Lactobacillus GG in the prevention of antibiotic-associated diarrhea in children

Saccharomyces cerevisiae fungemia after Saccharomyces boulardii treatment in immunocompromised patients

Saccharomyces cerevisiae is widely used as a probiotic compound. Clinical data suggest that this agent is safe and effective. We report two cases of fungemia caused by S. cerevisiae occurring in immunosuppressed patients treated orally with S. boulardii Molecular typing confirmed clonality in isolate strains from patients and the capsule. Physicians caring for immunosuppressed patients must be aware of this potential serious complication of probiotic use.

The bactericidal effects of Lactobacillus acidophilus, garcinol and Protykin compared to clarithromycin, on Helicobacter pylori

Chronic infection with Helicobacter pylori causes peptic ulcers, gastric cancer and lymphoma. We evaluated the inhibitory effects of the probiotic Lactobacillus acidophilus DDS-1J, the antibiotic clarithromycin and the natural antioxidants garcinol and Protykin (containing 50% trans-resveratrol) on Helicobacter pylori strain ATCC 49503. The findings of this study indicate that Lactobacillus acidophilus DDS-1J exerts a growth inhibitory effect on H. pylori at a ratio of 1:1 or higher in vitro. In the case of clarithromycin, garcinol and resveratrol, the bactericidal effect is time and concentration dependent. Clarithromycin completely inhibited growth at > or = 62.5 microg/ml at 6 h and at > or = 31.5 microg/ml at 12 h. For garcinol the highest concentration needed for complete inhibition was 31.5 microg/ml at 6 h and 3.9 microg/ml after 12 h incubation. For resveratrol, significant inhibition was noted at 1000 microg/ml at 12 h only. The bactericidal effect of garcinol was reduced by the addition of resveratrol at all concentrations < or = 125 microg/ml at 6 and 12 h. We conclude from this study that Lactobacillus acidophilus DDS-1J inhibits H. pylori at 1:1 and higher ratios. Also, between the two antioxidants, garcinol is much more potent than resveratrol as a bactericidal agent against H. pylori, and that resveratrol may antagonize this effect. Finally, our study showed equivalent or better bactericidal activity of garcinol compared to clarithromycin against H. pylori at 6 and 12 h incubation, indicating a potential role for this antioxidant in treatment for H. pylori infection.

Nutritional impact of pre- and probiotics as protective gastrointestinal organisms

The health benefits of pre- and probiotics have been the subject of increased research interests. These food supplements have been demonstrated to alter the pre-existing intestinal flora so as to provide an advantage to the host. This review focuses on the scientific evidence both for and against their role in promoting health and treating disease. Specific attention is turned to their effects on immunomodulation, lipid metabolism, cancer prevention, diarrhea, Helicobacter pylori, necrotizing enterocolitis, allergy, and inflammatory bowel disease.

Effect of different probiotic preparations on anti-helicobacter pylori therapy-related side effects: a parallel group, triple blind, placebo-controlled study

OBJECTIVES

Several studies show that probiotics may prevent side effects during therapy against Helicobacter pylori (H. pylori). Other reports indicate competitive interaction between some probiotics and H. pylori. We compared efficacy of two different probiotics and one probiotic combination with placebo for preventing anti-H. pylori therapy-related side effects and for improving the eradication rate.

METHODS

A total of 85 H. pylori positive, asymptomatic patients were randomized in four groups to receive probiotic or placebo both during and for 7 days after a 1-wk triple therapy scheme (rabeprazole 20 mg b.id., clarithromycin 500 mg b.i.d., and tinidazole 500 mg b.i.d.). Group I (n = 21) received Lactobacillus GG; group II (n = 22), Saccharomyces boulardii; group III (n = 21), a combination of Lactobacillus spp. and biphidobacteria; and group IV (n = 21), placebo. Subjects filled in weekly symptom questionnaires for 4 wk. Blinded investigators collected and analyzed data. H. pylori status was rechecked after 5-7 wk.

RESULTS

Side effects occurred mainly during the eradication week. None of them caused therapy discontinuation. In all probiotic-supplemented groups, there was a significantly lower incidence of diarrhea and taste disturbance during the eradication week with respect to the placebo group. Overall assessment of tolerability was significantly better in the actively treated patients than in the placebo group. No differences in the incidence of side effects between the probiotic groups were observed. The H. pylori eradication rate was almost identical between the probiotic and placebo groups.

CONCLUSIONS

All the probiotics used were superior to placebo for side effect prevention, but were not associated with better compliance with antibiotic therapy. The effect of probiotic supplementation on side effects during anti-H. pylori regimens seemed to be independent of the probiotic species used.

The immune system: a target for functional foods?

The immune system acts to protect the host from infectious agents that exist in the environment (bacteria, viruses, fungi, parasites) and from other noxious insults. The immune system is constantly active, acting to discriminate 'non-self' from 'self'. The immune system has two functional divisions: the innate and the acquired. Both components involve various blood-borne factors (complement, antibodies, cytokines) and cells. A number of methodologies exist to assess aspects of immune function; many of these rely upon studying cells in culture ex vivo. There are large inter-individual variations in many immune functions even among the healthy. Genetics, age, gender, smoking habits, habitual levels of exercise, alcohol consumption, diet, stage in the female menstrual cycle, stress, history of infections and vaccinations, and early life experiences are likely to be important contributors to the observed variation. While it is clear that individuals with immune responses significantly below 'normal' are more susceptible to infectious agents and exhibit increased infectious morbidity and mortality, it is not clear how the variation in immune function among healthy individuals relates to variation in susceptibility to infection. Nutrient status is an important factor contributing to immune competence: undernutrition impairs the immune system, suppressing immune functions that are fundamental to host protection. Undernutrition leading to impairment of immune function can be due to insufficient intake of energy and macronutrients and/or due to deficiencies in specific micronutrients. Often these occur in combination. Nutrients that have been demonstrated (in either animal or human studies) to be required for the immune system to function efficiently include essential amino acids, the essential fatty acid linoleic acid, vitamin A, folic acid, vitamin B6, vitamin B12, vitamin C, vitamin E, Zn, Cu, Fe and Se. Practically all forms of immunity may be affected by deficiencies in one or more of these nutrients. Animal and human studies have demonstrated that adding the deficient nutrient back to the diet can restore immune function and resistance to infection. Among the nutrients studied most in this regard are vitamin E and Zn. Increasing intakes of some nutrients above habitual and recommended levels can enhance some aspects of immune function. However, excess amounts of some nutrients also impair immune function. There is increasing evidence that probiotic bacteria improve host immune function. The effect of enhancing immune function on host resistance to infection in healthy individuals is not clear.

The place of probiotics in human intestinal infections

A number of studies have been carried out on the effect of several probiotic species on treatment and prevention of intestinal infections. The most commonly used microorganisms are lactic-acid producing bacteria such as lactobacilli and bifidobacteria belonging to the human normal microflora. In vitro and animal studies have shown that probiotic microorganisms interfere with the colonisation of Helicobacter pylori and of enteropathogenic microorganisms. In humans the significance is more uncertain. Clinically significant benefits of probiotics have been demonstrated in the treatment of rotavirus induced diarrhoea and of Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea (AAD). In patients suffering from inflammatory bowel disease, several probiotic strains have been shown to be as effective as traditional medication in preventing relapses. Standardised and well performed studies are needed to elucidate further the mechanisms of action and the clinical significance of probiotics.

Pouchitis in Children: Therapeutic Options

Pouchitis is an unfortunate common complication of the ileal pouch-anal anastomosis procedure, an otherwise very attractive surgical option in patients with ulcerative colitis (UC). The fact that the same pouch in familial polyposis is hardly complicated by pouchitis suggests that the basic inflammatory process in UC might participate in the pathophysiology. We review the clinical features of pouchitis, the diagnostic approach, and the many therapeutic considerations, including more recent data on prebiotics and probiotics.

Lactobacillus plantarum reduces the in vitro secretory response of intestinal epithelial cells to enteropathogenic Escherichia coli infection

OBJECTIVE

Enteropathogenic (EPEC) is a Gram-negative bacillus that causes diarrhea. Secretory responses of intestinal epithelial cells can be seen after EPEC infection. Probiotics, which are live bacteria that have proven benefit to the host, play a role in the treatment and prevention of the different enteric pathogens. The goals of the study were to determine whether the probiotic agent (LBP) strain 299v alters the secretory changes seen in EPEC infection and, if so, what underlying mechanism is possible.

METHODS

Caco-2 cell monolayers were rapidly infected with EPEC strain E2348/69 and immediately mounted in Ussing chambers. The monolayers were exposed to LBP before, after, and simultaneously with EPEC infection. Short circuit current (Isc) was measured in the Ussing chamber.

RESULTS

EPEC infection caused an increase in short circuit current that was reduced by preincubation with LBP ( < 0.01). No direct bactericidal effect was observed, but LBP reduced the attachment of EPEC to Caco-2 cells.

CONCLUSION

LBP can play an important role in reducing the secretory change in response to EPEC infection, possibly through inhibition of its binding. However, the presence of the probiotic agent before the infection is necessary. In this setting, its role is more preventive rather than therapeutic.

Probiotics and intestinal health effects: a clinical perspective

Probiotics are viable non-pathogenic micro-organisms which, when ingested, exert a positive influence on host health or physiology. We have critically analysed the evidence for the efficacy of specific probiotic strains in human gastrointestinal diseases. The best evidence can be obtained with randomised controlled trials which avoid bias. Good evidence has been obtained with several strains in the prevention or treatment of antibiotic-associated disorders, in the treatment (and to a lesser extent prevention) of gastroenteritis and acute diarrhoea and in the alleviation of lactose intolerance. We also analysed the recent randomised controlled trials performed in patients with Clostridium difficile or Helicobacter pylori, inflammatory bowel disease, irritable bowel syndrome, non-ulcer dyspepsia and colon cancer.

Probiotics in the third millennium

Probiotics are "living microorganisms which upon ingestion in certain numbers exert health benefits beyond inherent general nutrition". Since 1987, when the first publication on the properties of the Lactobacillus GG was done, overall, there have been over 200 publications in peer-reviewed scientific journals. This paper will report the status and the prospectus of probiotics research at the beginning of the Third Millennium. Probiotics have proven benefits in treatment and prevention of rotavirus diarrhoea in children and reduction of antibiotic-associated intestinal side-effects. Interesting results have recently been published regarding food allergies and atopic eczema in children. Prevention of vaginitis and of travellers' diarrhoea have also been reported. Promising results are being reported in patients with inflammatory bowel disease, cystic fibrosis, dental caries and irritable bowel syndrome. It has also been suggested that probiotics could enhance oral vaccine administration, and that they may help treatment against Helicobacter pylori infection, but further studies are needed. Future areas of research regard probiotics' role in the process of carcinogenesis, given their influence on the gut microflora, and as immune modulators in autoimmune disorders. The possibility of introducing appropriate genes to the probiotics to make them produce various compounds is also under investigation. However, there is still confusion in the minds of the authorities over whether a probiotic is a drug, a food, or a dietary supplement. The challenge is to continue research to define the appropriate uses of probiotics and discover new applications which will bring benefit to humankind.

Meta-analysis: the effect of probiotic administration on antibiotic-associated diarrhoea

BACKGROUND

Antibiotic-associated diarrhoea can be attributed in part to imbalances in intestinal microflora. Therefore, probiotic preparations are used to prevent this diarrhoea. However, although several trials have been conducted, no conclusive evidence has been found of the efficacy of different preparations, e.g. Lactobacillus spp. and Saccharomyces spp.

AIM

To conduct a meta-analysis of the data in the literature on the efficacy of probiotics in the prevention of antibiotic-associated diarrhoea.

METHODS

A literature search was performed of electronic databases, Abstract Books and single paper references. Data were also obtained from the authors. Only placebo-controlled studies were included in the search. The Mantel-Haenszel test was used to estimate the relative risk for single studies and an overall combined relative risk, each study being submitted to the Mantel-Haenszel test for homogeneity.

RESULTS

Twenty-two studies matched the inclusion criteria. Only seven studies (881 patients) were homogeneous. The combined relative risk was 0.3966 (95% confidence interval, 0.27-0.57).

CONCLUSIONS

The results suggest a strong benefit of probiotic administration on antibiotic-associated diarrhoea, but further data are needed. The evidence for beneficial effects is still not definitive. Published studies are flawed by the lack of a placebo design and by peculiar population features.

Human studies with probiotics and prebiotics: clinical implications

Probiotic agents have been shown to have significant clinical beneficial effects in the prevention and management of gastrointestinal and non-gastrointestinal conditions. These observations have led to work demonstrating that an important mechanism of these agents is their close interaction with the gut associated lymphoid tissue (GALT) and suggested immunomodulatory effects on systemic immune response. Studies on the possibility that prebiotic agents might directly or indirectly induce similar immunomodulation have only recently begun. The preliminary findings of several recent human clinical trials reviewed in this article indicate that prebiotics may indeed prove to be a clinically beneficial dietary supplement, in the context of novel nutritional strategies for the management of gastrointestinal and systemic conditions.

In situ delivery of passive immunity by lactobacilli producing single-chain antibodies

Lactobacilli have previously been used to deliver vaccine components for active immunization in vivo. Vectors encoding a single-chain Fv (scFv) antibody fragment, which recognizes the streptococcal antigen I/II (SAI/II) adhesion molecule of Streptococcus mutans, were constructed and expressed in Lactobacillus zeae (American Type Culture Collection (ATCC) 393). The scFv antibody fragments secreted into the supernatant or expressed on the surface of the bacteria showed binding activity against SAI/II in enzyme-linked immunosorbent assay (ELISA), and surface scFv-expressing lactobacilli agglutinated SAI/II-expressing S. mutans in vitro without affecting the corresponding SAI/II knockout strain. Lactobacilli expressing the scFv fragment fused to an E-tag were visualized by scanning electron microscopy (SEM) using beads coated with a monoclonal anti-E-tag antibody, and they bound directly to beads coated with SAI/II. After administration of scFv-expressing bacteria to a rat model of dental caries development, S. mutans bacteria counts and caries scores were markedly reduced. As lactobacilli are generally regarded as safe (GRAS) microorganisms, this approach may be of considerable commercial interest for in vivo immunotherapy.

Probiotics in prevention of antibiotic associated diarrhoea: meta-analysis

OBJECTIVE

To evaluate efficacy of probiotics in prevention and treatment of diarrhoea associated with the use of antibiotics.

DESIGN

Meta-analysis; outcome data (proportion of patients not getting diarrhoea) were analysed, pooled, and compared to determine odds ratios in treated and control groups.

IDENTIFICATION

Studies identified by searching Medline between 1966 and 2000 and the Cochrane Library. Studies reviewed Nine randomised, double blind, placebo controlled trials of probiotics.

RESULTS

Two of the nine studies investigated the effects of probiotics in children. Four trials used a yeast (Saccharomyces boulardii), four used lactobacilli, and one used a strain of enterococcus that produced lactic acid. Three trials used a combination of probiotic strains of bacteria. In all nine trials, the probiotics were given in combination with antibiotics and the control groups received placebo and antibiotics. The odds ratio in favour of active treatment over placebo in preventing diarrhoea associated with antibiotics was 0.39 (95% confidence interval 0.25 to 0.62; P<0.001) for the yeast and 0.34 (0.19 to 0.61; P<0.01 for lactobacilli. The combined odds ratio was 0.37 (0.26 to 0.53; P<0.001) in favour of active treatment over placebo.

CONCLUSIONS

The meta-analysis suggests that probiotics can be used to prevent antibiotic associated diarrhoea and that S boulardii and lactobacilli have the potential to be used in this situation. The efficacy of probiotics in treating antibiotic associated diarrhoea remains to be proved. A further large trial in which probiotics are used as preventive agents should look at the costs of and need for routine use of these agents.

Probiotics in clinical conditions

Probiotics are nonpathogenic microorganisms which, when ingested, exert a positive influence on the health or physiology of the host. Their mechanisms of action and effects are now studied using the same pharmacological approach as for drugs. This article summarizes and comments on evidence for the positive effects of probiotics in various clinical situations. Substantial evidence can be achieved when randomized controlled trials or meta-analyses show positive results. The clinical situations studied include prevention or treatment of antibiotic-associated disorders, gastroenteritis, and diarrhea, lactose intolerance, intestinal infections and colonization by pathogenic bacteria (including Helicobacter pylori and Clostridium difficile), traveler's diarrhea, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), colonic cancer, urogenital infections and tumors, allergy (especially atopic eczema), vaccination, and cholesterol lowering. Current probiotics have an excellent safety record--another topic discussed in this article.

Probiotic supplementation reduces the risk of bacterial translocation in experimental short bowel syndrome

BACKGROUND/PURPOSE

Probiotics are live organisms that survive passage through the gastrointestinal tract and have beneficial effects on the host. Lactobacillus and Bifidobacterium have been recommended for cholesterol lowering, acute diarrhea, prevention of cancer, or inflammatory bowel disease. On the other hand, after massive bowel resection, bacterial overgrowth is frequent and favors bacterial translocation (BT). The possible beneficial effects of Bifidobacterium lactis (BL) administration on BT in experimental short bowel syndrome (SBS), have not been investigated. The aim of this study was to test the hypothesis that BL administration decreases BT in SBS in animals fed orally.

METHODS

One hundred twenty-eight adult Wistar rats fed orally with standard rat chow and tap water "ad libitum" were maintained in individual metabolic cages for 10 days and divided into 3 groups: control group (n = 71): nonmanipulated animals; RES group (n = 39): 80% gut resection from 10 cm beyond the angle of Treitz to 10 cm above the cecum; RES-PRO group (n = 18): same resection and daily 7.8 x 10(8) CFU B Lactis administration, after orogastric intubation. At the end of the experiment they were killed, and mesenteric lymph nodes (MLN) and peripheral and portal blood specimens were recovered and cultured. Bacterial identification in blood was made by conventional methods, and MLN culture was considered positive with a growth over 100 CFU/g.

RESULTS

Bacterial translocation was detected in 6% of control group rats. The incidence of BT in the RES group was 87% (34 of 39), whereas only 50% (9 of 18) of RES-PRO animals had BT (P <.05). The relative risk reduction (RRR) was 0.43 (95% Cl 0.14 to 0.72), and the number needed to treat (NNT) was 3 (95% Cl 2 to 8). In other words, animals that received BL had the risk of BT reduced by 43% (RRR of 0.43), and of every 3 animals treated, 1 is expected to be free of BT (NNT of 3).

CONCLUSION

Administration of B Lactis reduces the incidence of BT in adult Wistar rats after 80% gut resection.

Protective nutrients and functional foods for the gastrointestinal tract

Epithelial and other cells of the gastrointestinal mucosa rely on both luminal and bloodstream sources for their nutrition. The term functional food is used to describe nutrients that have an effect on physiologic processes that is separate from their established nutritional function, and some of these nutrients are proposed to promote gastrointestinal mucosal integrity. We review the recent in vitro, animal, and clinical experiments that evaluated the role of several types of gastrointestinal functional foods, including the amino acids glutamine and arginine, the essential micronutrients vitamin A and zinc, and 2 classes of food additives, prebiotics and probiotics. Many of the data from preclinical studies support a strong role for enteral nutrients in gastrointestinal health; in comparison, the data from human studies are limited. In some cases, impressive data from in vitro and animal studies have not been replicated in human trials. Other clinical trials have shown positive health benefits, but some of those studies were plagued by flaws in study design or analysis. The methods available to detect important changes in human gastrointestinal function and structure are still limited, but with the development of more sensitive measures of gastrointestinal function, the effects of specific nutrients may be more easily detected. This may facilitate the development of phase 3 clinical trials designed to more rigorously evaluate the effects of a particular nutrient by focusing on valid and reliable outcome measures. Regulatory changes in the way in which health claims can be made for dietary supplements should also be encouraged.

Probiotics and prebiotics: A brief overview

Probiotics and prebiotics are 2 food ingredients that confer physiologic effects through the gastrointestinal tract. Probiotics have been defined as viable microorganisms that (when ingested) have a beneficial effect in the prevention and treatment of specific pathologic conditions. These microorganisms are believed to exert biological effects through a phenomenon known as colonization resistance, whereby the indigenous anaerobic flora limits the concentration of potentially pathogenic (mostly aerobic) flora in the digestive tract. Other modes of action, such as supplying enzymes or influencing enzyme activity in the gastrointestinal tract, may also account for some of the other physiologic effects that have been attributed to probiotics. Conversely, prebiotics are nondigestible food ingredients that beneficially affect host health by selectively stimulating the growth and/or activity of 1 or a limited number of bacteria in the colon. The prebiotic, fructooligosaccharide (FOS), is found naturally in many foods, such as wheat, onions, bananas, honey, garlic, or leeks. They can also be isolated from chicory root or synthesized enzymatically from sucrose. Fermentation of FOS in the colon results in a large number of physiologic effects including increasing the numbers of bifidobacteria in the colon, increasing calcium absorption, increasing fecal weight, shortening of gastrointestinal transit time, and possibly lowering blood lipid levels. Other effects that have been observed in animal models include an increase in cecal weight and an increase in fecal nitrogen excretion. The increase in bifidobacteria has been assumed to benefit human health by producing compounds to inhibit potential pathogens, by reducing blood ammonia levels, and by producing vitamins and digestive enzymes.

Gut microbial ecology in critical illness: is there a role for prebiotics, probiotics, and synbiotics?

Approximately 70% of the immune system is localized in the gastrointestinal tract: its glands, mucosa, and mucosa-associated lymphoid system. The system influences health conditions because it produces large amounts of important gastrointestinal secretions as rich as breast milk in health-supporting and disease-preventing factors, and because of its rich gastrointestinal flora. The intestine normally contains 10 times more microbes than there are eukaryotic cells in the entire body. The optimal function of these microbes depends on the supply of food destined for the colonic bacteria (fermentable fibers, complex proteins, gastrointestinal secretions). The consideration of these functions influences outcome. Unfortunately, the conditions (supply of drugs-especially antibiotics, and reduced supply of food-especially fruits and vegetables) in the modern ICU are extremely poor both for optimal gastrointestinal secretion and for flora and need more attention. To improve treatment, a supply of new and effective flora (probiotics) and food for the flora (prebiotics) is needed, from which numerous health-supporting products (synbiotics) will be produced and absorbed at the level of the mucosa, mainly in the lower gastrointestinal tract.

Lactobacillus therapy for acute infectious diarrhea in children: a meta-analysis

OBJECTIVE

Childhood diarrhea accounts for substantial morbidity and mortality worldwide. Multiple studies in children have shown that Lactobacillus, administered orally, may have antidiarrheal properties. We conducted a meta-analysis of randomized, controlled studies to assess whether treatment with Lactobacillus improves clinical outcomes in children with acute infectious diarrhea.

METHODS

Studies were sought in bibliographic databases of traditional biomedical as well as complementary and alternative medicine literature published from 1966 to 2000. Search terms were "competitive inhibition," "diarrhea," "gastroenteritis," "Lactobacillus," "probiotic," "rotavirus," and "yog(h)urt." We included studies that were adequately randomized, blinded, controlled trials in which the treatment group received Lactobacillus and the control group received an adequate placebo and that reported clinical outcome measures of diarrhea intensity. These inclusion criteria were applied by blind review and consensus. The original search yielded 26 studies, 9 of which met the criteria. Multiple observers independently extracted study characteristics and clinical outcomes. Data sufficient to perform meta-analysis of the effect of Lactobacillus on diarrhea duration and diarrhea frequency on day 2 were contained in 7 and 3 of the included studies, respectively.

RESULTS

Summary point estimates indicate a reduction in diarrhea duration of 0.7 days (95% confidence interval: 0.3-1.2 days) and a reduction in diarrhea frequency of 1.6 stools on day 2 of treatment (95% confidence interval: 0.7-2.6 fewer stools) in the participants who received Lactobacillus compared with those who received placebo. Details of treatment protocols varied among the studies. A preplanned subanalysis suggests a dose-effect relationship.

CONCLUSION

The results of this meta-analysis suggest that Lactobacillus is safe and effective as a treatment for children with acute infectious diarrhea.

Microbiologic evaluation of commercial probiotics

OBJECTIVE

To evaluate contents of commercial probiotic products marketed for veterinary or human administration.

DESIGN

Microbiologic culture assay.

SAMPLE POPULATION

8 veterinary probiotics and 5 human probiotics.

PROCEDURE

Quantitative bacteriologic culture was performed on all products, and isolates were identified via biochemical characteristics. Comparison of actual contents versus label claims was performed.

RESULTS

Label descriptions of organisms and concentrations accurately described the actual contents of only 2 of 13 products. Five veterinary products did not specifically list their contents. Most products contained low concentrations of viable organisms. Five products did not contain 1 or more of the stated organisms, and 3 products contained additional species. Some products contained organisms with no reported probiotic effects; some of these organisms could be pathogens.

CONCLUSIONS AND CLINICAL RELEVANCE

Most commercial veterinary probiotic preparations are not accurately represented by label claims. Quality control appears to be poor for commercial veterinary probiotics.

Probiotics in gastroenterology

Recent evidence has suggested the potential therapeutic role for probiotics in the prevention or treatment of gastrointestinal diseases. Several studies have shown that probiotics are of benefit in gastrointestinal infections, including viral diarrhea, Clostridium difficile-associated diarrhea, traveler's diarrhea, and antibiotic-associated diarrhea. Recent data support the potential beneficial therapeutic effect in inflammatory bowel disease as well. Other possible indications for probiotic treatment include Helicobacter pylori infection, irritable bowel syndrome, and radiotherapy-associated diarrhea. It is important to select well-characterized preparations; in fact, the viability and survival of many available preparations are unproven. More precise information on the mechanisms by which probiotic strains exert their beneficial effects in vivo is needed. This may provide the scientific rationale for the selection of the best probiotic strains to use in the performance of large, double-blind, controlled clinical trials.

Probiotics in health and disease in the pediatric patient

Probiotics are truly a timeless concept. Initially standard components of the human diet, potentially beneficial bacteria and yeast have been eliminated systematically through modern methods of preparing and preserving foods. Although the concept of probiotics is not new, the science of probiotics is in its infancy. Only recently have techniques been developed to identify, culture, and produce the probiotics that are suitable for medical use consistently. Furthermore, the potential uses for these organisms may extend far beyond what originally was thought. In no way should probiotics be thought of as a panacea for the diseases described earlier; however, when used appropriately, they represent a potentially beneficial adjunct to other proved therapies and have the added benefit of providing a stabilizing influence on the delicate balance between the ecosystem that consists of the human and its flora.

Pre-, pro- and synbiotics

Approximately 70% of the immune system is localized in the gastrointestinal tract. The saliva and gastrointestinal secretions, as well as flora (probiotics) and supplied fibres (prebiotics), are important for optimal function. Probiotic bacteria have been shown to influence the immune system through several molecular mechanisms. Pre-, pro- and synbiotics (products produced by fermentation) offer both protection against and cure of a variety of endemic and acute diseases. This review summarizes the present experience in various forms of diarrhoea, inflammatory bowel disease, and Helicobacter infections, in intensive care patients and in connection with extensive surgery.

Randomized clinical trial of soy formula with and without added fiber in antibiotic-induced diarrhea

OBJECTIVE

The objective of this study was to examine the effects of soy formulas with and without added soy fiber in children who developed diarrhea while receiving antibiotics.

DESIGN

In a masked, randomized parallel study, older infants and toddlers were fed commercial soy formulas with or without added soy fiber for 10 days on occurrence of diarrhea during the administration of antibiotics. Subjects were stratified by feeding (formula versus cow's milk). The primary variables were duration of diarrhea, stool characteristics, and intake. Secondary variables were weight and spit-up.

RESULTS

All 45 children who completed the 10-day study received >30% of their caloric intake from formula. Fiber intake from other foods did not differ between groups and averaged 0.5 g/day. Total median fiber intake of the group fed the formula with added fiber was 6.53 g/day. The mean duration of diarrhea was 25.1 +/- 5.2 hours for children fed the formula with added fiber and 51.6 +/- 10.7 hours for those fed the regular formula (P =.0013).

CONCLUSION

The duration of antibiotic-induced diarrhea in children fed the soy formula with added soy fiber was significantly reduced.

Food processing: probiotic microorganisms for beneficial foods

Human studies have demonstrated that selected probiotic strains can influence the composition of the intestinal microflora and modulate the host immune system. Considerable promise was also demonstrated for the application of probiotics in human disease. However, the extension of probiotic applications demands increasing scientific attention to their functionality and the identification of molecular structures.

Probiotic bacteria enhance murine and human intestinal epithelial barrier function

BACKGROUND & AIMS

The probiotic compound, VSL#3, is efficacious as maintenance therapy in pouchitis and ulcerative colitis. The aim of this study was to determine the efficacy of VSL#3 as a primary therapy in the treatment of colitis in the interleukin (IL)-10 gene-deficient mouse. Mechanisms of action of VSL#3 were investigated in T(84) monolayers.

METHODS

IL-10 gene-deficient and control mice received 2.8 x 10(8) colony-forming units per day of VSL#3 for 4 weeks. Colons were removed and analyzed for cytokine production, epithelial barrier function, and inflammation. VSL#3 or conditioned media was applied directly to T(84) monolayers.

RESULTS

Treatment of IL-10 gene-deficient mice with VSL#3 resulted in normalization of colonic physiologic function and barrier integrity in conjunction with a reduction in mucosal secretion of tumor necrosis factor alpha and interferon gamma and an improvement in histologic disease. In vitro studies showed that epithelial barrier function and resistance to Salmonella invasion could be enhanced by exposure to a proteinaceous soluble factor secreted by the bacteria found in the VSL#3 compound.

CONCLUSIONS

Oral administration of VSL#3 was effective as primary therapy in IL-10 gene-deficient mice, and had a direct effect on epithelial barrier function.

Biotherapeutic agents in the treatment of infectious diarrhea

Biotherapeutic agents offer unique advantages over traditional treatments for infectious diarrhea, and several have been shown to be effective (Table 4). These therapeutic microbial agents are most effective in types of infectious diseases that are associated with a disruption of the normal intestinal microecology (e.g., AAD, C. difficile disease). The impact of biotherapeutic agents on rotaviral diarrhea is of special clinical importance because this is the most common cause of pediatric diarrhea, and there is no defined treatment. Strong efforts need to be made to limit antibiotic exposure in children. Biotherapeutic agents offer a safe and effective nonantibiotic method of treating this important pathogen, especially after the withdrawal of a rotaviral vaccine from the market by the FDA. However, for many biotherapeutic agents, well-done, placebo-controlled trials still are lacking, and not all types of infectious diarrhea respond to these agents. Continued research in this innovative therapeutic area is warranted.

Lack of effect of Lactobacillus GG on antibiotic-associated diarrhea: a randomized, placebo-controlled trial

OBJECTIVES

To assess the efficacy of Lactobacillus GG in preventing antibiotic-associated diarrhea (AAD) in adults and, secondarily, to assess the effect of coadministered Lactobacillus GG on the number of tests performed to determine the cause of diarrhea.

PATIENTS AND METHODS

In this prospective, randomized, double-blind, placebo-controlled trial conducted from July 1998 to October 1999, 302 hospitalized patients receiving antibiotics were randomized to receive Lactobacillus GG, 20 x 10(9) CFU/d, or placebo for 14 days. Subjects recorded the number of stools and their consistency daily for 21 days. The primary outcome was the proportion of patients who developed diarrhea in the first 21 days after enrollment. Weekly telephone follow-up was also performed. Results were analyzed in an intention-to-treat fashion.

RESULTS

Diarrhea developed in 39 (29.3%) of 133 patients randomized to receive Lactobacillus GG and in 40 (29.9%) of 134 patients randomized to receive placebo (P=.93). No additional difference in the rate of occurrence of diarrhea was found between treatment and placebo patients in a subgroup analysis of those treated with beta-lactam vs non-beta-lactam antibiotics. Too few patients had stool cultures, additional laboratory tests for diarrhea, or a positive diagnosis of Clostridium difficile infection to assess between-group differences.

CONCLUSION

Lactobacillus GG in a dose of 20 x 10(9) CFU/d did not reduce the rate of occurrence of diarrhea in this sample of 267 adult patients taking antibiotics initially administered in the hospital setting.

Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomised trial

OBJECTIVE

To examine whether long term consumption of a probiotic milk could reduce gastrointestinal and respiratory infections in children in day care centres.

DESIGN

Randomised, double blind, placebo controlled study over seven months.

SETTING

18 day care centres in Helsinki, Finland.

PARTICIPANTS

571 healthy children aged 1-6 years: 282 (mean (SD) age 4.6 (1.5) years) in the intervention group and 289 (mean (SD) age 4.4 (1.5) years) in the control group.

INTERVENTION

Milk with or without Lactobacillus GG. Average daily consumption of milk in both groups was 260 ml.

MAIN OUTCOME MEASURES

Number of days with respiratory and gastrointestinal symptoms, absences from day care because of illness, respiratory tract infections diagnosed by a doctor, and course of antibiotics.

RESULTS

Children in the Lactobacillus group had fewer days of absence from day care because of illness (4.9 (95% confidence interval 4.4 to 5.5) v 5.8 (5.3 to 6.4) days, 16% difference, P=0.03; age adjusted 5.1 (4.6 to 5.6) v 5.7 (5.2 to 6.3) days, 11% difference, P=0.09). There was also a relative reduction of 17% in the number of children suffering from respiratory infections with complications and lower respiratory tract infections (unadjusted absolute % reduction -8.6 (-17.2 to -0.1), P=0.05; age adjusted odds ratio 0.75 (0.52 to 1.09), P=0.13) and a 19% relative reduction in antibiotic treatments for respiratory infection (unadjusted absolute % reduction -9.6 (-18.2 to -1.0), P=0.03; adjusted odds ratio 0.72 (0.50 to 1.03), P=0.08) in the Lactobacillus group.

CONCLUSIONS

Lactobacillus GG may reduce respiratory infections and their severity among children in day care. The effects of the probiotic Lactobacillus GG were modest but consistently in the same direction.

Clinical applications of probiotic agents

In the past century the beneficial roles of nonpathogenic bacteria in the intestinal lumen were described. In the past decade there has been a dramatic increase in scientific work supporting the concept that there are clinical benefits to ingesting specific nonpathogenic organisms (probiotics). The potential benefits of modifying the intestinal flora composition of certain high-risk groups, eg, premature infants, travelers, and children receiving antibiotics, are emerging in the literature. Studies documenting prophylactic and therapeutic benefits in acute viral gastroenteritis and in atopic disease point not only to the potential applications, but also to the fact that the mechanisms of action of these agents may be due to their interaction with the gut as an immunologic organ. The benefits documented thus far are of varying degree and are most likely dependent on the number of agents, the dose, the dosing patterns, and the characteristics of the host and its underlying luminal microbial environment. Consequently, the safety and specification of a particular probiotic agent and methods of delivery to a particular population for a particular purpose should be carefully documented before making broad recommendations. The cost-benefit assessment of adding probiotics to our diet for prophylactic or therapeutic purposes, as well as better regulation of these agents as commercial products, is also needed.

Probiotic agents and infectious diseases: a modern perspective on a traditional therapy

There is an increasing scientific and commercial interest in the use of beneficial microorganisms, or "probiotics," for the prevention and treatment of disease. The microorganisms most frequently used as probiotic agents are lactic-acid bacteria such as Lactobacillus rhamnosus GG (LGG), which has been extensively studied in recent literature. Multiple mechanisms of action have been postulated, including lactose digestion, production of antimicrobial agents, competition for space or nutrients, and immunomodulation. We have reviewed recent studies of probiotics for the treatment and control of infectious diseases. Studies of pediatric diarrhea show substantial evidence of clinical benefits from probiotic therapy in patients with viral gastroenteritis, and data on LGG treatment for Clostridium difficile diarrhea appear promising. However, data to support use of probiotics for prevention of traveler's diarrhea are more limited. New research suggests potential applications in vaccine development and prevention of sexually transmitted diseases. Further studies are needed to take full advantage of this traditional medical approach and to apply it to the infectious diseases of the new millennium.

Probiotics: future directions

Clinical studies have shown that certain probiotics may be useful in treating a variety of diarrheal disorders, including rotavirus diarrhea, antibiotic-associated diarrhea, Clostridium difficile diarrhea, and traveler's diarrhea. New data suggest that probiotics might be useful in controlling inflammatory diseases, treating and preventing allergic diseases, preventing cancer, and stimulating the immune system, which may reduce the incidence of respiratory disease. Different modes of administering probiotics are currently being investigated, which may ultimately lead to the widespread use of probiotics in functional foods. It is important that such practices be directed by carefully controlled clinical studies published in peer-reviewed journals.

Screening of intestinal microflora for effective probiotic bacteria

Increasing consumer awareness of health-promoting intestinal bacteria has fueled the addition of viable probiotic bacteria as functional ingredients in certain foods. However, to effectively market the enhanced attributes of these foods, the added probiotic bacteria need to have scientific credibility. The scientific rationale for using many of the strains of probiotic bacteria currently on the market is weak. Furthering the current understanding of what features a bacterium needs to have for effective probiotic functionality will enable the selection of strains with a more credible scientific rationale. To screen for effective strains, one must understand the microbial diversity in the intestines of healthy individuals. The advent of molecular tools has greatly enhanced our ability to accomplish this. These tools comprise genetic fingerprinting, specific probes, molecular speciation, and techniques for the in situ analysis of specific microbial groups in the intestine. This review will detail these scientific approaches and how their impact will improve criteria for selection of probiotic bacteria.

Bacteremic infection with Pediococcus: vancomycin-resistant opportunist

Pediococci are recently recognized Gram-positive human pathogens, resistant to vancomycin and generally susceptible to penicillin. Infection in adults has been seen in patients with chronic underlying conditions as well as those with previous abdominal surgery. Two previous infants with congenital gastrointestinal malformations requiring surgical correction have been reported with sepsis attributable to Pediococcus sp. We report a third infant born with gastroschisis who developed Pediococcus bacteremia and meningitis 3 months after surgery, and speculate regarding the role of probiotics in the pathogenesis of this infection.

Efficacy of Lactobacillus GG in prevention of nosocomial diarrhea in infants

OBJECTIVE

Nosocomial diarrhea is a major problem in pediatric hospitals worldwide. We evaluated the efficacy of orally administered Lactobacillus GG (LGG) in the prevention of this disease in young children.

STUDY DESIGN

Eighty-one children aged 1 to 36 months who were hospitalized for reasons other than diarrhea were enrolled in a double-blind trial and randomly assigned at admission to receive LGG (n = 45) at a dose of 6 x 10(9) colony-forming units or a comparable placebo (n = 36) twice daily orally for the duration of their hospital stay.

RESULTS

LGG reduced the risk of nosocomial diarrhea (> or =3 loose or watery stools/24 h) in comparison with placebo (6.7% vs 33.3%; relative risk: 0.2; [95% CI: 0.06-0.6]; number needed to treat: 4 [95% CI: 2-10]). The prevalence of rotavirus infection was similar in LGG and placebo groups (20% vs 27.8%, respectively; relative risk: 0.72; 95% CI: 0.33-1.56). However, the use of LGG compared with placebo significantly reduced the risk of rotavirus gastroenteritis (1/45 [2.2%] vs 6/36 [16.7%], respectively; relative risk: 0.13; 95% CI: 0.02-0.79; number needed to treat: 7; 95% CI: 3-40).

CONCLUSIONS

Prophylactic use of LGG significantly reduced the risk of nosocomial diarrhea in infants, particularly nosocomial rotavirus gastroenteritis.

The effect of oral administration of Lactobacillus GG on antibiotic-associated gastrointestinal side-effects during Helicobacter pylori eradication therapy

BACKGROUND

One-week triple therapy is currently considered the golden standard against Helicobacter pylori. However, gastrointestinal side-effects are among the major pitfalls in such regimens. Probiotic supplementation might help to prevent or reduce such drug-related manifestations.

AIM

To determine whether adding the probiotic Lactobacillus GG to an anti-H. pylori regimen could help to prevent or minimize the gastrointestinal side-effects burden.

METHODS

Sixty healthy asymptomatic subjects screened positive for H. pylori infection were randomized to 1 week rabeprazole (20 mg b.d.), clarithromycin (500 mg b.d.), tinidazole (500 b.d.) and the probiotic Lactobacillus GG for 14 days or to the same regimen with a placebo preparation. Patients completed validated questionnaires during the week of treatment and during the following 3 weeks, to determine the type and severity of side-effects and an overall judgement of tolerability.

RESULTS

Diarrhoea, nausea and taste disturbance were significantly reduced in the Lactobacillus GG supplemented group (relative risk=0.1, 95% CI: 0.1-0.9; relative risk=0.3, 95% CI: 0.1-0.9; relative risk=0.5, 95% CI: 0.2-0.9, respectively). An overall assessment of treatment tolerability showed a significant difference in favour of the Lactobacillus GG supplemented group (P=0.04).

CONCLUSIONS

Lactobacillus GG supplementation showed a positive impact on H. pylori therapy-related side-effects and on overall treatment tolerability.

The role of probiotics in the treatment of intestinal infections and inflammation

Clinical studies have established that certain probiotics are useful in a variety of intestinal disorders, including viral diarrhea, antibiotic-associated diarrhea, Clostridium difficile-associated diarrhea, and traveler's diarrhea. Evolving data suggest that probiotics might be useful in the control of inflammatory diseases, treatment and prevention of allergic diseases, cancer prevention, and stimulation of the immune system, which may result in the reduction in respiratory disease. A review of current data regarding the most common probiotics is presented. It is important that probiotic use be directed by well-designed, placebo-controlled clinical studies published in peer-reviewed journals.

Probiotics in pediatric gastrointestinal disorders

Probiotics have been defined most recently as living microorganisms which, upon ingestion in certain numbers, exact health benefits beyond inherent general nutrition. They have been a part of human nutrition for centuries, but in recent years they have been more closely studied for their potential to improve health and treat disease. This review of probiotics is not extensive, highlighting the most recent reviews and well controlled clinical studies in both animals and humans. The safety issues are also discussed as well as potential mechanisms of action. The importance of studying each probiotic bacterium individually in each condition where a health benefit is claimed is highlighted by Lactobacillus GG, the most widely studied probiotic which has proven benefit in reducing the severity and duration of viral diarrhea but no benefit against bacterial diarrhea.