REVIEW ARTICLE
The use of Probiotics to Prevent Diarrhea in Young Children Attending
Child Care Centers: A Review
Colin Binns
1,*, Mi Kyung Lee
21School of Public Health and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia 2School of Chiropractic and Sports Science, Murdoch University, Perth, Australia
a r t i c l e i n f o
Article history: Received: Apr 8, 2010 Revised: Jul 18, 2010 Accepted: Aug 15, 2010 Available online 20 October 2010 KEY WORDS: children; diarrhea; prebiotics; prevention; probiotics
The incidence of diarrheal disease in children has been reduced because of public health measures, improved hygiene, and a better understanding of nutrition. However, it remains a particular problem where young children come into close contact with other children, such as in child day care centers. Probiotics are defined as products that contain an adequate dose of live microbial agents that have been shown in target-host studies to confer a health benefit. They have been used for the treatment and prevention of many diseases, but particularly of gastrointestinal diseases. Prebiotics are inactive food components, commonly oligosaccharides or polysaccharides, that stimulate growth of beneficial bacteria in the gastrointestinal tract and are commonly used in combination with probiotics.
The initial searches identified 5860 articles from the PubMed database, but only 154 included the keyword “trial.” Probiotics share the problem of limited systematic research with other traditional medications and foods, and only seven studies were included in thefinal analysis. A variety of probiotic organisms and prebiotics were used in the studies, and the end points were not standardized. However, examination of the six studies that used live cultures showed thatfive studies resulted in a decrease in either the number of episodes or the duration of diarrhea or both. However, the studies support a reduction of around 20% in diarrheal episodes or days of illness. Findings of this review have important implications for working parents. The regular use of a probiotic or probiotic/prebiotic combination will reduce the incidence and duration of diarrheal disease in children attending childcare centers (risk ratio, 0.72e0.82). Further research is needed to better define the most effective probiotic organisms and the optimal dosage.
CopyrightÓ 2010, Taipei Medical University. Published by Elsevier Taiwan LLC. All rights reserved.
1. Introduction
Diarrheal disease remains an important cause of morbidity and mortality throughout our region, and despite advances in nutrition and hygiene, the incidence remains high. Probiotics have been used for the treatment and prevention of many diseases, but particularly of gastrointestinal diseases. Benefits have been found for the use of probiotics in the prevention of antibiotic-induced diarrhea and in the management of necrotizing enterocolitis, travelers’ diarrhea, and diarrhea in infants.1In this article, we will review the use of probiotics in the prevention of diarrheal disease in children and in particular those who spend at least part of the day in a childcare center.
In many traditional societies, all adults in the family are required to work to provide for food and additional income. In these
extended families, children are cared for by grandparents or other children old enough to provide some care, but not yet old enough to work in thefields. In the 21stcentury, family structures and work
patterns have changed in both developed and developing coun-tries. This has resulted in changes in childcare practices and the exposure of children to additional risks of infection at earlier ages. Although substantial progress has been made in improving child health, there are still many children who die from preventable causes. Each year, an estimated 9 million children die before their 5th birthday, and diarrheal disease remains one of the top two causes of morbidity and mortality in children in the Asia Pacific region and worldwide.2 Many of these children will have been cared for in the least part of their lives by other members of the family or in formal childcare, as modern lifestyles have often led to both parents being absent from the home during the day for employment, particularly in the rapidly growing cities. Children are then cared for in other homes, day care homes, or formal or informal childcare day centers.
Any place that children congregate together has increased rates of infectious disease.3Children are susceptible hosts and often have * Corresponding author. School of Public Health, Curtin Health Innovation
Research Institute, Curtain University, GPO Box U1987, Perth, Western Australia 6845, Australia E-mail:
E-mail:c.binns@curtin.edu.au(C. Binns).
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less-than-ideal personal hygiene habits. Staff are required to provide frequent personal care with the opportunity of spreading infection to all the groups. It is hardly surprising that childcare facilities are classified as a hazardous workplace for staff because of an increased prevalence of infectious disease and musculoskeletal problems from lifting.4 Childcare centers have shown increased rates of diarrhea, respiratory tract infections, hepatitis A, Haemo-philus influenzae, and many other childhood illnesses.3,5e7
To meet the need for continuing care, a network of childcare centers has been established in Australia and other western countries, and the system is now spreading to all countries throughout our region. These centers provide an invaluable service to parents who work and who do not have access to carers in the extended families of previous generations. But the increased risk of childhood diseases has its consequences for the family, as infection may spread to other children and family members once the child returned home. The exclusion of unwell children from attending childcare centers causes considerable inconvenience for working parents. There is also a substantial economic impact through the direct health care costs and parents having to take time off work to look after their sick child.8
Diarrheal disease is a particular risk in these centers and has been the subject of many studies.9e15In Australia, higher levels of infection led to the publication of national guidelines, which have resulted in a considerable improvement in hygiene standards.16 The guidelines for centers in Australia (and most other coun-tries) are conservative, and any child diagnosed with diarrhea is excluded from childcare centers. The working definition of diar-rhea used by childcare centers and parents is based on consis-tency of stools and the number of stools per day, but particularly the latter.
Interventions for the prevention of diarrhea include the promotion of breastfeeding, improved nutrition and the availability of clean water supplies.17,18Frequent and careful washing of hands by staff and attention to hygiene are important preventive measures in childcare centers.19e22
Probiotics have been consumed by humans since time imme-morial, in the form of fermented milks, yogurts, and other fer-mented foods. They have commonly been used to treat a variety of gastrointestinal complaints. The type of fermented product used depends on the availability in the particular culture. For example in Korea, where dairy products were less readily available, the health benefits of kimchi (fermented vegetable products with lactobacilli) have been widely proclaimed.
The Russian microbiologist, Ilya Metchnikov, who received the 1908 Nobel prize in medicine for his discovery of the process of phagocytosis, formalized the concept of“probiotics,” a Greek word meaning“for life,” more than a century ago. He introduced the term “probiotic” to describe live microbial supplements designed to improve“health.” While working at the Pasteur Institute in Paris, he promoted the use of fermented milk (lactobacilli) to promote health.23Metchnikov provided thefirst scientific explanation of the beneficial effects of yogurt when he suggested that lactic acid produced by lactobacilli could inhibit the growth of“unhealthy” bacterial species. There are several more recent definitions of probiotics in common use including“live microorganisms which, when administered in adequate amounts, confer a health benefit on the host” or “live viable microorganisms that, when taken by mouth, exert beneficial effects upon the host.”23 However, Sanders24recommends that the term“probiotic” be restricted in use to products that meet specific scientific criteria, namely prod-ucts that contain an adequate dose of live microbial agents that have been shown in target-host studies to confer a health benefit. Probiotics may be used alone or combined with prebiotics.25 Prebiotics are inactive food components that stimulate growth of
beneficial bacteria in the gastrointestinal tract (GIT) and potentially have benefits on human health.26Prebiotics are defined as “non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth, and/or activity, of one or a limited number of beneficial bacteria in the colon and thus improve host health.”27Prebiotics may be nondigestible carbohy-drates (oligosaccharides or polysaccharides), protein, peptides, or some types of lipid. Wang and Gibson28demonstrated that, in the presence of fructo-oligosaccharides, bifidobacteria grew better than bacteroides, clostridia, or coliforms. Prebiotics are generally considered to be safe as they are naturally present in several kinds of food, but overconsumption in humans can lead toflatulence, bloating, and diarrhea. A product used by humans that contains a mixture of probiotics and prebiotics is often referred to as a“synbiotic.” Breast milk contains natural prebiotics, human milk oligosaccharides, which explains the bifidobacteria-dominated microflora seen in breastfed infants.
A mature adult human has approximately 10 times more bacteria than human cells, and the composition and quantification has been the subject to research since bacteria werefirst system-atically described.29At birth, the GIT is sterile, but it soon colonized from external sources, particularly the maternal genitourinary tract and gradually stabilizes over the next 18 months.26,30Colonization depends on environmental factors, such as the method of infant feeding and the level of hygiene, and becomes more like an adult flora as the child begins to consume solid foods. Other factors that influence the colonization pattern include the mode of delivery (vaginal delivery vs. cesarean section), gestational age (prematu-rity), length of hospitalization, antibiotic use after birth, and exposure to older siblings and other children. The normal gutflora in the adult contains about 500 species existing in a synbiotic relationship with the host.26Recognizing the importance of our microbiological load to human health, the National Institutes of Health is now midway through the 5-year Human Microbiome Project as part of its Roadmap for Medical Research. The advent of modern analytical systems has enabled this project to proceed and has revealed significant variation in the microbiological flora of the gastrointestinal luminal contents and the mucosal community composition.31The ultimate aim of this research is to modify the human microbiome through specifically targeted antibiotics with probiotics and prebiotics to promote optimal health.32
The microflora of the GIT has several important nutritional functions, including protection of the GIT against epithelial injury, protection against infection from noncommensal microbes, stim-ulation of immune functions, regstim-ulation of host fat storage, and stimulation of intestinal angiogenesis.31The role of intestinalflora in the degradation of indigestible dietary carbohydrates has become of interest with the current worldwide obesity epidemic. It has been postulated that changes in energy availability may be a function of each persons’ microbiome, and this could be a factor in the etiology of obesity.33,34
The specific aim of this article is to review the use of probiotics and prebiotics, usually in combination, in the prevention of community-acquired diarrheal disease in children, and in partic-ular those who spend at least part of the day in a childcare center. 2. Methodology
The databases that were searched to compile this review were PubMed, ScienceDirect, CINAHL, the Cochrane Library, and Web of Knowledge. In addition, reference lists of the articles obtained during the search were reviewed. The search was restricted to English language publications and used the following search terms: diarrhoea (diarrhea) children (child), prevention, and probiotics. Full articles were retrieved and evaluated where the article
included children aged less than 4 years, and the paper reported a prevention study in community-dwelling children attending child day care centers. Exclusions included trials reporting the treatment of diarrhea or the prevention of side effects while chil-dren were under treatment, such as the prevention of diarrhea in children being treated with antibiotics. Articles from developing countries were excluded as many of these used samples that included children with malnutrition or who were likely to be exposed to high levels of infection. The selected articles were also followed up in Science Citations (Web of Knowledge) tofind further relevant studies and reviews.
3. Results
The initial searches revealed a large number of publications related to probiotics; approximately 5860 articles were found in PubMed, but only 154 included“trial.” The vast majority of articles were uncontrolled trials, case studies, discussions, and nonsystematic reviews. Probiotics share the problem of limited systematic research with other traditional medications and foods. The limited opportunities for commercial patents and the difficulty of research, including the need for daily doses of probiotics, have resulted in fewer trials than would be expected. However, included in the array of literature on probiotics in general are 18 Cochrane reviews and 4 Cochrane protocols. The Cochrane reviews included the use of probiotics in the prevention and treatment of antibiotic-induced diarrhea, but none are on the prevention of diarrhea in children living in the community. SeeTable 1for details of the Cochrane reviews that have found positive benefits for the use of probiotics. Two areas where Cochrane reviews have shown no benefit in the use of probiotics in children have been in the prevention of allergies and prevention of irritable bowel syndrome.44,45 There were 95 articles that were found using the search words trial, diarrhoea, and child. But after reading the full texts, only seven articles were found that could be included in this review.
In addition to the Cochrane reviews, further systematic litera-ture reviews related to probiotics and diarrhea were located in other refereed (peer-reviewed) journals. A systematic review by Szajewska et al35included trials on prevention, but in this review, only three studies were considered with sample sizes of 10, 15, and 204. The latter study was in Peru among undernourished indigent children.36
Lewis and Freedman37 reviewed the use of probiotics in the prevention of diarrhea and concluded:“There is a plethora of data on probiotics from in vitro and animal experiments; with the exception of diarrhea due to rotavirus infection in children, there is little evidence from randomized studies that probiotics have
a significant beneficial action in preventing diarrhea of any cause.” Their review included mostly studies on the use of probiotics for the treatment of diarrhea and only one study of prevention in children. In the most comprehensive meta-analysis of probiotic use in the prevention of diarrhea, of 690 studies identified by Sazawal et al,38only 28 met the criteria for inclusion in the review. But they included only one trial of community-acquired diarrhea in children, the trial from Peru referred to above.36However, they concluded that “although there is some suggestion that probiotics may be efficacious in preventing acute diarrhea, there is a lack of data from community-based trials,” a conclusion well warranted since only one trial was reviewed.
Minocha39 reviewed the use of probiotics in children in day care centers using data from two trials and suggested that probiotics may promote good health in day care centers. A review of the use of prebiotics, including inulin, oligofructose, and galactooli-gosaccharides found no evidence to“recommend prebiotics for the prevention of diarrhea.”40Although some evidence has been found for the use of probiotics to prevent traveler’s diarrhea, a major systematic review found that no studies had been undertaken in children.41
Details of the seven randomized clinical trials that met the criteria for inclusion in this study are shown inTable 2. In one case, the study reported a trial of fermented milk, where the probiotic had been inactivated by processing, and the study showed no effect.42A variety of probiotic organisms and prebiotics were used in the studies. The end points, including the definitions of diarrhea were not standardized, but most trials used an intention-to-treat analysis. The lack of standardization makes meta-analysis difficult. However, an examination of the six studies that used live cultures shows that five resulted in a decrease in either the number of episodes or the duration of diarrhea or both. No quantitative esti-mate of effect can be given because of the variety of end points used. However, the studies support an effect of the magnitude found in the CUPDAY Study, a reduction of around 20% in diarrheal episodes or days of illness.43
4. Discussion
Children are usually excluded from childcare centers when they develop any illness, even a relatively minor one. Diarrheal disease almost always results in automatic exclusion until the illness episode has passed. Improved hygiene in childcare centers has been shown to reduce the rates of diarrheal disease.12This is a problem of concern to parents with young children, and the use of probiotics provides a possible solution.
Table 1 Cochrane reviews of the use of probiotics in children
Cochrane review Conclusion
AlFaleh KM, Bassler D. Probiotics for prevention of necrotizing enterocolitis in preterm infants. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD005496. DOI:10.1002/14651858.CD005496.pub2.
Enteral supplementation of probiotics reduced the risk of severe necrotizing enterocolitis and mortality in preterm infants. This analysis supports a change in practice in premature infants>1000 g at birth. Allen SJ, Okoko B, Martinez EG, Gregorio GV, Dans LF. Probiotics for
treating infectious diarrhea. Cochrane Database of Systematic Reviews 2003, Issue 4. Art. No.: CD003048.
DOI:10.1002/14651858.CD003048.pub2.
Probiotics appear to be a useful adjunct to rehydration therapy in treating acute infectious diarrhea in adults and children.
Johnston BC, Supina AL, Ospina M, Vohra S. Probiotics for the prevention of pediatric antibiotic-associated diarrhea. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD004827. DOI:10.1002/14651858.CD004827.pub2.
The per-protocol analysis for 9/10 trials reporting on the incidence of diarrhea shows statistically significant results favoring probiotics over active/nonactive controls (RR: 0.49; 95% CI: 0.32e0.74). However, intention-to-treat analysis showed nonsignificant results overall (RR: 0.90; 95% CI: 0.50e1.63).
In the studies that reached the criteria for inclusion in the review, there were several different probiotic organisms used, and a variety of end points measured. The most common probiotics were from the lactobacilli group of lactase-producing bacteria (e.g., Lactobacillus acidophilus) and bifidobacteria. There were also differences in the use of prebiotics, in type and quantity, as part of the preventive regime. To be effective, probiotics must be administered on a regular basis, probably at least daily and must be acid stabile, have an ability to colonize the intestine, and bring health benefits to the host, and all of the preparations used met these criteria. The requirement for daily administration places a burden on parents and carers and explains the dropout rates in some of the studies.
From the heterogeneous studies available, which together include approximately 540,000 child-days of preschool-aged chil-dren, a few conclusions can be drawn. Thefirst conclusion is that in
all the articles, there was a concern about the risk of infection in children attending childcare. In the modern era, illness of children has a significant impact on the family dynamics and is of economic importance, as parents have to take time off work to care for their ill child. The studies regarded the probiotic combinations used to be safe, and few side effects were reported. The second conclusion is that overall probiotics are effective in reducing the rate of diarrhea in children attending childcare centers, probably at least a 20% reduction in episodes and days of significant illnesses. No state-ment can be made from the available evidence as to which combination of probiotics and prebiotics is the most effective. Similarly, no statement can be made on the most effective daily dose to be used. More research is required to define the most effective probiotics and whether (and which) prebiotics should be included and the optimal dosage schedule for prevention. Table 2 Summary of randomized, double-blind, placebo-controlled prevention trials of probiotics for diarrhea prevention in children
Trial Location Inclusion criteria Exclusion criteria Age (mo)
Pedone (1999) France Child day care facilities; N¼ 287
Long-term medication, breastfed, allergy, malabsorption
12e24 Pedone (2000) France Child day care facilities;
multicenter, N¼ 928 healthy children attending day care 5 days/wk
Long-term medication, breastfed, allergy, malabsorption
6e24
Hakatta (2001) Finland Children aged attending municipal day care centers in Helsinki; N¼ 571
History allergy to cow’s milk, lactose intolerance, severe food allergy, and severe chronic disease
12e72
Saavedra (2004) USA Healthy children attending day care in Baltimore; N¼ 131 healthy children
Breastfed GIT disease or allergy 3e24
Thibault (2004) France Healthy infants attending childcare centers or>2 siblings at home; N¼ 968
Breastfed; on special diets; had chronic diarrhea
4e6
Wiezman (2005) Israel Infants attending childcare centers; N¼ 201 healthy term infants
Chronic illness medication 4e10
Giovanni (2007) Italy Preschool children with allergic asthma/rhinitis; N¼ 187
Chronic illness medication 24e60 Binns (2007) Australia Healthy children attending day
care centers in Perth
Allergy to milk products, chronic diarrhea
12e36
Probiotic strain Dose Intervention Outcomes Type of diarrhea Results
Lactobacillus casei 108cfu/mL,
125 or 250 g according to age
For the duration of hospital stay with formula
Episodes of disease; duration of diarrhea
Nosocomial Reduced duration of diarrheal episodes L bulgaris & S thermophilus or Lactobacillus casei 107cfu/g, or 3.2 108cfu/g Comparison of two types of yogurt/ fermented milks
Duration of diarrhea Community acquired Reduced number of episodes in Group 2. (RR¼ 0.72), duration: NS Lactobacillus rhamnosus GG 5e10 105, 200 mL milk per day RCT for 7 mo over winter Incidence of diarrhea; and other GIT and respiratory symptoms Number of days with symptoms
Community acquired Decreased days absent, respiratory and GI symptoms and reduced antibiotics
Lactobacillus bifidus BB12
107cfu/g 18 mo Health and GIT
symptoms
Community acquired Antibiotic use decreased, diarrhea NS Lactobacillus bifidus
BBC50
Fermented formula, no live bacteria
RCT for 5 mo Health and GIT symptoms
Community acquired No difference incidence, duration of diarrhea episodes, and hospital admissions Lactobacillus bifidus
BB12 or Lactobacillis reuteri
107cfu/g RCT 21 mo, control
plus 2 trial groups
Illness episodes including diarrhea
Community acquired Episodes of diarrhea reduced by>50% Lactobacillus casei 108cfu/mL,
100 mL/d
RCT for 12 mo Duration of episodes of diarrhea
Community acquired Duration of episodes of diarrhea was shortened by 0.8 days
Bifidobacterium lactis (BL: CNCM I-3446) and a prebiotic blend
2.109/100 g, dry weight RCT for 7 mo over winter Number of episodes of diarrhea
Community acquired Number of episodes of diarrhea reduced RR 0.82 (0.73e0.94) GIT¼ gastrointestinal tract; RR ¼ relative risk; NS ¼ not significant; RCT ¼ randomized controlled trial.
5. Conclusions
Findings of this study have important implications for working parents. Evidence from the trials reviewed in this study show that the regular use of a probiotic or probiotic/prebiotic combination will reduce the incidence and duration of diarrheal disease in children attending childcare centers. Further research is needed to better define the most effective probiotic organisms and optimal dosage.
References
1. Wolvers D, Antoine JM, Myllyluoma E, Schrezenmeir J, Szajewska H, Rijkers GT. Guidance for substantiating the evidence for beneficial effects of probiotics: prevention and management of infections by probiotics. J Nutr 2010;140: 698Se712.
2. You D, Wardlaw T, Salama P, Jones G. Levels and trends in under-5 mortality, 1990e2008. Lancet 2010;375:100e3.
3. Pickering LK. Infectious diseases in child day care facilities. Infect Dis Newslett 1986;5:76e8.
4. Centers for Disease Control. The ABS’s of Safe and Healthy Child Care: A Handbook for Child Care Providers: Department of Health and Human Services. Atlanta: U.S. Public Health Service, Centers for Disease Control and Prevention; 1996. 5. Van R, Wun C-C, O’Ryan ML, Matson DO, Jackson L, Pickering LK. Outbreaks of
human enteric adenovirus types 40 and 41 in Houston day care centers. J Pediatr 1992;120(4 Pt 1):516e20.
6. Louhiala PJ, Jaakkola N, Ruotsalainen R, Jaakkola JJK. Day-care centers and diarrhea: a public health perspective. J Pediatr 1997;131:476e9.
7. Kahan E, Gross S, Cohen HA. Exclusion of ill children from child-care centers in Israel. Patient Educ Couns 2005;56:93e7.
8. Carabin H, Gyorkos T, Soto J, Penrod J, Joseph L, Collet J. Estimation of direct and indirect costs because of common infections in toddlers attending day care centers. Pediatrics 1999;103:556e64.
9. Bartlett AV, Moore M, Gary GW, Starko KM, Erben JJ, Meredith BA. Diarrheal illness among infants and toddlers in day care centers. II. Comparison with day care homes and households. J Pediatr 1985;107:503e9.
10. Bartlett AV, Moore M, Gary GW, Starko KM, Erben JJ, Meredith BA. Diarrheal illness among infants and toddlers in day care centers. I. Epidemiology and pathogens. J Pediatr 1985;107:495e502.
11. Vu Nguyen T, Le Van P, Le Huy C, Nguyen Gia K, Weintraub A. Etiology and epidemiology of diarrhea in children in Hanoi, Vietnam. Int J Infect Dis 2006;10: 298e308.
12. Thompson S. Infectious diarrhoea in children: controlling transmission in the child care setting. J Paediatr Child Health 1994;30:210e9.
13. Izzuddin Poo M, Lee WS. Admission to hospital with childhood acute gastro-enteritis in Kuala Lumpur, Malaysia. Med J Malaysia 2007;62:189e93. 14. Persson K, Svenungsson B, de Jong B. An outbreak of cryptosporidiosis at a
day-care centre in Sweden. Euro Surveill 2007;12. E070823.3.
15. Zutavern A, Rzehak P, Brockow I, Schaaf B, Bollrath C, von Berg A, Link E, et al. Day care in relation to respiratory-tract and gastrointestinal infections in a German birth cohort study. Acta Paediatr 2007;96:1494e9.
16. National Health and Medical Research Council. Staying Healthy in Child Care: Preventing Infectious Diseases in Child Care. Canberra: NHMRC; 1994. 17. Bhutta ZA, Ali S, Cousens S, Ali TM, Haider BA, Rizvi A, Okong P, et al. Alma-Ata:
Rebirth and Revision 6 Interventions to address maternal, newborn, and child survival: what difference can integrated primary health care strategies make? Lancet 2008;372:972e89.
18. Bhutta ZA, Ahmed T, Black RE, Cousens S, Dewey K, Giugliani E, Haider BA, et al. What works? Interventions for maternal and child undernutrition and survival. Lancet 2008;371:417e40.
19. Barros AJ, Ross DA, Fonseca WV, Williams LA, Moreira-Filho DC. Preventing acute respiratory infections and diarrhoea in child care centres. Acta Paediatr 1999;88:1113e8.
20. Ejemot RI, Ehiri JE, Meremikwu MM, Critchley JA. Hand washing for preventing diarrhoea. Cochrane Database Syst Rev 2008;(1). CD004265.
21. Curtis V, Cairncross S. Effect of washing hands with soap on diarrhoea risk in the community: a systematic review. Lancet Infect Dis 2003;3:275e81. 22. Roberts L, Jorm L, Patel M, Smith W, Douglas RM, McGilchrist C. Effect of
infection control measures on the frequency of diarrheal episodes in child care: a randomized, controlled trial. Pediatrics 2000;105(4 Pt 1):743e6.
23. Gismondo MR, Drago L, Lombardi A. Review of probiotics available to modify gastrointestinalflora. Int J Antimicrob Agents 1999;12:287e92.
24. Sanders ME. Probiotics: definition, sources, selection, and uses. Clin Infect Dis 2008;46(Suppl 2):S58e61. discussion S144e51.
25. Lemberg DA, Chee YO, Day AS. Probiotics in paediatric gastrointestinal diseases. J Paediatr Child Health 2007;43:331e6.
26. Sherman PM, Cabana M, Gibson GR, Koletzko BV, Neu J, Veereman-Wauters G, Ziegler EE, et al. Potential roles and clinical utility of prebiotics in newborns, infants, and children: proceedings from a global prebiotic summit meeting, New York City, June 27-28, 2008. J Pediatr 2009;155:S61e70.
27. Gibson GR, Beatty ER, Wang X, Cummings JH. Selective stimulation of bifido-bacteria in the human colon by oligofructose and inulin. Gastroenterology 1995;108:975e82.
28. Wang X, Gibson GR. Effects of the in vitro fermentation of oligofructose and inulin by bacteria growing in the human large intestine. J Appl Bacteriol 1993;75:373e80.
29. Turnbaugh PJ, Ley RE, Hamady M, Fraser-Liggett CM, Knight R, Gordon JI. The human microbiome project. Nature 2007;449:804e10.
30. Bengmark S. Ecological control of the gastrointestinal tract. The role of pro-bioticflora. Gut 1998;42:2e7.
31. Eckburg PB, Bik EM, Bernstein CN, Purdom E, Dethlefsen L, Sargent M, et al. Diversity of the human intestinal microbialflora. Science 2005;308:1635e8. 32. Preidis GA, Versalovic J. Targeting the human microbiome with antibiotics,
probiotics, and prebiotics: gastroenterology enters the metagenomics era. Gastroenterology 2009;136:2015e31.
33. Turnbaugh PJ, Hamady M, Yatsunenko T, Cantarel BL, Duncan A, Ley RE, Sogin ML, et al. A core gut microbiome in obese and lean twins. Nature 2009; 457:480e4.
34. Ley RE. Obesity and the human microbiome. Curr Opin Gastroenterol 2010;26:5e11.
35. Szajewska H, Kotowska M, Mrukowicz JZ, Armanska M, Mikolajczyk W. Efficacy of Lactobacillus GG in prevention of nosocomial diarrhea in infants. J Pediatr 2001;138:361e5.
36. Oberhelman RA, Gilman RH, Sheen P, Taylor DN, Black RE, Cabrera L, Lescano AG, et al. A placebo-controlled trial of Lactobacillus GG to prevent diarrhea in undernourished Peruvian children. J Pediatr 1999;134:15e20. 37. Lewis SJ, Freedman AR. Review article: the use of biotherapeutic agents in the
prevention and treatment of gastrointestinal disease. Aliment Pharmacol Ther 1998;12:807e22.
38. Sazawal S, Hiremath G, Dhingra U, Malik P, Deb S, Black RE. Efficacy of pro-biotics in prevention of acute diarrhoea: a meta-analysis of masked, rando-mised, placebo-controlled trials. Lancet Infect Dis 2006;6:374e82.
39. Minocha A. Probiotics for preventive health. Nutr Clin Pract 2009;24:227e41. 40. de Vrese M, Marteau PR. Probiotics and prebiotics: effects on diarrhea. J Nutr
2007;137(3 Suppl 2):803Se11.
41. DuPont HL, Ericsson CD, Farthing MJ, Gorbach S, Pickering LK, Rombo L, Steffen R, et al. Expert review of the evidence base for prevention of travelers’ diarrhea. J Travel Med 2009;16:149e60.
42. Thibault H, Aubert-Jacquin C, Goulet O. Effects of long-term consumption of a fermented infant formula (with Bifidobacterium breve c50 and Streptococcus thermophilus 065) on acute diarrhea in healthy infants. J Pediatr Gastroenterol Nutr 2004;39:147e52.
43. Binns CW, Lee AH, Harding H, Gracey M, Barclay DV. The CUPDAY Study: prebiotic-probiotic milk product in 1-3-year-old children attending childcare centres. Acta Paediatr 2007;96:1646e50.
44. Osborn DA, Sinn JK. Probiotics in infants for prevention of allergic disease and food hypersensitivity. Cochrane Database Syst Rev 2007;(4):CD006475. 45. Huertas-Ceballos AA, Logan S, Bennett C, Macarthur C. Dietary interventions for
recurrent abdominal pain (RAP) and irritable bowel syndrome (IBS) in child-hood. Cochrane Database Syst Rev 2009;(1):CD003019.
