Use of a fermented dairy probiotic drink containing Lactobacillus casei (DN-114 001) to decrease the rate of illness in kids: the DRINK study. A patient-oriented, double-blind, cluster-randomized, placebo-controlled, clinical trial

Probiotics in Children: What Is the Evidence?

The number of papers discussing probiotics increases tremendously that limits the possibility for primary care physicians and clinicians to stay updated. Therefore, the aim of this paper will be to summarize available evidence of probiotic use in well-defined clinical indications of importance for pediatricians. Based on currently available evidence certain probiotic strains (Lactobacillus rhamnosus GG [LGG] and Saccharomyces boulardii) have proven effect in the treatment of acute gastroenteritis and prevention of antibiotic associated diarrhea. Furthermore, LGG was proven to be effective in prevention of nosocomial diarrhea and respiratory tract infection in day care centers. In conclusion, not all probiotic strains have same efficacy for all clinical indications, therefore, only strains with proven efficacy and safety should be recommended.

Probiotic guidelines and physician practice: a cross-sectional survey and overview of the literature

Probiotic use by patients and physicians has dramatically increased over the last decade, although definitive evidence is often lacking for their use. We examined probiotic-prescribing practices among health care providers (HCP) at a tertiary medical centre and compared these practices to clinical guidelines. HCP at the Stanford Medical Center received a survey on probiotic prescribing practices including choice of probiotic and primary indications. A broad overview of the literature was performed. Among 2,331 HCP surveyed, 632 responded. Of the 582 of these who routinely prescribed medications, 61% had recommended probiotic foods or supplements to their patients. Women and gastroenterologists were more likely to prescribe probiotics (odds ratio (OR): 1.5, 95% confidence interval (CI): 1.0-2.1; OR: 3.9, 95% CI: 1.5-10.1, respectively). Among probiotic prescribers, 50% prescribed inconsistently or upon patient request, and 40% left probiotic choice to the patient. Common indications for probiotics, particularly Lactobacillus GG, were prevention and treatment of antibiotic-associated diarrhoea (79 and 66%, respectively). Probiotics were often prescribed for ‘general bowel health’ or at patient request (27 and 39% of responders, respectively). Most respondents (63%) thought an electronic medical record (EMR) pop-up would change probiotic prescribing patterns. However, a review of published guidelines and large trials found inconsistencies in probiotic indications, dosages and strain selection. Probiotic prescribing is common but lacks consistency, with choice of probiotic frequently left to the patient, even for indications with some strain-specific evidence. Implementation of EMR pop-ups/pocket guides may increase consistency in probiotic prescribing, although the lack of clear and consistent guidelines must first be addressed with large, well-designed clinical trials.

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.

Preventive Effect of Cow's Milk Fermented with Lactobacillus paracasei CBA L74 on Common Infectious Diseases in Children: A Multicenter Randomized Controlled Trial

Background: Fermented foods have been proposed to prevent common infectious diseases (CIDs) in children attending day care or preschool.

OBJECTIVES

To investigate the efficacy of dietary supplementation with cow's skim milk fermented with the probiotic Lactobacillus paracasei CBA L74 in reducing CIDs in children attending day care or preschool. Methods: Multicenter, randomized, double-blind, placebo-controlled trial on healthy children (aged 12-48 months) consuming daily 7 grams of cow's skim milk fermented with L. paracasei CBA L74 (group A), or placebo (maltodextrins group B) attending day care or preschool during the winter season. The main outcome was the proportion of children who experienced ≥1 episode of CID during a 3-month follow-up. Fecal biomarkers of innate (α- and β-defensins, cathelicidin) and acquired immunity (secretory IgA) were also monitored. Results: A total of 126 children (71 males, 56%) with a mean (SD) age of 33 (9) months completed the study, 66 in group A and 60 in group B. At intention to treat analysis, the proportion of children presenting ≥1 CID was 60% in group A vs. 83% in group B, corresponding to an absolute risk difference (ARD) of -23% (95% CI: -37% to -9%, p < 0.01). At per-protocol-analysis (PPA), the proportion of children presenting ≥1 CID was 18% in group A vs. 40% in group B, corresponding to an absolute risk difference (ARD) of -22% (95% CI: -37% to -6%, p < 0.01). PPA showed that the proportion of children presenting ≥1 acute gastroenteritis (AGE) was significantly lower in group A (18% vs. 40%, p < 0.05). The ARD for the occurrence of ≥1 AGE was -22% (95% CI: -37% to -6%, p < 0.01) in group A. Similar findings were obtained at PPA regarding the proportion of children presenting ≥1 upper respiratory tract infection (URTI), which was significantly lower in group A (51% vs. 74%, p < 0.05), corresponding to an ARD of -23% (95% CI: -40% to -7%, p < 0.01). Significant changes in innate and acquired immunity biomarkers were observed only in subjects in group A. Conclusions: Dietary supplementation with cow's skim milk fermented with L. paracasei CBA L74 is an efficient strategy in preventing CIDs in children.

Network meta-analysis of probiotics to prevent respiratory infections in children and adolescents

Probiotics have emerged as a promising intervention for the prevention of respiratory tract infections (RTIs) in children. Assess the effect of probiotics on prevention of RTIs in children and adolescents. MEDLINE, EMBASE, LILACS, SCIELO, CINAHL, SCOPUS, and Web of Science. Key words: "respiratory tract infections" AND probiotics. Randomized controlled trials RCT assessing the effect of probiotics on RTIs in children and adolescents were included. Two reviewers, working independently, to identify studies that met the eligibility criteria. Main and secondary outcomes were RTIs and adverse effects, respectively. Twenty-one trials with 6.603 participants were included. Pairwise meta-analysis suggested that Lactobacillus casei rhamnosus (LCA) was the only effective probiotic to the rate of RTIs compared to placebo (RR0.38; Crl 0.19-0.45). Network analysis showed that the LCA exhibited 54.7% probability of being classified in first, while the probability of Lactobacillus fermentum CECT5716 (LFC) being last in the ranking was 15.3%. LCA showed no better effect compared to other probiotic strains by indirect analysis. This systematic review found a lack of evidence to support the effect of probiotic on the incidence rate of respiratory infections in children and adolescents. Pediatr Pulmonol. 2017;52:833-843. © 2017 Wiley Periodicals, Inc.

Mismatch between Probiotic Benefits in Trials versus Food Products

Probiotic food products contain a variety of different bacterial strains and may offer different health effects. The objective was to document the prevalence and dosage of probiotic strains in the Canadian food supply and to review the literature investigating these strains in order to understand what health benefits these products may offer. The Food Label Information Program was used to identify probiotic-containing products in the food supply. PubMed, Web of Science, and Embase were searched for randomized controlled trials that tested the health effects of these strains in humans. There were six probiotic strains/strain combinations identified in the food supply. Thirty-one studies investigated these strains and found that they are associated with decreased diarrhea and constipation, improved digestive symptoms, glycemic control, antioxidant status, blood lipids, oral health, and infant breastfeeding outcomes, as well as enhanced immunity and support for Helicobacter pylori eradication. There were a limited number of studies investigating these strains. Many studies were funded by the food industry and tested dosages that were up to twenty-five times the dosage found in most food products. Probiotic food products could have health benefits not currently reported on their labels. However, many dosages are too low to provide the benefits demonstrated in clinical trials. Further research is needed to enable more effective use of these functional foods.

Daily intake of fermented milk with Lactobacillus casei strain Shirota reduces the incidence and duration of upper respiratory tract infections in healthy middle-aged office workers

PURPOSE

Although several studies have demonstrated the efficacy of probiotics for preventing upper respiratory tract infections (URTIs) in at-risk populations, including children and the elderly, few studies have investigated the efficacy of probiotics in healthy adults living normal, everyday lives. Thus, we tried to evaluate the effects of Lactobacillus casei strain Shirota-fermented milk (LcS-FM) on the incidence of URTIs in healthy middle-aged office workers.

METHODS

In a randomized controlled trial, 96 eligible male workers aged 30-49 years consumed LcS-FM containing 1.0 × 1011 viable LcS cells or control milk (CM) once daily for 12 weeks during the winter season. URTI episodes were evaluated by a physician via a questionnaire of URTI symptoms.

RESULTS

The incidence of URTIs during the intervention period was significantly lower in the LcS-FM group than in the CM group (22.4 vs. 53.2 %, P = 0.002). The time-to-event analysis showed that the LcS-FM group had a significantly higher URTI-free rate than the CM group over the test period (log-rank test: χ 2 11.25, P = 0.0008). The cumulative number of URTI episodes and cumulative days with URTI symptoms per person was lower in the LcS-FM group, and the duration per episode was shorter. Inhibition of both reductions in NK cell activity in peripheral blood mononuclear cells and increases in salivary cortisol levels was observed in the LcS-FM group.

CONCLUSION

The results suggest that the daily intake of fermented milk with LcS may reduce the risk of URTIs in healthy middle-aged office workers, probably through modulation of the immune system.

Antiviral Probiotics: A New Concept in Medical Sciences

In recent decades, probiotics have shown beneficial effects on animal and human health. Probiotics can protect the host against several health threats, including infectious diseases. Before 1995, researchers believed that the effect of probiotics was only on gut microbiota which can restore the gut flora and thus prevent pathogenic bacteria from triggering gastroenteritis. Recent studies have shown that the immunomodulatory activity is the most important mechanism of action of probiotics. From this information, researchers started to evaluate the effect of some immunobiotics, not only on pathogenic bacteria but also on viruses, including enteric and respiratory viruses. Several studies have confirmed the potential antiviral activity of some probiotics due to the immunomodulatory effect. These studies were conducted on humans (clinical trials) and in animal models. In this chapter, probiotics with antiviral effect against respiratory and enteric viruses will be presented and discussed, as well as their mechanisms of action.

Fermented Milk Consumption and Common Infections in Children Attending Day-Care Centers: A Randomized Trial

OBJECTIVES

This multicenter, double-blind, randomized, placebo-controlled clinical trial investigated the effect of a fermented milk product containing the Lactobacillus casei National Collection of Microorganisms and Cell Cultures (CNCM) I-1518 strain on respiratory and gastrointestinal common infectious diseases (CIDs) in children attending day-care centers in Russia.

METHODS

Children ages 3 to 6 years received 100 g of a fermented milk product (n = 300) or a control product (n = 299) twice daily for 3 months, followed by a 1-month observation period. The primary outcome was the incidence of CIDs during the product consumption period.

RESULTS

There was no significant difference in the incidence of CIDs between the groups (N = 98 with fermented milk product vs N = 93 with control product). The overall number of CIDs (and no severe cases at all) in both study groups and in all 12 centers, however, was unexpectedly low resulting in underpowering of the study. No differences were found between the groups in the duration or severity of disease, duration of sick leave from day-care centers, parental missed working days, or in quality-of-life dimensions on the PedsQL questionnaire (P > 0.05).There was, however, a significantly lower incidence of the most frequently observed CID, rhinopharyngitis, in children consuming the fermented milk product compared with those consuming the control product (N = 81 vs N = 100, relative risk 0.82, 95% confidence interval 0.69-0.96, P = 0.017) when considering the entire study period.

CONCLUSIONS

Although no other significant differences were shown between the fermented milk and control product groups in this study, lower incidence of rhinopharyngitis may indicate a beneficial effect of this fermented milk product.

Bugs and Guts: Practical Applications of Probiotics for Gastrointestinal Disorders in Children

Probiotics are foods or products that contain live microorganisms that benefit the host when administered. In this clinical review, we evaluate the literature associated with using probiotics in common pediatric gastrointestinal disorders, focusing specifically on antibiotic-associated diarrhea, acute gastroenteritis, Clostridium difficile infection (CDI), colic, inflammatory bowel disease, and functional gastrointestinal diseases. Meta-analysis of several randomized controlled trials have confirmed benefit for the administration of Lactobacillus rhamnosus GG and Saccharomyces boulardii to prevent antibiotic-associated diarrhea and to treat acute infectious diarrhea. Individual studies have also suggested benefit of probiotics to prevent acute gastroenteritis and serve as an adjunct in ulcerative colitis, pouchitis, antibiotic-associated diarrhea, CDI, functional abdominal pain, irritable bowel syndrome, and colic in breastfed babies. Although promising, larger well-designed studies need to confirm these findings. There is currently insufficient evidence to recommend probiotics for the treatment of constipation-predominant irritable bowel syndrome or Crohn's disease.

Probiotics for prevention and treatment of respiratory tract infections in children: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Respiratory tract infections (RTIs) represent one of the main health problems in children. Probiotics are viable bacteria that colonize the intestine and affect the host intestinal microbial balance. Accumulating evidence suggests that probiotic consumption may decrease the incidence of or modify RTIs. The authors systematically reviewed data from randomized controlled trials (RCTs) to investigate the effect of probiotic consumption on RTIs in children.

METHODS

MEDLINE/PubMed, Embase, Cochrane Library, and Web of Science were systematically searched for RCTs regarding the effect of probiotics on RTIs in children. The outcomes included number of children experienced with at least 1 RTI episode, duration of illness episodes, days of illness per subject, and school/day care absenteeism due to infection. A random-effects model was used to calculate pooled relative risks, or mean difference (MD) with the corresponding 95% confidence interval (CI).

RESULTS

A total of 23 trials involving 6269 children were eligible for inclusion in the systematic review. None of the trials showed a high risk of bias. The quality of the evidence of outcomes was moderate. The age range of subjects was from newborn to 18 years. The results of meta-analysis showed that probiotic consumption significantly decreased the number of subjects having at least 1 RTI episode (17 RCTs, 4513 children, relative risk 0.89, 95% CI 0.82-0.96, P = 0.004). Children supplemented with probiotics had fewer numbers of days of RTIs per person compared with children who had taken a placebo (6 RCTs, 2067 children, MD -0.16, 95% CI -0.29 to 0.02, P = 0.03), and had fewer numbers of days absent from day care/school (8 RCTs, 1499 children, MD -0.94, 95% CI -1.72 to -0.15, P = 0.02). However, there was no statistically significant difference of illness episode duration between probiotic intervention group and placebo group (9 RCTs, 2817 children, MD -0.60, 95% CI -1.49 to 0.30, P = 0.19).

CONCLUSION

Based on the available data and taking into account the safety profile of RCTs, probiotic consumption appears to be a feasible way to decrease the incidence of RTIs in children.

Anti-infective activities of lactobacillus strains in the human intestinal microbiota: from probiotics to gastrointestinal anti-infectious biotherapeutic agents

A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules. The human intestinal microbiota is a source from which Lactobacillus probiotic strains have often been isolated. Only six probiotic Lactobacillus strains isolated from human intestinal microbiota, i.e., L. rhamnosus GG, L. casei Shirota YIT9029, L. casei DN-114 001, L. johnsonii NCC 533, L. acidophilus LB, and L. reuteri DSM 17938, have been well characterized with regard to their potential antimicrobial effects against the major gastric and enteric bacterial pathogens and rotavirus. In this review, we describe the current knowledge concerning the experimental antibacterial activities, including antibiotic-like and cell-regulating activities, and therapeutic effects demonstrated in well-conducted, placebo-controlled, randomized clinical trials of these probiotic Lactobacillus strains. What is known about the antimicrobial activities supported by the molecules secreted by such probiotic Lactobacillus strains suggests that they constitute a promising new source for the development of innovative anti-infectious agents that act luminally and intracellularly in the gastrointestinal tract.

The role of probiotics and prebiotics in the prevention of infections in child day-care centres

Infants and children attending day-care centres demonstrate a notably higher risk of gastrointestinal as well as of respiratory tract infections. The present short review evaluates various well-controlled clinical trials analysing the effect of probiotics and prebiotics in the prevention of such infections. In most of the 12 studies identified, probiotic supplementation was found to be a safe and effective therapeutic tool in preventing gastrointestinal and respiratory infection in this population.

Cow's milk and rice fermented with Lactobacillus paracasei CBA L74 prevent infectious diseases in children: A randomized controlled trial

BACKGROUND & AIM

Fermented foods have been proposed for the prevention of infectious diseases. We evaluated the efficacy of fermented foods in reducing common infectious diseases (CIDs) in children attending daycare.

METHODS

Prospective randomized, double-blind, placebo-controlled trial (registered under Clinical Trials.gov identifier NCT01909128) on healthy children (aged 12-48 months) consuming daily cow's milk (group A) or rice (group B) fermented with Lactobacillus paracasei CBA L74, or placebo (group C) for three months during the winter season. The main study outcome was the proportion of children who experienced at least one CID. All CIDs were diagnosed by family pediatricians. Fecal concentrations of innate (α- and β-defensins and cathelicidin LL-37) and acquired immunity biomarkers (secretory IgA) were also evaluated.

RESULTS

377 children (193 males, 51%) with a mean (SD) age of 32 (10) months completed the study: 137 in group A, 118 in group B and 122 in group C. Intention-to-treat analysis showed that the proportion of children who experienced at least one CID was lower in group A (51.8%) and B (65.9%) compared to group C (80.3%). Per-protocol analysis showed that the proportion of children presenting upper respiratory tract infections was lower in group A (48.2%) and group B (58.5%) compared with group C (70.5%). The proportion of children presenting acute gastroenteritis was also lower in group A (13.1%) and group B (19.5%) compared with group C (31.1%). A net increase of all fecal biomarkers of innate and acquired immunity was observed for groups A and B compared to group C. Moreover, there was a negative association between fecal biomarkers and the occurrence of CID.

CONCLUSION

Dietary supplementation with cow's milk or rice fermented with L. paracasei CBA L74 prevents CIDs in children attending daycare possibly by means of a stimulation of innate and acquired immunity.

Use of probiotics in pediatric infectious diseases

We summarize current evidence and recommendations for the use of probiotics in childhood infectious diseases. Probiotics may be of benefit in treating acute infectious diarrhea and reducing antibiotic-associated diarrhea. Potential benefits of probiotic on prevention of traveler's diarrhea,Clostridium difficile-associated diarrhea, side effects of triple therapy in Helicobacter pylori eradication, necrotizing enterocolitis, acute diarrhea, acute respiratory infections and recurrent urinary tract infections remain unclear. More studies are needed to investigate optimal strain, dosage, bioavailability of drops and tablets, duration of treatment and safety. Probiotics and recombinant probiotic strain represent a promising source of molecules for the development of novel anti-infectious therapy.

Role of short-term use of L. acidophilus DDS-1 and B. lactis UABLA-12 in acute respiratory infections in children: a randomized controlled trial

BACKGROUND/OBJECTIVES

Evidence suggests that the long-term consumption of probiotics may help in reducing the incidence of or modifying acute respiratory infection (ARI). We assessed the role of the short-term use of probiotics in ARI in children.

SUBJECTS/METHODS

This was a randomized, double-blind, controlled study that enrolled 315 children with 90 dropouts. On the first day of appearance of a sick household member, otherwise healthy children of both sexes aged 3-12 years were allocated to receive Lactobacillus acidophilus DDS-1 and Bifidobacterium lactis UABLA-12 (Up4-Junior) in a dose of 5 billion colony-forming units daily with 50 mg of fructooligosaccharide (the probiotic group) or rice maltodexrin (the control group). Test supplementation and follow-up lasted for 2 weeks or until the end of the secondary ARI in a child. The primary outcome measure was the incidence of ARI. Time to resolution and the severity of ARI served the secondary outcome measures.

RESULTS

In all, 64 of 113 children in the probiotic group (57%) and 73 of 112 children in the control group (65%) developed ARI (P=0.261). Time to resolution of the secondary ARI was shorter in the probiotic group (5.0 (interquartile range (IQR): 4.0-6.0) vs 7.0 (IQR: 6.0-8.0) days, P<0.001). The median severity of ARI was 240 (IQR: 163-350) score-days in the probiotic vs 525 (IQR: 364-736) score-days in the control group (P<0.001).

CONCLUSIONS

The short-term use of probiotics does not reduce the incidence, but shortens ARI in preschool and elementary school children.

Randomized, double-blind, placebo-controlled study of synbiotic yogurt effect on the health of children

OBJECTIVE

To assess the effects of daily consumption of a synbiotic yogurt drink on the health, growth, and quality of life of healthy children 12-48 months of age in out-of-home child care.

STUDY DESIGN

Healthy children attending child care centers were enrolled in a prospective, double-blind, placebo-controlled clinical trial. The intervention was a yogurt drink containing Streptococcus thermophilus, Lactobacillus bulgaricus, and Bifidobacterium animalis subspecies lactis (BB-12) (5 × 10(9) cfu/100 mL serving), and 1 g of inulin (synbiotic group) vs a similar nonsynbiotic-containing acidified milk drink (placebo group) once daily for 16 weeks. The end points were days of diarrhea, fever, vomiting, symptoms of upper respiratory tract infection, use of antibiotics, physician visits, child care absenteeism, parental work absenteeism, and quality of life (PedsQL 4.0; Mapi Research Trust, Lyon, France).

RESULTS

Compared with placebo (n = 73), children receiving synbiotic (n = 76) had significantly fewer days of reported fever (1.85 vs 1.95, P < .05), significant improvement in social functioning (P < .035; pre-to-end intervention), and school functioning (P < .045; pre-to-mid intervention). More days with ≥ 3 loose/watery stools were reported in the synbiotic group (P < .05).

CONCLUSIONS

Daily supplementation of children's diet with yogurt containing probiotic bacteria BB-12 and inulin significantly reduced days of fever and improved social and school functioning. The increased frequency of bowel movements may be explained by an accelerating effect of BB-12 and inulin on intestinal transit. Further research on the possible benefits of synbiotics on children's health is advised.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00653705.

Safety of probiotics and synbiotics in children under 18 years of age

This study aimed to systematically evaluate safety of probiotics and synbiotics in children ageing 0-18 years. This study is the third and final part in a safety trilogy and an update is provided using the most recent available clinical data (2008-2013) by means of the Common Terminology Clinical Adverse Events (CTCAE version 4.0) classification. Safety aspects are represented and related to number of participants per probiotic strain/culture, study duration, dosage, clinical condition and selected afflictions. Analysis of 74 clinical studies indicated that probiotic and/or synbiotic administration in children is safe with regard to the specific evaluated strains, dosages and duration. The population of children include healthy, immune compromised and obese subjects, as well as subjects with intestinal disorders, infections and inflammatory disorders. This study revealed no major safety concerns, as the adverse events (AEs) were unrelated, or not suspected to be related, to the probiotic or synbiotic product. In general the study products were well tolerated. Overall, AEs occurred more frequent in the control arm compared to children receiving probiotics and/or synbiotics. Furthermore, the results indicate inadequate reporting and classification of AEs in the majority of the studies. In addition, generalizability of conclusions are greatly limited by the inconsistent, imprecise and potentially incomplete reporting as well as the variation in probiotic strains, dosages, administration regimes, study populations and reported outcomes.

Probiotics for preventing acute upper respiratory tract infections

BACKGROUND

Probiotics may improve a person's health by regulating their immune function. Some trials have shown that probiotic strains can prevent respiratory infections. Even though the previous version of our review showed benefits of probiotics for acute upper respiratory tract infections (URTIs), several new studies have been published.

OBJECTIVES

To assess the effectiveness and safety of probiotics (any specified strain or dose), compared with placebo, in the prevention of acute URTIs in people of all ages, at risk of acute URTIs.

SEARCH METHODS

We searched CENTRAL (2014, Issue 6), MEDLINE (1950 to July week 3, 2014), EMBASE (1974 to July 2014), Web of Science (1900 to July 2014), the Chinese Biomedical Literature Database, which includes the China Biological Medicine Database (from 1978 to July 2014), the Chinese Medicine Popular Science Literature Database (from 2000 to July 2014) and the Masters Degree Dissertation of Beijing Union Medical College Database (from 1981 to July 2014). We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for completed and ongoing trials on 31 July 2014.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing probiotics with placebo to prevent acute URTIs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and quality of trials, and extracted data using the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included 13 RCTs, although we could only extract data to meta-analyse 12 trials, which involved 3720 participants including children, adults (aged around 40 years) and older people. We found that probiotics were better than placebo when measuring the number of participants experiencing episodes of acute URTI (at least one episode: odds ratio (OR) 0.53; 95% confidence interval (CI) 0.37 to 0.76, P value < 0.001, low quality evidence; at least three episodes: OR 0.53; 95% CI 0.36 to 0.80, P value = 0.002, low quality evidence); the mean duration of an episode of acute URTI (mean difference (MD) -1.89; 95% CI -2.03 to -1.75, P value < 0.001, low quality evidence); reduced antibiotic prescription rates for acute URTIs (OR 0.65; 95% CI 0.45 to 0.94, moderate quality evidence) and cold-related school absence (OR 0.10; 95% CI 0.02 to 0.47, very low quality evidence). Probiotics and placebo were similar when measuring the rate ratio of episodes of acute URTI (rate ratio 0.83; 95% CI 0.66 to 1.05, P value = 0.12, very low quality evidence) and adverse events (OR 0.88; 95% CI 0.65 to 1.19, P value = 0.40, low quality evidence). Side effects of probiotics were minor and gastrointestinal symptoms were the most common. We found that some subgroups had a high level of heterogeneity when we conducted pooled analyses and the evidence level was low or very low quality.

AUTHORS' CONCLUSIONS

Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute URTI, the mean duration of an episode of acute URTI, antibiotic use and cold-related school absence. This indicates that probiotics may be more beneficial than placebo for preventing acute URTIs. However, the quality of the evidence was low or very low.

Probiotics or antibiotics: future challenges in medicine

Genetic and environmental factors can affect the intestinal microbiome and microbial metabolome. Among these environmental factors, the consumption of antibiotics can significantly change the intestinal microbiome of individuals and consequently affect the corresponding metagenome. The term 'probiotics' is related to preventive medicine rather than therapeutic procedures and is, thus, considered the opposite of antibiotics. This review discusses the challenges between these opposing treatments in terms of the following points: (i) antibiotic resistance, the relationship between antibiotic consumption and microbiome diversity reduction, antibiotic effect on the metagenome, and disease associated with antibiotics; and (ii) probiotics as living drugs, probiotic effect on epigenetic alterations, and gut microbiome relevance to hygiene indulgence. The intestinal microbiome is more specific for individuals and may be affected by environmental alterations and the occurrence of diseases.

Probiotics for the prevention of pediatric upper respiratory tract infections: a systematic review

BACKGROUND

Acute upper respiratory tract infections (URTIs) contribute substantially to pediatric morbidity and mortality worldwide. Prevention of these infections in childhood is a very important public health challenge. Previous systematic reviews, including both adult and childhood populations, have reported that probiotics seem promising, but with modest evidence. This study aimed to focus on prophylactic probiotic use in the prevention of URTIs in childhood.

METHODS

Relevant trials on two databases were identified in a systematic review, from inception to June 2014. Study selection, data extraction and quality assessment were carried out by two reviewers. In this review, the effects of probiotics, particularly the Lactobacillus and Bifidobacterium strains, on the incidence and symptom scores of URTI in otherwise healthy children were evaluated for the first time. This review comprises 14 randomized controlled trials (RCTs) applied to a pediatric population with high-quality methodology.

RESULTS

This systematic review suggests that probiotics in immunocompetent children have a modest effect both in diminishing the incidence of URTIs and the severity of the infection symptoms.

CONCLUSIONS

At least one beneficial effect of prophylactic probiotic was observed in the majority of RCTs. Even a minimal reduction of 5 - 10% in the incidence of URTIs would have an important clinical and economic mpact on societies. Furthermore, the long-term administration of probiotics appeared to have a good safety profile in childhood and none of the studies reported any serious adverse events related to the probiotic strain.

Effects of probiotic Lactobacillus brevis KB290 on incidence of influenza infection among schoolchildren: an open-label pilot study

We investigated the efficacy of dietary consumption of Lactobacillus brevis KB290 (KB290) against influenza in humans by a preliminary intervention study on elementary schoolchildren, using a commercially available probiotic drink. Subjects were divided into Groups A and B, and an open-label, parallel-group trial was conducted in two 8-week periods at a 1-month interval in winter 2013/2014. Group A was provided with a bottle of the test drink containing KB290 (about 6 billion colony-forming units) every school day in the first period and had no treatment in the second period, and vice versa for Group B. Epidemic influenza was not observed during the first period and only two of 1783 subjects were diagnosed. In the second period, the incidence of influenza in Groups A (no treatment) and B (provided the test drink) was 23·9 and 15·7%, respectively, and the difference was statistically significant (P < 0·001). The reduction in the incidence of influenza by KB290 consumption was especially remarkable in unvaccinated individuals. This is believed to be the first study to show a probiotic food reducing the incidence of influenza in schoolchildren, although further studies are needed to confirm the effectiveness of the probiotic strain KB290.

SIGNIFICANCE AND IMPACT OF THE STUDY

We demonstrated a reduction in the incidence of influenza in 1089 schoolchildren by continual intake of a probiotic drink containing Lactobacillus brevis KB290 (KB290), isolated from a traditional Japanese pickle 'Suguki'. The effect was especially evident in subjects not inoculated with influenza vaccine. This is believed to be the first report to show reduced incidence of influenza in schoolchildren taking a probiotic food. Further studies are needed to confirm the effectiveness of the probiotic strain KB290, which may be useful in the development of potential anti-influenza agents derived from common foods.

Probiotics and vitamin C for the prevention of respiratory tract infections in children attending preschool: a randomised controlled pilot study

Background:

This pilot study investigates the efficacy of a probiotic consortium (Lab4) in combination with vitamin C on the prevention of respiratory tract infections in children attending preschool facilities.

Subjects/methods:

In a double-blind, randomised, placebo-controlled pilot study with children aged 3–6 years, 57 received 1.25 × 10¹⁰ colony-forming units of Lactobacillus acidophilus CUL21 (NCIMB 30156), Lactobacillus acidophilus CUL60 (NCIMB 30157), Bifidobacterium bifidum CUL20 (NCIMB 30153) and Bifidobacterium animalis subsp. lactis CUL34 (NCIMB 30172) plus 50 mg vitamin C or a placebo daily for 6 months.

Results:

Significant reductions in the incidence rate of upper respiratory tract infection (URTI; 33%, P=0.002), the number of days with URTI symptoms (mean difference: −21.0, 95% confidence interval (CI):−35.9, −6.0, P=0.006) and the incidence rate of absence from preschool (30%, P=0.007) were observed in the active group compared with the placebo. The number of days of use of antibiotics, painkillers, cough medicine or nasal sprays was lower in the active group and reached significance for use of cough medicine (mean difference: −6.6, 95% CI: −12.9, −0.3, P=0.040). No significant differences were observed in the incidence rate ratio or duration of lower respiratory tract infection or in the levels of plasma cytokines, salivary immunoglobulin A or urinary metabolites.

Conclusions:

Supplementation with a probiotic/vitamin C combination may be beneficial in the prevention and management of URTIs.

Non-specific immune stimulation in respiratory tract infections. Separating the wheat from the chaff

Parents of children suffering from recurrent respiratory infections can be persuaded by advertisements to pressure their family physicians and pediatricians for "immune-stimulating enhancements". However, the evidence base behind these immune stimulants is usually lacking. Often there is no peer-reviewed studies available that support claims made by "immune-booster" supplements. In this review, we critically analyze most of the marketed immuno-active drugs (including vitamin preparations, dietary supplements, homeopathic remedies, Ecchinacea, bacterial lysates, and probiotics) and identify the necessity to exclude an immunodeficiency in every child suffering from recurrent respiratory tract infections.

Effectiveness of probiotics on the duration of illness in healthy children and adults who develop common acute respiratory infectious conditions: a systematic review and meta-analysis

Recent systematic reviews have reported a positive, although modest, effect of probiotics in terms of preventing common cold symptoms. In this systematic review, the effect of probiotics, specifically Lactobacillus and Bifidobacterium strains, on the duration of acute respiratory infections in otherwise healthy children and adults was evaluated. To identify relevant trials, eight databases, including MEDLINE, Embase, the Cochrane Database of Systematic Reviews (CDSR), the Cochrane Central Register of Controlled Trials (CENTRAL), the Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment (HTA), Science Citation Index (SCI) and OAISTER, were searched from inception to 20 July 2012. Details regarding unpublished studies/databases were also obtained from probiotic manufacturers. Study selection, data extraction and quality assessment were carried out by two reviewers. Risk of bias was assessed using criteria adapted from those published by the Centre for Reviews and Dissemination. In this review, twenty randomised controlled trials (RCT) were included, of which twelve were considered to have a low risk of bias. Meta-analysis revealed significantly fewer numbers of days of illness per person (standardised mean difference (SMD) - 0·31 (95% CI - 0·41, - 0·11), I²= 3%), shorter illness episodes by almost a day (weighted mean difference - 0·77 (95% CI - 1·50, - 0·04), I²= 80%) (without an increase in the number of illness episodes), and fewer numbers of days absent from day care/school/work (SMD - 0·17 (95% CI - 0·31, - 0·03), I²= 67%) in participants who received a probiotic intervention than in those who had taken a placebo. Reasons for heterogeneity between the studies were explored in subgroup analysis, but could not be explained, suggesting that the effect sizes found may differ between the population groups. This systematic review provides evidence from a number of good-quality RCT that probiotics reduce the duration of illness in otherwise healthy children and adults.

Do children's upper respiratory tract infections benefit from probiotics?

Background

The microbiota of the gastrointestinal tract have profound influence at multiple levels, even on the development and maintenance of lung immunity and inflammation. Aim of this review is to evaluate the current knowledge about the specific impact on children’s respiratory tract infections from probiotics, live microbes with the power to modify intestinal microbial populations and exert subsequent benefits for the host.

Discussion

The role of probiotics in gastrointestinal and allergic diseases has been largely assessed, but the number of studies performed so far in the field of respiratory tract infections is small, though some data show that probiotic administration might display clinical advantages. Probiotic strain identity and host genetic differences may account for differential modulation of immune responses by probiotics. Current laboratory and clinical data regarding the possibility of the role of probiotics on preventing the development of respiratory tract infections are contradictory, and are somewhat insufficient to recommend strongly their routine use. Further study of gastrointestinal-respiratory interactions is likely to yield important insights into the pathogenesis of different pulmonary diseases, and improve our knowledge in the prophylactic role of probiotics in children affected by recurrent upper respiratory tract infections.

Summary

A better understanding of the effects of different probiotic strains and a deeper insight into their mechanisms of action are needed for the validation of specific strains carrying a potential to modify the frequency and severity of RTIs in infants and children. No data have been collected in pediatric patients with chronic underlying diseases, and yet there are no published data concerning treatment of RTIs with probiotics. The very few studies published so far do not indicate which micro-organism or administration regimen might exert beneficial effects as a prevention tool of RTIs both in healthy children and in those with recurrent RTIs. Further research to establish the role of probiotics in the treatment and prevention of RTIs, including those involving the lower respiratory tract, are required and should also clarify if any susceptible subgroups of respiratory diseases exist, and how these subgroups benefit from supplementation with certain probiotic strains.

Probiotics in respiratory virus infections

Viral respiratory infections are the most common diseases in humans. A large range of etiologic agents challenge the development of efficient therapies. Research suggests that probiotics are able to decrease the risk or duration of respiratory infection symptoms. However, the antiviral mechanisms of probiotics are unclear. The purpose of this paper is to review the current knowledge on the effects of probiotics on respiratory virus infections and to provide insights on the possible antiviral mechanisms of probiotics. A PubMed and Scopus database search was performed up to January 2014 using appropriate search terms on probiotic and respiratory virus infections in cell models, in animal models, and in humans, and reviewed for their relevance. Altogether, thirty-three clinical trials were reviewed. The studies varied highly in study design, outcome measures, probiotics, dose, and matrices used. Twenty-eight trials reported that probiotics had beneficial effects in the outcome of respiratory tract infections (RTIs) and five showed no clear benefit. Only eight studies reported investigating viral etiology from the respiratory tract, and one of these reported a significant decrease in viral load. Based on experimental studies, probiotics may exert antiviral effects directly in probiotic–virus interaction or via stimulation of the immune system. Although probiotics seem to be beneficial in respiratory illnesses, the role of probiotics on specific viruses has not been investigated sufficiently. Due to the lack of confirmatory studies and varied data available, more randomized, double-blind, and placebo-controlled trials in different age populations investigating probiotic dose response, comparing probiotic strains/genera, and elucidating the antiviral effect mechanisms are necessary.

Supportive treatment for children with the common cold

PURPOSE OF REVIEW

This review summarizes recent developments in the supportive treatment of common cold symptoms in children.

RECENT FINDINGS

Conventional common cold therapies are no longer recommended for use in young children because of safety concerns. There are no studies that convincingly demonstrate the efficacy of any therapy for treatment of common cold symptoms in children less than 6 years of age and it is unlikely studies that establish efficacy can be done. Recent studies report a significant effect of probiotics on the occurrence of common cold illnesses in children, and studies in animals provide a plausible mechanism of action. These data suggest that the use of probiotics may have promise for the prevention of common cold illnesses in children.

SUMMARY

The effect of treatment on the severity of common cold symptoms cannot be accurately assessed with current study designs. In the absence of convincing evidence of efficacy, treatment of young children with symptomatic therapies cannot be recommended. Preliminary data suggest a small, beneficial effect of probiotics for the prevention of common cold illness.

Alteration of the intestinal microbiome: fecal microbiota transplant and probiotics for Clostridium difficile and beyond

Clostridium difficile infection is increasingly common with a high risk of recurrence despite antibiotic treatment. In cases of recurrent C. difficile infection, fecal microbiota transplant (FMT) is a highly effective treatment option promoting the restoration of normal gut microbiota. Furthermore, preliminary uncontrolled evidence demonstrates possible benefit of FMT in the management of some cases of inflammatory bowel disease and chronic constipation. In addition to presenting an overview of FMT, we discuss the role of probiotics, a more common approach to modifying the intestinal microbiome. Probiotics have been utilized broadly for many disease processes, including gastrointestinal, cardiovascular and allergic disease settings, although with limited and inconsistent results. Multiple potential areas for research are also identified.

Probiotics and Prevention of Pediatric Upper Respiratory Tract Infections

There is a certain consensus that some probiotics can significantly help in preventing and relieving the symptoms of gastrointestinal diseases and atopic diseases in general, but their use in respiratory tract infections has only been marginally investigated. The main aim of this review is to evaluate what is known about the impact of probiotics on pediatric respiratory tract infections in order to verify whether more data are needed before they can be used on infants and children with respiratory problems. Analysis of the literature shows that our knowledge is limited to the prevention of upper respiratory tract infections (URTIs). The very few studies carried out so far seem to indicate that probiotic administration may have some advantages in this regard, but the great limitation is that nothing is known about the susceptible micro-organisms or treatment regimens. Furthermore, URTIs are very limited clinical problems and it seems unreasonable to use a treatment whose efficacy and safety has not been completely clarified as means of preventing them. No data are available concerning the treatment of URTIs. There is a need for further research into the role of probiotics in treating respiratory infections and preventing more severe respiratory problems, including those involving the lower respiratory tract.

An update on the use and investigation of probiotics in health and disease

Probiotics are derived from traditional fermented foods, from beneficial commensals or from the environment. They act through diverse mechanisms affecting the composition or function of the commensal microbiota and by altering host epithelial and immunological responses. Certain probiotic interventions have shown promise in selected clinical conditions where aberrant microbiota have been reported, such as atopic dermatitis, necrotising enterocolitis, pouchitis and possibly irritable bowel syndrome. However, no studies have been conducted that can causally link clinical improvements to probiotic-induced microbiota changes. Whether a disease-prone microbiota pattern can be remodelled to a more robust, resilient and disease-free state by probiotic administration remains a key unanswered question. Progress in this area will be facilitated by: optimising strain, dose and product formulations, including protective commensal species; matching these formulations with selectively responsive subpopulations; and identifying ways to manipulate diet to modify bacterial profiles and metabolism.

Characterization of fecal microbiota of children with diarrhea in 2 locations in Colombia

OBJECTIVES

Diarrhea is a leading cause of mortality and morbidity in children younger than 5 years in impoverished regions of the world. Our aim was to compare the fecal microbiota of healthy children with that of children with clinical diarrhea in a population from a tropical highland in Colombia, South America. Our hypothesis was that a reduced prevalence of inherent Lactobacillus and Bifidobacterium species would be associated with enteric viral and bacterial pathogens.

METHODS

Children between 1 and 5 years of age from 2 different locations were evaluated for presence of clinical diarrhea. Nucleic acid, isolated from fecal samples, was used to determine by molecular protocols the abundance of inherent bacterial species and presence of enteric pathogens compared with clinically healthy children. The effect of host demographic factors on incidence of diarrhea was also analyzed.

RESULTS

: The composition of the fecal microbiota was affected by host demographic factors: age, health status, location, and sex. In partial support of our hypothesis, the relative abundance of commensal Bifidobacterium and Lactobacillus species was inversely correlated with incidence of diarrhea regardless of location.

CONCLUSIONS

Our results suggested that changes in fecal microbiota composition of children with clinical diarrhea are associated with certain demographic factors that should be considered before designing a prophylactic intervention. Delivery of certain Lactobacillus species and Bifidobacterium species or a diet rich in bifidogenic components that promote growth of Bifidobacterium species could provide a prophylactic effect to ameliorate the effect of diarrhea in children at risk.

Randomized controlled trial of probiotics to reduce common cold in schoolchildren

BACKGROUND

The common cold is responsible for the largest proportion of school and work absenteeism and causes a huge economic burden. None of the current interventions is greatly effective for prevention. Our aim was to assess the efficacy of a two-strain combination probiotic for prevention of common cold symptoms in healthy schoolchildren.

METHODS

A double-blind randomized controlled trial was performed during the winter season in a public school of central Thailand. Children, aged 8-13 years, were randomized to receive either a two-strain combination probiotic (Lactobacillus acidophilus and Bifidobacterium bifidum) or placebo given twice a day for 3 months. The primary outcome was any symptom of cold during the 3-month study period while vomiting, diarrhea, use of antibiotics, school absence due to any cause, school absence due to cold and duration of all symptoms were secondary outcomes.

RESULTS

Of the 40 children in each group, 31 (77%) in the probiotic group, compared to 38 (95%) in the placebo group (P= 0.048), developed at least one symptom of cold. Children in the probiotics group had significantly lower risk of fever, cough, rhinorrhea, school absence and school absence related to common cold compared to children in the placebo group. There was no impact on diarrhea and vomiting.

CONCLUSION

A two-strain probiotic combination given twice a day for 3 months was able to reduce the symptoms of the common cold and school absenteeism in schoolchildren.

Respiratory viral infections in children with asthma: do they matter and can we prevent them?

BACKGROUND

Asthma is a major public health problem with a huge social and economic burden affecting 300 million people worldwide. Viral respiratory infections are the major cause of acute asthma exacerbations and may contribute to asthma inception in high risk young children with susceptible genetic background. Acute exacerbations are associated with decreased lung growth or accelerated loss of lung function and, as such, add substantially to both the cost and morbidity associated with asthma.

DISCUSSION

While the importance of preventing viral infection is well established, preventive strategies have not been well explored. Good personal hygiene, hand-washing and avoidance of cigarette smoke are likely to reduce respiratory viral infections. Eating a healthy balanced diet, active probiotic supplements and bacterial-derived products, such as OM-85, may reduce recurrent infections in susceptible children. There are no practical anti-viral therapies currently available that are suitable for widespread use.

SUMMARY

Hand hygiene is the best measure to prevent the common cold. A healthy balanced diet, active probiotic supplements and immunostimulant OM-85 may reduce recurrent infections in asthmatic children.

Beneficial effects of probiotics in upper respiratory tract infections and their mechanical actions to antagonize pathogens

Probiotics are live micro‐organisms with beneficial effects on human health, which have the ability to counteract infections at different locations of the body. Clinical trials have shown that probiotics can be used as preventive and therapeutic agents in upper respiratory tract infections (URTIs) and otitis. Their mechanical properties allow them to aggregate and to compete with pathogens for nutrients, space and attachment to host cells. Consequently, they can directly antagonize pathogens and thus exert beneficial effects without directly affecting the metabolism of the host. An overview of the probiotics with such traits, tested up to date in clinical trials for the prevention or treatment of URTIs and otitis, is presented in this review. Their mechanical properties in the respiratory tract as well as at other locations are also cited. Species with interesting in vitro properties towards pharyngeal cells or against common respiratory pathogens have also been included. The potential safety risks of the cited species are then discussed. This review could be of help in the screening of probiotic strains with specific mechanical properties susceptible to have positive effects in clinical trials against URTIs.

Lysate of probiotic Lactobacillus casei DN-114 001 ameliorates colitis by strengthening the gut barrier function and changing the gut microenvironment

Background

Probiotic bacteria can be used for the prevention and treatment of human inflammatory diseases including inflammatory bowel diseases (IBD). However, the nature of active components and exact mechanisms of this beneficial effects have not been fully elucidated. Our aim was to investigate if lysate of probiotic bacterium L. casei DN-114 001 (Lc) could decrease the severity of intestinal inflammation in a murine model of IBD.

Methodology/Principal Findings

The preventive effect of oral administration of Lc significantly reduces the severity of acute dextran sulfate sodium (DSS) colitis in BALB/c but not in SCID mice. In order to analyze how this beneficial effect interferes with well-known phases of intestinal inflammation pathogenesis in vivo and in vitro, we evaluated intestinal permeability using the FITC-labeled dextran method and analysed tight junction proteins expression by immunofluorescence and PCR. We also measured CD4⁺FoxP3⁺ regulatory T cells proportion by FACS analysis, microbiota composition by pyrosequencing, and local cytokine production by ELISA. Lc leads to a significant protection against increased intestinal permeability and barrier dysfunction shown by preserved ZO-1 expression. We found that the Lc treatment increases the numbers of CD4⁺FoxP3⁺ regulatory T cells in mesenteric lymph nodes (MLN), decreases production of pro-inflammatory cytokines TNF-α and IFN-γ, and anti-inflammatory IL-10 in Peyer's patches and large intestine, and changes the gut microbiota composition. Moreover, Lc treatment prevents lipopolysaccharide-induced TNF-α expression in RAW 264.7 cell line by down-regulating the NF-κB signaling pathway.

Conclusion/Significance

Our study provided evidence that even non-living probiotic bacteria can prevent the development of severe forms of intestinal inflammation by strengthening the integrity of intestinal barrier and modulation of gut microenvironment.

The association of mode of delivery and common childhood illnesses

Participants enrolled in a randomized control trial (RCT) were eligible for this cross-sectional study to determine if children born via cesarean (C)-section had higher rates of common infectious diseases and change in normal daily activities due to illness than children born vaginally. The RCT collected parent-reported health information and mode of delivery was assessed during follow-up calls. Parent-reported rates of infectious sequelae and changes in daily activities were compared between C-section and vaginally delivered children. In total, 72.4% of the 522 children were delivered vaginally. After accounting for age, siblings, breast-feeding as an infant, and clustering within families, C-section delivered children had significantly higher rates of cumulative infectious diseases, lower respiratory tract infections, and cough than vaginally born children. Mode of delivery appears to have some lasting effect on child health 3 to 6 years after birth, specifically respiratory health. Further research is imperative to elucidate the causative effect of mode of delivery on child health.

Probiotics for preventing acute upper respiratory tract infections

BACKGROUND

Probiotics may improve a person's health by regulating their immune function. Some studies show that probiotic strains can prevent respiratory infections. However, no evidence of the benefits of probiotics for acute upper respiratory tract infections (URTIs) and related potential adverse effects has been published.

OBJECTIVES

To assess the effectiveness and safety of probiotics for preventing acute URTIs.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (Ovid) (1950 to May week 1, 2011), EMBASE (1974 to May 2011), Web of Science which includes Science Citation Index (from 1900 to May 2011) and Conference Proceedings Citation Index (from 1991 to May 2011), the Chinese Biomedical Literature Database, which includes the China Biological Medicine Database (from 1978 to May 2011), the Chinese Medicine Popular Science Literature Database (from 2000 to May 2011) and the Masters Degree Dissertation of Beijing Union Medical College Database (from 1981 to May 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing probiotics with placebo to prevent acute URTIs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility, quality of trials and extracted data.

MAIN RESULTS

We included 14 RCTs, although we could only extract available data to meta-analyse in 10 trials which involved 3451 participants. We found that probiotics were better than placebo when measuring the number of participants experiencing episodes of acute URTI: at least one episode: odds ratio (OR) 0.58; 95% confidence interval (CI) 0.36 to 0.92; at least three episodes: OR 0.53; 95% CI 0.36 to 0.80; rate ratio of episodes of acute URTI: rate ratio 0.88; 95% CI 0.81 to 0.96; and reduced antibiotic prescription rates for acute URTIs: OR 0.67; 95% CI 0.45 to 0.98. Probiotics and placebo were similar when measuring the mean duration (MD) of an episode of acute URTI: MD -0.29; 95% CI -3.71 to 3.13 and adverse events: OR 0.92; 95% CI 0.37 to 2.28. Side effects of probiotics were minor and gastrointestinal symptoms were the most common. We found that some subgroups had a high level of heterogeneity when conducting pooled analyses.

AUTHORS' CONCLUSIONS

Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute URTIs, the rate ratio of episodes of acute URTI and reducing antibiotic use. This indicates that probiotics may be more beneficial than placebo for preventing acute URTIs. However, the results have some limitations and there were no data for older people.

Evaluation of the immune benefits of two probiotic strains Bifidobacterium animalis ssp. lactis, BB-12® and Lactobacillus paracasei ssp. paracasei, L. casei 431® in an influenza vaccination model: a randomised, double-blind, placebo-controlled study

The present study investigated the ability of Bifidobacterium animalis ssp. lactis (BB-12®) and Lactobacillus paracasei ssp. paracasei (L. casei 431®) to modulate the immune system using a vaccination model in healthy subjects. A randomised, double-blind, placebo-controlled, parallel-group study was conducted in 211 subjects (56 % females, mean age 33·2 (sd 13·1) years). Subjects consumed a minimum of 10⁹ colony-forming units of BB-12® (capsule) or L. casei 431® (dairy drink) or a matching placebo once daily for 6 weeks. After 2 weeks, a seasonal influenza vaccination was given. Plasma and saliva samples were collected at baseline and after 6 weeks for the analysis of antibodies, cytokines and innate immune parameters. Changes from baseline in vaccine-specific plasma IgG, IgG1 and IgG3 were significantly greater in both probiotic groups v. the corresponding placebo group (L. casei 431®, P = 0·01 for IgG; P < 0·001 for remaining comparisons). The number of subjects obtaining a substantial increase in specific IgG (defined as ≥ 2-fold above baseline) was significantly greater in both probiotic groups v. placebo (BB-12®, P < 0·001 for IgG, IgG1 and IgG3; L. casei 431®, P < 0·001 for IgG1 and IgG3). Significantly greater mean fold increases for vaccine-specific secretory IgA in saliva were observed in both probiotic groups v. placebo (BB-12®, P = 0·017; L. casei 431®, P = 0·035). Similar results were observed for total antibody concentrations. No differences were found for plasma cytokines or innate immune parameters. Data herein show that supplementation with BB-12® or L. casei 431® may be an effective means to improve immune function by augmenting systemic and mucosal immune responses to challenge.