiotics administration for the prevention and treatment of different acute and chronic infectious diseases has dramatically increased. Probiotic microorganisms are primarily used as treatments because they can stimulate changes in the intestinal microbial ecosystem and improve the immunological status of the host. The beneficial impact of probiotics is mediated by different mechanisms. These mechanisms include the probiotics' capacity to increase the intestinal barrier function, to prevent bacterial transferation and to modulate inflammation through immune receptor cascade signaling, as well as their ability to regulate the expression of selected host intestinal genes. Nevertheless, with respect to pediatric intestinal diseases, information pertaining to these key mechanisms of action is scarce, particularly for immune-mediated mechanisms of action. In the present work, we review the biochemical and molecular mechanisms of action of probiotics and synbiotics that affect the immune system.

Probiotics and Child Care Absence Due to Infections: A Randomized Controlled Trial

OBJECTIVES

The risk of infections is higher in children attending child care compared with children cared for at home. This study examined the effect of a combination of probiotics on absence from child care because of respiratory and gastrointestinal infections in healthy infants aged 8 to 14 months at the time of enrollment in child care.

METHODS

The ProbiComp study was a randomized, double-blind, placebo-controlled study. A total of 290 infants were randomly allocated to receive a placebo or a combination of Bifidobacterium animalis subsp lactis and Lactobacillus rhamnosus in a dose of 10⁹ colony-forming units of each daily for a 6-month intervention period. Absence from child care, occurrence of infant symptoms of illness, and doctor visits were registered by the parents using daily and weekly Web-based questionnaires.

RESULTS

Median absence from child care was 11 days (interquartile range: 6-16). Intention-to-treat analysis showed no difference between the probiotics and placebo groups (P = .19). Additionally, there was no difference in any of the secondary outcomes between groups; the number of children with doctor-diagnosed upper or lower respiratory tract infections, the number of doctor visits, antibiotic treatments, occurrence and duration of diarrhea, and days with common cold symptoms, fever, vomiting, or caregivers' absence from work.

CONCLUSIONS

A daily administration of a combination of B animalis subsp lactis and L rhamnosus for 6 months did not reduce the number of days absent from child care in healthy infants at the time of enrollment in child care.

In vitro antiviral activity of Lactobacillus casei and Bifidobacterium adolescentis against rotavirus infection monitored by NSP4 protein production

AIMS

The aim of this study was to determine the antiviral activity of four probiotic metabolites (Lactobacillus and Bifidobacetrium species) against rotavirus in vitro infection monitored by the NSP4 protein production and Ca(2+) release.

METHODS AND RESULTS

The antiviral effect of the metabolites was performed due a comparison between a blocking model and an intracelullar model on MA104 cells, with the response of NSP4 production and Ca(2+) liberation measured by flow cytometry. Significant results were obtained with the metabolites of Lactobacillus casei, and Bifidobacterium adolescentis in the reduction of the protein production (P = 0·04 and P = 0·014) and Ca(2+) liberation (P = 0·094 and P = 0·020) in the intracellular model, which suggests a successful antiviral activity against RV infection.

CONCLUSIONS

This study demonstrates that probiotic metabolites were able to interfere with the final amount of intracellular NSP4 protein and a successful Ca(2+) regulation, which suggests a new approach to the mechanism exerted by probiotics against the rotavirus infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

A novel anti-rotaviral effect exerted by probiotic metabolites monitored by the NSP4 protein during the RV in vitro infection and the effect on the Ca(2+) release is reported; suggesting a reduction on the impact of the infection by decreasing the damage of the cells preventing the electrolyte loss.

Bioactivity characterization of Lactobacillus strains isolated from dairy products

This study aimed to find candidate strains of Lactobacillus isolated from sheep dairy products (yogurt and ewe colostrum) with probiotic and anticancer activity. A total of 100 samples were randomly collected from yogurt and colostrum and 125 lactic acid bacteria were isolated. Of these, 17 Lactobacillus strains belonging to five species (L. delbrueckii, L. plantarum, L. rhamnosus, L. paracasei, and L. casei) were identified. L. plantarum 17C and 13C, which isolated from colostrums, demonstrated remarkable results such as resistant to low pH and high concentrations of bile salts, susceptible to some antibiotics and good antimicrobial activity that candidate them as potential probiotics. Seven strains (1C, 5C, 12C, 13C, 17C, 7M, and 40M), the most resistant to simulated digestion, were further investigated to evaluate their capability to adhere to human intestinal Caco-2 cells. L. plantarum 17C was the most adherent strain. The bioactivity assessment of L. plantarum 17C showed anticancer effects via the induction of apoptosis on HT-29 human cancer cells and negligible side effects on one human epithelial normal cell line (FHs 74). The metabolites produced by this strain can be used as alternative pharmaceutical compounds with promising therapeutic indices because they are not cytotoxic to normal mammalian cells.

Probiotic assessment of Enterococcus durans 6HL and Lactococcus lactis 2HL isolated from vaginal microflora

Forty-five lactic acid bacteria (LAB) were isolated from the vaginal specimens of healthy fertile women, and the identities of the bacteria were confirmed by sequencing of their 16S rDNA genes. Among these bacteria, only four isolates were able to resist and survive in low pH, bile salts and simulated in vitro digestion conditions. Lactococcus lactis 2HL, Enterococcus durans 6HL, Lactobacillus acidophilus 36YL and Lactobacillus plantarum 5BL showed the best resistance to these conditions. These strains were evaluated further to assess their ability to adhere to human intestinal Caco-2 cells. Lactococcus lactis 2HL and E. durans 6HL were the most adherent strains. In vitro tests under neutralized pH proved the antimicrobial activity of both strains. Results revealed that the growth of Escherichia coli O26, Staphylococcus aureus and Shigella flexneri was suppressed by both LAB strains. The antibiotic susceptibility tests showed that these strains were sensitive to all nine antibiotics: vancomycin, tetracycline, ampicillin, penicillin, gentamicin, erythromycin, clindamycin, sulfamethoxazole and chloramphenicol. These data suggest that E. durans 6HL and Lactococcus lactis 2HL could be examined further for their useful properties and could be developed as new probiotics.

Enumeration of bifidobacteria using Petrifilm™ AC in pure cultures and in a fermented milk manufactured with a commercial culture of Streptococcus thermophilus

Bifidobacteria are probiotic microorganisms that are widely used in the food industry. With the aim of using of Petrifilm™ Aerobic Count (AC) plates associated with selective culture media, aliquots of sterile skim milk were inoculated separately with four commercial cultures of bifidobacteria. These cultures were plated by both the conventional method and Petrifilm™AC, using the culture media NNLP and ABC. The cultures were incubated under anaerobiosis at 37 °C for 24, 48 and 72 h. No significant differences (p > 0.05) were observed between the obtained counts at 48 and 72 h. Bifidobacteria counts in ABC were usually higher than in NNLP, independent of the plating method. Subsequently, fermented milk was prepared with a Streptococcus thermophilus strain, and aliquots were inoculated with the same bifidobacteria. Then, the fermented milks were submitted to microbiological analysis for bifidobacteria enumeration using the same culture media and methodologies previously described, incubated under anaerobiosis at 37 °C for 48 h. Again, bifidobacteria counts in ABC were higher than in NNLP, with significant differences for some cultures (p < 0.05). The counts obtained by both methodologies presented significant correlations (p < 0.05). The results indicate the viability of Petrifilm™AC as an alternative method for bifidobacteria enumeration when associated to specific culture media, specially the ABC.