Clinical applications of probiotic agents

Helicobacter pylori, microbiota and gastric cancer - principles of microorganism-driven carcinogenesis

The demonstration that Helicobacter pylori is a pathogenic bacterium with marked carcinogenic potential has paved the way for new preventive approaches for gastric cancer. Although decades of research have uncovered complex interactions of H. pylori with epithelial cells, current insights have refined our view on H. pylori-associated carcinogenesis. Specifically, the cell-type-specific effects on gastric stem and progenitor cells deep in gastric glands provide a new view on the ability of the bacteria to colonize long-term, manipulate host responses and promote gastric pathology. Furthermore, new, large-scale epidemiological data have shed light on factors that determine why only a subset of carriers progress to gastric cancer. Currently, technological advances have brought yet another revelation: H. pylori is far from the only microorganism able to colonize the stomach. Instead, the stomach is colonized by a diverse gastric microbiota, and there is emerging evidence for the occurrence and pathological effect of dysbiosis resulting from an aberrant interplay between H. pylori and the gastric mucosa. With the weight of this evidence mounting, here we consider how the lessons learned from H. pylori research inform and synergize with this emerging field to bring a more comprehensive understanding of the role of microbes in gastric carcinogenesis.

Human Breast Milk: The Role of Its Microbiota and Metabolites in Infant Health

This review explores the role of microorganisms and metabolites in human breast milk and their impact on neonatal health. Breast milk serves as both a primary source of nutrition for newborns and contributes to the development and maturation of the digestive, immunological, and neurological systems. It has the potential to reduce the risks of infections, allergies, and asthma. As our understanding of the properties of human milk advances, there is growing interest in incorporating its benefits into personalized infant nutrition strategies, particularly in situations in which breastfeeding is not an option. Future infant formula products are expected to emulate the composition and advantages of human milk, aligning with an evolving understanding of infant nutrition. The long-term health implications of human milk are still under investigation.

Investigation and comparison of the effects of two probiotic bacteria, and in reducing mutans streptococci levels in the saliva of children

Background

Probiotic organisms Lactobacillus reuteri UBLRU-87 and Bifidobacterium bifidum UBBB-55 were proven to be acting against the caries causing organisms.

Aims

This study aims to evaluate the influence of Lactobacillusreuteri, Bifidobacterium bifidum and their blend on Mutans streptococci count in the saliva of children, and also to appraise the sustainability of their action.

Materials and Methods

A randomized, double-blind and placebo-controlled study with 60 subjects (15 in each group) in 6-14 years of age group. The children consumed curd containing Bifidobacterium bifidum (UBBB 55, MTCC 5398) and Lactobacillus reuteri (UBLRu 87, MTCC 5403), and their blend once daily for 14 days. The control group received curd with no Probiotic in it. The saliva samples were collected just before the curd (T0) administration to establish baseline levels of mutans streptococci and after a day of the final consumption of the curd (T14). The follow-up samples at 21 days (T21) and 28 days (T28) after the baseline were also collected to know the sustainability of action probiotics on mutans streptococci if any.

Results

Statistically significant reduction of mutans streptococci is observed in the group administered with Lactobacillus reuteri and the effect lasted up to a minimum of 21 days. Mixed cultures are seemed to be not effective against the oral microorganisms.

Conclusions

The probiotic organism Lactobacillus reuteri in Indian curd is effective on salivary mutans streptococci, and the effect was sustained for some period after the administration.

Improving the Gut Microbiota with Probiotics and Faecal Microbiota Transplantation

Probiotics are “live strains of strictly selected microorganisms which, when administered in adequate amounts, confer a health benefit on the host”. After birth, our intestine is colonized by microbes like Escherichia coli, Clostridium spp., Streptococcus spp., Lactobacillus spp., Bacteroides spp., and Bifidobacterium spp. Our intestine is an extremely complex living system that participates in the protection of host through a strong defence against external aggregations. The microbial ecosystem of the intestine includes many native species of Bacteroides and Firmicutes that permanently colonize the gastrointestinal tract. The composition of flora changes over time depending upon diet and medical emergencies which leads to the diseased condition. Probiotics exert their mode of action by altering the local environment of the gut by competing with the pathogens, bacteriocins production, H2O2 production etc. Obesity is one of the major health problems and is considered as the most prevalent form of inappropriate nutrition. Probiotics like Lactobacillus Sp., Bifidobacterium Sp., Streptococcus Sp. are successfully used in the treatment of obesity proved in clinical trials. Faecal microbiota transplant (FMT), also known as a stool transplant, is the process of transplantation of Faecal bacteria from a healthy donor into a recipient’s gut to restore normal flora in the recipient. The therapeutic principle on which FMT works is microbes and their functions and metabolites produced by them which are used to treat a variety of diseases. The present review focuses on the role of gastrointestinal microbiome, probiotic selection criteria, their applications and FMT to treat diseases.

New pyran derivative with antioxidant and anticancer properties isolated from the probiotic Lactobacillus plantarum H24 strain

This work was aimed to prepare, isolate and identify antioxidant and cytotoxic compound from the culture filtrate of a probiotic lactobacillus strain. New compound, plantarone (1), together with two known compounds, kojic acid (2) and methyl dodecanoate (3), were isolated from the ethyl acetate extract of the culture filtrate of probiotic Lactobacillus plantarum H24. Their structures were elucidated using spectroscopic methods including 2 D NMR, HRMS analyses. Isolated compounds were screened for antioxidant and cytotoxic activities against Caco-2 colon cancer cells. Compounds 1 and 2 showed lowers DPPH radical scavenging activities (p < 0.05) with IC₅₀ values of 66.3 ± 0.34 μM and 50.2 ± 0.28 μM respectively, compared to standard butylated hydroxyanisole (BHA: IC₅₀ = 44.2 ± 0.24 μM). Whereas only compound 1 showed a good cytotoxicity activity with inhibition value of 60.72 ± 3.55%. Accordingly, L. plantarum H24 could be used to prevent oxidative stress and its injuries, improving human health.

Probiotic Cocktail Identified by Microbial Network Analysis Inhibits Growth, Virulence Gene Expression, and Host Cell Colonization of Vancomycin-Resistant Enterococci

The prevalence of vancomycin resistant enterococcus (VRE) carrier-state has been increasing in patients of intensive care unit and it would be a public health threat. Different research groups conducted decolonizing VRE with probiotic and the results were controversial. Therefore, a systemic approach to search for the probiotic species capable of decolonizing VRE is necessary. Thus, VRE was co-cultured with ten probiotic species. The fluctuations of each bacterial population were analyzed by 16S rRNA sequencing. Microbial network analysis (MNA) was exploited to identify the most critical species in inhibiting the VRE population. The MNA-selected probiotic cocktail was then validated for its efficacy in inhibiting VRE, decolonizing VRE from Caco-2 cells via three approaches: exclusion, competition, and displacement. Finally, the expression of VRE virulence genes after co-incubation with the probiotic cocktail were analyzed with quantitative real-time PCR (qRT-PCR). The MNA-selected probiotic cocktail includes Bacillus coagulans, Lactobacillus rhamnosus GG, Lactobacillus reuteri, and Lactobacillus acidophilus. This probiotic combination significantly reduces the population of co-cultured VRE and prevents VRE from binding to Caco-2 cells by down-regulating several host-adhesion genes of VRE. Our results suggested the potential of this four-strain probiotic cocktail in clinical application for the decolonization of VRE in human gut.

Probiotics Upregulate Trefoil Factors and Downregulate Pepsinogen in the Mouse Stomach

Probiotics are used in the management of some gastrointestinal diseases. However, little is known about their effects on normal gastric epithelial biology. The aim of this study was to explore how the probiotic mixture VSL#3 affects gastric cell lineages in mice with a special focus on protective and aggressive factors. Weight-matching littermate male mice (n = 14) were divided into treated and control pairs. The treated mice received VSL#3 (5 mg/day/mouse) by gastric gavage for 10 days. Control mice received only the vehicle. Food consumption and bodyweight were monitored. All mice were injected intraperitoneally with bromodeoxyuridine (120 mg/Kg bodyweight) two hours before sacrificed to label S-phase cells. Stomach tissues were processed for lectin- and immunohistochemical examination. ImageJ software was used to quantify immunolabeled gastric epithelial cells. Real-time quantitative polymerase chain reaction was used to provide relative changes in expression of gastric cell lineages specific genes. Results revealed that treated mice acquired (i) increased production of mucus, trefoil factor (TFF) 1 and TFF2, (ii) decreased production of pepsinogen, and (iii) increased ghrelin-secreting cells. No significant changes were observed in bodyweight, food consumption, cell proliferation, or parietal cells. Therefore, VSL#3 administration amplifies specific cell types specialized in the protection of the gastric epithelium.

Parkinson's Disease and Current Treatments for Its Gastrointestinal Neurogastromotility Effects

PURPOSE OF REVIEW

Gastrointestinal disturbances are seen in nearly all patients with Parkinson's disease and lead to impaired quality of life, affect drug pharmacodynamics, and potentially worsen patient's existing motor fluctuations, leading to further disability. Recent evidence links abnormal accumulations of α-synuclein aggregates in the periphery (gut) as seen in the cortex which causes dysfunctions impacting every level of the gastrointestinal tract from the esophagus, to the stomach, small bowel, colon, and rectum and can even predate the onset of the central neurologic disorder itself. Many treatments exist for the clinical phenotypes that result from the autonomic dysfunction and neuropathy involved in this neurodegenerative disorder. The treatments for the gut dysfunction seen in Parkinson's disease (PD) depend on the specific area of the gastrointestinal tract affected. For dysphagia, behavioral therapies with speech pathology, neuromuscular electrical stimulation, or botulinum toxin injection may be helpful. For gastroparesis, domperidone may serve as an antiemetic while also blunting the hypotensive potential of Levodopa while new treatments such as ghrelin agonists may prove beneficial to help appetite, satiety, gastric emptying in those with constipation, and even improve constipation. Antibiotics such as rifaximin with poor systemic absorption may be used to treat small bacterial overgrowth also found in those with PD while the benefits of probiotics is yet to be determined. Finally, constipation in PD can be a reflection of pelvic floor dyssynergia, slow transit constipation, or both, thus treatments targeting the specific anorectal dysfunction is necessary for better outcomes.

Evaluation of antimicrobial activity and probiotic properties of wild-strain Pichia kudriavzevii isolated from frozen idli batter

The present research was undertaken to study the probiotic characteristics of Pichia kudriavzevii isolated from frozen idli batter. Polymerase chain reaction amplification with 18S rRNA primers confirmed Pichia kudriavzevii, a xylose-utilizing probiotic strain. It was resistant to physiological concentrations of bile salts, pepsin and pancreatic enzyme. It also showed efficient auto-aggregation as well as co-aggregation ability with four commercial probiotic yeasts and exhibited good hydrophobicity in xylene and toluene. The strain inhibited the growth of 13 enteropathogens and showed a commensal relationship with four commercial probiotic yeast and bacteria. Moreover, it was resistant to 30 antibiotics with different modes of action. The yeast exhibited thermotolerance up to 95 °C for 2 h. The cell-free supernatants were also found to be heat stable, indicating the presence of thermostable secondary metabolites. Hence it could be exploited as starter culture, co-culture or probiotic in the preparation of fermented products or incorporated in heatable foods as well. Copyright © 2016 John Wiley & Sons, Ltd.

Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk

Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents.

The administration of probiotics and synbiotics in immune compromised adults: is it safe?

This study aimed to systematically evaluate safety of probiotics and synbiotics in immune compromised adults (≥18 years). Safety was analysed using the Common Terminology Clinical Adverse Events (CTCAE version 4.0) classification, thereby providing an update on previous reports using the most recent available clinical data (2008-2013). Safety aspects are represented and related to number of participants per probiotic strain/culture, study duration, dosage, clinical condition and selected afflictions. Analysis of 57 clinical studies indicates that probiotic and/or synbiotic administration in immune compromised adults is safe with regard to the current evaluated probiotic strains, dosages and duration. Individuals were considered immune compromised if HIV-infected, critically ill, underwent surgery or had an organ- or an autoimmune disease. There were no major safety concerns in the study, as none of the serious adverse events (AE)s were related, or suspected to be related, to the probiotic or synbiotic product and the study products were well tolerated. Overall, AEs occurred less frequent in immune compromised subjects receiving probiotics and/or synbiotics compared to the control group. In addition, the results demonstrated a flaw in precise reporting and classification of AE in most studies. Furthermore, generalisability 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. We argue that standardised reporting on adverse events (CTCAE) in 'food' studies should be obligatory, thereby improving reliability of data and re-enforcing the safety profile of probiotics.

The therapeutic use of symbiotics

INTRODUCTION

Functional foods are health promoters and their use is associated with reduced risk of chronic degenerative and non-transmissible diseases. Examples are symbiotic. The association of one (or more) probiotic with a one (or more) prebiotic is called symbiotic, being the prebiotics complementary and probiotics synergistic, thus presenting a multiplicative factor on their individual actions.

OBJECTIVE

To assess the evidences on the benefits of the use of symbiotics in the treatment of clinical and surgical situations.

METHODS

The headings symbiotic, probiotic and prebiotic were searched in Pubmed/Medline in the last 15 years, and were selected 25 articles, used for database.

RESULTS

The use of symbiotic may promote an increase in the number of bifidobacteria, glycemic control, reduction of blood cholesterol, balancing the intestinal flora which aids in reducing constipation and/or diarrhea, improves intestinal permeability and stimulation of the immune system. Clinical indications for these products has been expanded, in order to maximize the individual's physiological functions to provide greater. So, with the high interest in the clinical and nutritional control of disease, many studies have been conducted demonstrating the effectiveness of using symbiotic in improving and/or preventing various and/or symptoms of gastrointestinal diseases.

CONCLUSION

Symbiotic behave differently and positively in various pathological situations.

A potential role of probiotics in colorectal cancer prevention: review of possible mechanisms of action

A number of investigations, mainly using in vitro and animal models, have demonstrated a wide range of possible mechanisms, by which probiotics may play a role in colorectal cancer (CRC) prevention. In this context, the most well studied probiotics are certain strains from the genera of lactobacilli and bifidobacteria. The reported anti-CRC mechanisms of probiotics encompass intraluminal, systemic, and direct effects on intestinal mucosa. Intraluminal effects detailed in this review include competitive exclusion of pathogenic intestinal flora, alteration of intestinal microflora enzyme activity, reduction of carcinogenic secondary bile acids, binding of carcinogens and mutagens, and increasing short chain fatty acids production. Reduction of DNA damage and suppression of aberrant crypt foci formation have been well demonstrated as direct anti-CRC effects of probiotics on intestinal mucosa. Existing evidence clearly support a multifaceted immunomodulatory role of probiotics in CRC, particularly its ability to modulate intestinal inflammation, a well known risk factor for CRC. The effectiveness of probiotics in CRC prevention is dependent on the strain of the microorganism, while viability may not be a prerequisite for certain probiotic anticancer mechanisms, as indicated by several studies. Emerging data suggest synbiotic as a more effective approach than either prebiotics or probiotics alone. More in vivo especially human studies are warranted to further elucidate and confirm the potential role of probiotics (viable and non-viable), prebiotics and synbiotics in CRC chemoprevention.

Differences in vaginal lactobacilli composition of Iranian healthy and bacterial vaginosis infected women: a comparative analysis of their cytotoxic effects with commercial vaginal probiotics

BACKGROUND

Vaginal flora of healthy women is dominated by Lactobacillus species which can prevent bacterial vaginosis.

OBJECTIVES

The current study aimed to determine the differences in vaginal lactobacilli composition of Iranian healthy and bacterial vaginosis (BV) infected women and compared their cytotoxic effects with commercial vaginal probiotics.

PATIENTS AND METHODS

One hundred and seventy eight vaginal specimens were collected from healthy and BV infected women. Lactobacillus colonies were obtained by culturing on laked blood BHI and MRS medias and genetically defined by 16s rRNA sequencing. Differentiating the specimens to normal, intermediate and BV infected were carried out by Ison and Hey grading protocol. Identification of Lactobacillus strains in vaginal specimens were performed by Multiplex PCR. The inhibitory effects of lactobacilli on Hela (tumoral cervical cells) and HNCF-pi52 (normal cervical cells) were conducted by MTT and trypan blue assays.

RESULTS

L. crispatus, L. gasseri, L. iners, L. jensenii, L. acidophilus and L. rhamnosus were the most frequently occurring species in vagina of healthy Iranian women. L. crispatus and L. jensenni were significantly higher in the normal than in the BV infected groups. Also the cytotoxic effect of L. crispatus on tumoral cervical cells was higher than other lactobacilli including commercial probiotics.

CONCLUSIONS

As L. crispatus and L. jensenni were significantly higher in BV infected women and the cytotoxic effect of L. crispatus on tumoral cervical cells was high, introduction of new probiotics seems necessary.

Influence of consumption of probiotics on presence of enterobacteria in the oral cavity

Clinical benefits of probiotics have been clearly reported in different gastrointestinal disorders, many of them caused by enterobacteria. The oral cavity is a port of entry and can be an important reservoir of these microorganisms. This work evaluated whether consumption of probiotics was able to influence the presence of enterobacteria in the oral cavity and the specific secretory response against these microorganisms. Saliva samples of healthy individuals were collected and plated in MacConkey agar. Carriers of Gram-negative, rod-shaped microorganisms in the oral cavity were selected and instructed to use the probiotic Yakult LB for 20 days. Saliva was then collected and enterobacteria species were identified using the API 20 E system and by ELISA using anti-enterobacteria IgA. The results showed reduction in the prevalence of enterobacteria, but no significant changes in enterobacterial counts (log CFU/mL; p = 0.3457). The species most frequently isolated were Enterobacter cloacae and Klebsiella oxytoca, both before and after probiotic consumption. No significant changes were observed in anti-enterobacteria IgA levels. In conclusion, probiotic consumption had some influence on enterobacterial presence in the oral cavity, but did not affect enterobacterial counts or the specific immune secretory response against them.

Probiotics and prebiotics in pediatrics

This clinical report reviews the currently known health benefits of probiotic and prebiotic products, including those added to commercially available infant formula and other food products for use in children. Probiotics are supplements or foods that contain viable microorganisms that cause alterations of the microflora of the host. Use of probiotics has been shown to be modestly effective in randomized clinical trials (RCTs) in (1) treating acute viral gastroenteritis in healthy children; and (2) preventing antibiotic-associated diarrhea in healthy children. There is some evidence that probiotics prevent necrotizing enterocolitis in very low birth weight infants (birth weight between 1000 and 1500 g), but more studies are needed. The results of RCTs in which probiotics were used to treat childhood Helicobacter pylori gastritis, irritable bowel syndrome, chronic ulcerative colitis, and infantile colic, as well as in preventing childhood atopy, although encouraging, are preliminary and require further confirmation. Probiotics have not been proven to be beneficial in treating or preventing human cancers or in treating children with Crohn disease. There are also safety concerns with the use of probiotics in infants and children who are immunocompromised, chronically debilitated, or seriously ill with indwelling medical devices. Prebiotics are supplements or foods that contain a nondigestible food ingredient that selectively stimulates the favorable growth and/or activity of indigenous probiotic bacteria. Human milk contains substantial quantities of prebiotics. There is a paucity of RCTs examining prebiotics in children, although there may be some long-term benefit of prebiotics for the prevention of atopic eczema and common infections in healthy infants. Confirmatory well-designed clinical research studies are necessary.

Evaluation of the intestinal colonization by microencapsulated probiotic bacteria in comparison with the same uncoated strains

BACKGROUND

Beneficial findings concerning probiotics are increasing day by day. However, one of the most important parameter which affects the probiotic activity of a microorganism is its survival during the gastroduodenal transit. Some microencapsulation techniques could be applied to bacterial cells to improve this parameter.

METHODS

A comparison between the intestinal colonization by microencapsulated bacteria and the same not microencapsulated strains has been conducted in a double blind, randomized, cross-over study. The study (April to July 2005) involved 44 healthy volunteers. In particular, participants were divided into 2 groups: group A (21 participants) received a mix of probiotic strains Lactobacillus plantarum LP01 (LMG P-21021) and Bifidobacterium breve BR03 (DSM 16604) in an uncoated form, group B (23 participants) was given the same strains microencapsulated with a gastroresistant material. The not microencapsulated strains were administered at 5 x 10(9) colony forming units/strain/d for 21 days, whereas the microencapsulated bacteria were given at 1 x 10(9) colony forming units/strain/d for 21 days. At the end of the first period of treatment with probiotics a 3 weeks washout phase has been included in the study protocol. At the end of the washout period the groups were crossed: in detail, group A had the microencapsulated and group B the uncoated bacteria. The administered amounts of each strain were the same as the first treatment. The quantitative evaluation of intestinal colonization by strains microencapsulated or not microencapsulated was made by fecal samples examination at the beginning of the clinical trial, after 10 and 21 days of each treatment period. In particular, fecal heterofermentative Lactobacilli and Bifidobacteria have been counted.

RESULTS

A statistically significant increase in the fecal amounts of Lactobacilli and Bifidobacteria was recorded in both groups at the end of each treatment compared with d0 or d42 (P<0.0001 and P<0.0001 at d21, P<0.0001 and P<0.0001 at d63 for Lactobacilli and Bifidobacteria, respectively), confirming the ability of the 2 strains to colonize the human gut, either in a gastroprotected form or not. Participants treated with the microencapsulated bacteria reported a kinetics of intestinal colonization quite similar to participants who received not coated strains.

CONCLUSIONS

Probiotics are able to exert many different beneficial effects on the human host. These effects are mediated by the number of viable cells which reach the gut. The microencapsulation technique used in this study is a valid strategy to significantly improve gastroresistance of strains, thus enhancing their probiotic activity and allowing the use of a 5 times lower amount.

Probiotics in the critically ill patient: a double blind, randomized, placebo-controlled trial

PURPOSE

Probiotics have been shown to be able to restore a non-pathogenic digestive flora, to prevent digestive colonization by pathogenic bacteria, and to modulate immunity. The aim of this study was to assess the effects of prophylactic probiotic administration in patients ventilated for up to 2 days.

METHODS

This study was performed as a double-blind, concealed randomized, placebo-controlled trial in a French medical intensive care unit (ICU). Adult patients mechanically ventilated for a period of more than 48 h received enterally administered probiotics (Ergyphilus, 2 x 10(10) lactic acid bacteria, mostly Lactobacillus rhamnosus GG, once a day) or placebo until successful weaning.

RESULTS

A total of 167 patients were included. The two groups were comparable at baseline. The 28-day mortality rates were not different in the probiotic (25.3%) and placebo groups (23.7%). Mortality rates in ICU and at 90 days were also unaffected by the treatment. The incidence of ICU-acquired infections did not differ significantly except for that of catheter-related bloodstream infections that was lowered by probiotics. On a prespecified subgroup analysis, we found a reduction of the 28-day mortality among severe sepsis patients (total n = 101) treated with probiotics (n = 52) with an odds ratio (OR) for death at 0.38 (95% CI 0.16-0.93, p = 0.035). By contrast, probiotics were associated with a higher mortality rate in non-severe sepsis patients (OR 3.09, 95% CI 0.87-11.01, p = 0.08).

CONCLUSIONS

Although numerous uncertainties remain (type and the number of strains to use, delay and length of administration), and despite an acceptable safety profile, the daily prophylactic administration of probiotics cannot be encouraged in the critically ill patient.

Probiotics: preventing antibiotic-associated diarrhea

PURPOSE

Probiotics are live microorganisms that offer a health benefit to the host. Found typically in dietary supplements, probiotics can be safely used in the treatment of acute diarrheal disease, inflammatory bowel disease, and antibiotic-associated diarrhea. They can be found in milks, yogurt, powders, and pills.

CONCLUSIONS

Research has shown that several strains of probiotics are helpful in the prevention and treatment of antibiotic-associated diarrhea. The most commonly studied probiotics are Lactobacillus GG and Saccharomyces boulardii.

PRACTICE IMPLICATIONS

By understanding the uses, dosages, and safety of common probiotics, nurses can help educate patients and their families on the benefits of probiotics.

Role of the host defense system and intestinal microbial flora in the pathogenesis of necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating disease that affects primarily the intestine of premature infants. Despite recent advances in neonatology, NEC remains a major cause of morbidity and mortality in neonates. Neonatal mucosal defenses and adherence of bacterial pathogens may play an important role in the pathogenesis of NEC.

METHODS

Review and synthesis of pertinent literature.

RESULTS

Putative factors that have been implicated in the pathogenesis of NEC include abnormal patterns of gut colonization by bacteria, immaturity of the host immune system and mucosal defense mechanisms, intestinal ischemia, formula feeding, and loss of intestinal epithelial barrier integrity.

CONCLUSION

Host defenses and intestinal microbial ecology are believed to play important roles in the pathogenesis of NEC. Commensal bacteria and probiotic therapy may be of therapeutic utility in the maintenance of the gut epithelial barrier.

Interaction of early diet and the development of the immune system

The present review focuses on the specific effects of nutrients on the development of the immune system in early life. There is a big gap regarding the specific mechanisms that regulate immunity at the intestinal level and their impact in the systemic immune function. For this reason, during the last few years there has been great interest in ascertaining the mechanisms that regulate the intestinal immune function, as well as to understand how specific nutrients interact with the gut-associated lymphoid tissue. We have reviewed this topic with special emphasis on how human milk, and its components, influence the early development of intestinal immunity in breast-fed infants compared with formula-fed infants. Interactions between nutrients and intestinal microbiota have also been reviewed. Some micronutrients such as nucleotides and gangliosides, which are present in human milk and also in most foods, are able to influence immune functionality at very low concentrations. The specific action of these micronutrients on some parameters of immunity, as well as their potential mechanisms of action, have been considered in detail. However, there are limited data on how other specific nutrients, namely protein and non-protein N-containing compounds, lipids, carbohydrates, and others, such as minerals, vitamins, fibre, non-nutritional dietary compounds (flavonoids, carotenoids, phyto-oestrogens, etc), influence immunity. In the present review we have provided data regarding the potential effects of these compounds on the immune response in early life. The increasing use of functional foods by the public to improve their general health and prevent the incidence of chronic diseases has become a major area of interest within the nutrition community. Of the many functional foods available, probiotics have been most studied in infancy and childhood, particularly with regard to the prevention of allergic diseases. Infant formulae and fermented milks containing large quantities of probiotics are produced and consumed by Europeans and in other industrialized countries. In the present review we cover the clinical effects of probiotics in preventing disease during early life, as well as the potential mechanisms of interaction between probiotics and the gastrointestinal tract.

Persistence of colicinogenic Escherichia coli in the mouse gastrointestinal tract

BACKGROUND

The ability of a bacterial strain to competitively exclude or displace other strains can be attributed to the production of narrow spectrum antimicrobials, the bacteriocins. In an attempt to evaluate the importance of bacteriocin production for Escherichia coli strain residence in the gastrointestinal tract, a murine model experimental evolution study was undertaken.

RESULTS

Six colicin-producing, yet otherwise isogenic, E. coli strains were administered and established in the large intestine of streptomycin-treated mice. The strains' persistence, population density, and doubling time were monitored over a period of 112 days. Early in the experiment only minor differences in population density between the various colicin-producing and the non-producing control strains were detected. However, over time, the density of the control strains plummeted, while that of the colicin-producing strains remained significantly higher (F(7,66) = 2.317; P < 0.0008).

CONCLUSION

The data presented here support prior claims that bacteriocin production may play a significant role in the colonization of E. coli in the gastrointestinal tract. Further, this study suggests that the ability to produce bacteriocins may prove to be a critical factor in determining the success of establishing probiotic E. coli in the gastrointestinal tract of humans and animals.

Probiotic E. coli treatment mediates antimicrobial human beta-defensin synthesis and fecal excretion in humans

Inducible epithelial human beta-defensins (hBD) play an important role in intestinal barrier function. In vitro studies showed that clinically effective probiotics induce antimicrobial hBD-2. Here, we aimed to assess the in vivo effect in healthy volunteers and also addressed how defensins affect probiotic survival. Symbioflor 2 containing one strain of several viable genotypes of Escherichia coli was administered to 23 healthy individuals. After 3 weeks, fecal hBD-2 peptide was increased in 78% (mean 3.7-fold; P<0.0001). Interestingly, the fecal hBD-2 peptide was still elevated 9 weeks after treatment (P=0.008). In vitro studies revealed that this effect was mediated by only one out of three tested E. coli genotypes and comparable to probiotic E. coli Nissle 1917 (10- to 15-fold). Functional assays showed that all tested bacteria were similarly killed by defensins allowing to speculate about a suicidal character of this effect. Defensin induction seems to be a common and important mechanism of probiotic treatment.

The dual role of bacteriocins as anti- and probiotics

Bacteria employed in probiotic applications help to maintain or restore a host's natural microbial floral. The ability of probiotic bacteria to successfully outcompete undesired species is often due to, or enhanced by, the production of potent antimicrobial toxins. The most commonly encountered of these are bacteriocins, a large and functionally diverse family of antimicrobials found in all major lineages of Bacteria. Recent studies reveal that these proteinaceous toxins play a critical role in mediating competitive dynamics between bacterial strains and closely related species. The potential use of bacteriocin-producing strains as probiotic and bioprotective agents has recently received increased attention. This review will report on recent efforts involving the use of such strains, with a particular focus on emerging probiotic therapies for humans, livestock, and aquaculture.

Milk fermented by Lactobacillus gasseri SBT2055 influences adipocyte size via inhibition of dietary fat absorption in Zucker rats

We have demonstrated previously that a diet containing skimmed milk (SM) fermented by Lactobacillus gasseri SBT2055 (LGSP) reduces adipocyte size in Sprague-Dawley rats. Two experiments were conducted to extend these observations in order to elucidate the mechanism involved. In experiment 1, lean and obese Zucker rats were fed a diet containing SM or LGSP for 4 weeks. The LGSP diet, compared with the SM diet, resulted in lowering of the mesenteric adipose tissue weight (23 %; P < 0.05), adipocyte sizes (28 %; P < 0.001) and serum leptin concentration (36 %; P < 0.05) in lean rats. Obese Zucker rats did not display such dietary effects. Only the number of smaller adipocytes was increased (P < 0.05) by the LGSP diet in the subcutaneous adipose tissue of obese rats. The LGSP diet significantly reduced the serum and hepatic cholesterol in rats. In addition, the LGSP diet led to an increased excretion of faecal fatty acids and total neutral faecal sterols in both rat strains. In experiment 2, Sprague-Dawley rats with permanent cannulation of the thoracic duct were fed either the SM or LGSP diets and their lymph was collected. The LGSP diet lowered the maximum transport rate of TAG and phospholipids. These results indicate that fermented milk regulates adipose tissue growth through inhibition at the stage of dietary fat absorption in lean Zucker rats.

Fate and effects of Camembert cheese micro-organisms in the human colonic microbiota of healthy volunteers after regular Camembert consumption

The objective of this study was to determine i) if Camembert cheese micro-organisms could be detected in fecal samples after regular consumption by human subjects and ii) the consequence of this consumption on global metabolic activities of the host colonic microbiota. An open human protocol was designed where 12 healthy volunteers were included: a 2-week period of fermented products exclusion followed by a 4-weeks Camembert ingestion period where 2x40 g/day of Camembert cheese was consumed. Stools were collected from the volunteers before consumption, twice during the ingestion period (2nd and 4th week) and once after a wash out period of 2 weeks. During the consumption of Camembert cheese, high levels of Lactococcus lactis and Leuconostoc mesenteroides were measured in fecal samples using real-time quantitative PCR, reaching median values of 8.2 and 7.5 Log(10) genome equivalents/g of stool. For Ln. mesenteroides, persistence was observed 15 days after the end of Camembert consumption. The survival of Geotrichum candidum was also assessed and the fecal concentration reached a median level of 7.1 Log(10) CFU/g in stools. Except a decreasing trend of the nitrate reductase activity, no significant modification was shown in the metabolic activities during this study.

Human gut microbiota and bifidobacteria: from composition to functionality

The human gut is the home of an estimated 10(18) bacterial cells, many of which are uncharacterized or unculturable. Novel culture-independent approaches have revealed that the majority of the human gut microbiota consists of members of the phyla Bacteroidetes and Firmicutes. Nevertheless the role of bifidobacteria in gut ecology illustrates the importance of Actinomycetes and other Actinobacteria that may be underestimated. The human gut microbiota represents an extremely complex microbial community the collective genome of which, the microbiome, encodes functions that are believed to have a significant impact on human physiology. The microbiome is assumed to significantly enhance the metabolism of amino and glycan acids, the turnover of xenobiotics, methanogenesis and the biosynthesis of vitamins. Co-colonisation of the gut commensals Bifidobacterium longum and Bacteroides thetaiotaomicron in a murine model system revealed that the presence of bifidobacteria induced an expansion in the diversity of polysaccharides targeted for degradation by Bacteroides and also induced host genes involved in innate immunity. In addition, comparative analysis of individual human gut microbiomes has revealed various strategies that the microbiota use to adapt to the intestinal environment while also pointing to the existence of a distinct infant and adult-type microbiota.

Use of Lactobacillus casei subspecies Rhamnosus GG and gastrointestinal colonization by Candida species in preterm neonates

Candida species increasingly cause morbidity and mortality in the premature infant in neonatal intensive care units, and the gut reservoir is the site from which dissemination most frequently starts in such patients. Specific antifungal prophylaxis is the most suitable strategy with which to limit the severity and the frequent neurodevelopmental impairment in survivors that is associated with neonatal invasive fungal infections. Recent interest has focused on the use of probiotics for the treatment of several diseases in neonatal patients. Pilot studies have implicated these organisms in necrotizing enterocolitis, sepsis, and urinary tract infections. Other applications of probiotic therapy in preterm neonates may also include the prevention of fungal colonization and of Candida-related disorders. Probiotics could provide an innovative and less invasive approach because they modify the bowel flora by colonizing the gastrointestinal tract. Basic research has shown that in mice models, the Lactobacillus casei subsp Rhamnosus GG (LGG) is effective in preventing Candida gut colonization and systemic dissemination. A pilot, randomized, double-blind, placebo-controlled trial in human preterm neonates has demonstrated that LGG administered in the first month of life significantly reduces enteric Candida colonization. The present article summarizes the state of the art about probiotics and Candida-related diseases in the preterm neonate and emphasizes the need for further investigations to determine unequivocally the possible role of LGG in the prevention and management of the fungal diseases in preterm neonates.

Effect of probiotics on intestinal regrowth and bacterial translocation after massive small bowel resection in a rat

BACKGROUND/PURPOSE

Because of their ability to inhibit intestinal bacterial overgrowth, probiotics (PROs) have been advocated for the treatment of patients with short bowel syndrome (SBS). This study was conducted to determine the effect of PROs on bacterial translocation and intestinal regrowth after massive small bowel resection in a rat.

METHODS

Male Sprague-Dawley rats were divided into 3 experimental groups: sham rats underwent bowel transection and reanastomosis, SBS rats underwent 75% small bowel resection, and SBS-PRO rats underwent bowel resection and were treated with a PRO given in drinking water from day 4 through 14. Intestinal structural changes (bowel circumference, overall bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, enterocyte proliferation and enterocyte apoptosis) and bacterial translocation (BT) to mesenteric lymph nodes, liver, portal blood, and peripheral blood were determined on day 15 after operation.

RESULTS

Sham rats exhibited a 20% BT to the mesenteric lymph nodes (level I), liver (level II), and blood (level III). Short bowel syndrome rats demonstrated a 100% BT to lymph nodes (level I) and liver (level II) and 40% translocation to peripheral blood (level III). Treatment with PROs resulted in a significant decrease in BT to all 3 target organs and decreased enterocyte apoptosis compared with SBS-untreated animals. Short bowel syndrome rats showed a significant increase (vs sham) in jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth. Short bowel syndrome rats also had a greater proliferation index and apoptotic index in both jejunum and ileum compared with sham animals. SBS-PRO rats showed a significant increase (vs SBS rats) in crypt depth in ileum and a mild decrease in apoptotic index in jejunum and ileum, compared with SBS-untreated animals.

CONCLUSIONS

In a rat model of SBS, PROs decrease BT through mechanisms which maybe dependent on intestinal mucosal integrity.

Use of probiotics in pediatrics: rationale, mechanisms of action, and practical aspects

The use of probiotics (ingested microbes that can modify intestinal microbial populations in a way that benefit the host) has moved from concept to actual demonstration of specific benefits by specific microorganisms for specific populations. It is increasingly clear that these benefits to the host are mostly mediated by the profound effect that intestinal microflora (microbiota) have on gut barrier function and host immune response. Intestinal bacteria are more numerous than the human cells of the host that harbors them. Despite having many potential pathogens in this microflora, humans do not routinely get infected. It is no coincidence that gut-associated immune tissue constitutes approximately 80% of all immunologically active cells in the human host. The gut interacts with intestinal bacteria, both resident and ingested, to develop protective mechanisms (via improving gut barrier function and immune stimulation for defense) and appropriate, nonexaggerated responses (via immune modulation and immune tolerance) to support host health. The mechanisms of this interaction between host and bacteria are increasingly being unraveled and in great part explain the clinical benefits that have been reported with specific probiotic bacteria by enhancing host defense mechanisms (such as for treatment and prevention of viral diarrhea and reducing risk of necrotizing enterocolitis), mitigating antibiotic-associated diarrhea, and modulating host immune response (such as in allergic disease).

Genomic and metabolic studies of the impact of probiotics on a model gut symbiont and host

Probiotics are deliberately ingested preparations of live bacterial species that confer health benefits on the host. Many of these species are associated with the fermentation of dairy products. Despite their increasing use, the molecular details of the impact of various probiotic preparations on resident members of the gut microbiota and the host are generally lacking. To address this issue, we colonized germ-free mice with Bacteroides thetaiotaomicron, a prominent component of the adult human gut microbiota, and Bifidobacterium longum, a minor member but a commonly used probiotic. Simultaneous whole genome transcriptional profiling of both bacterial species in their gut habitat and of the intestinal epithelium, combined with mass-spectrometric analysis of habitat-associated carbohydrates, revealed that the presence of B. longum elicits an expansion in the diversity of polysaccharides targeted for degradation by B. thetaiotaomicron (e.g., mannose- and xylose-containing glycans), and induces host genes involved in innate immunity. Although the overall transcriptome expressed by B. thetaiotaomicron when it encounters B. longum in the cecum is dependent upon the genetic background of the mouse (as assessed by a mixed analysis of variance [ANOVA] model of co-colonization experiments performed in NMRI and C57BL/6J animals), B. thetaiotaomicron's expanded capacity to utilize polysaccharides occurs independently of host genotype, and is also observed with a fermented dairy product-associated strain, Lactobacillus casei. This gnotobiotic mouse model provides a controlled case study of how a resident symbiont and a probiotic species adapt their substrate utilization in response to one another, and illustrates both the generality and specificity of the relationship between a host, a component of its microbiota, and intentionally consumed microbial species.

A gnotobiotic mouse model enabled transcriptional profiling of both host and bacteria. This provides insights into the intestinal response to colonization and reveals how all organisms involved adapt and respond to one another.

Safety and Tolerance of a Probiotic Formula in Early Infancy Comparing Two Probiotic Agents: A Pilot Study

OBJECTIVE

To compare the safety and tolerance of two formulas, supplemented with different probiotic agents, in early infancy.

DESIGN

Prospective randomized placebo-controlled trial.

SETTING

Clinics of a University Medical Center.

SUBJECTS

Full-term healthy infants aged less than 4 months.

INTERVENTION

Infants were randomly assigned for 4 weeks to a standard milk-based formula supplemented with either Bifidobacterium lactis (BB-12), Lactobacillus reuteri (ATCC 55730) or a probiotics-free formula.

MEASURES OF OUTCOME

Growth parameters, daily characteristics of feeding, stooling and behavior, and side effects.

RESULTS

Fifty-nine infants, aged 3-65 days, were included. Subjects in all three groups were similar at entry in terms of gestational age, birth weight, sex, growth parameters and breast feeding rate prior to the study. The supplemented formulas were well accepted and did not reveal any adverse effects. A comparison of growth parameters, and variables of feeding, stooling and crying and irritability did not reveal any significant differences between groups.

CONCLUSIONS

The use of formula supplemented with either Lactobacillus reuteri or Bifidobacterium lactis in early infancy, was safe, well tolerated and did not adversely affect growth, stooling habits or infant behavior.

Évaluation d'une préparation pour nourrissons à teneur réduite en protéines et enrichie en probiotiques, en relais de l'allaitement maternel

Besides assuring growth and development in early infancy, human breast milk plays a key role in preventing infections, in particular by favouring the growth of bifidobacteria. The development of infant formulas containing probiotic agents consequently represents a significant advance in the provision of an optimal alternative to breast feeding when this is not feasible. A further concern is to avoid an excessively high protein content relative to breast milk, potentially favouring obesity in later life.

OBJECTIVES

The objective of this open Multicenter comparative study was to demonstrate that a new infant formula, characterized by a reduced protein content and the presence of a probiotic agent, was as effective as conventional formulas in assuring growth during the first months of life.

POPULATION AND METHODS

The study population comprised full-term healthy infants with an age at inclusion of 1-28 days, whose mothers no longer wished to continue breast feeding or were unable to breast feed. The test formula (GE), enriched with Bifidobacterium lactis, had a protein content of 1.5 g/100 ml. The primary end point was daily weight gain from day 0 to day 90. Secondary end points were daily increase in height and cranial circumference, overall and gastrointestinal tolerance and formula acceptability. A total of 203 infants were included in the analysis, 117 receiving GE and 86 the formula habitually prescribed by the paediatrician.

RESULTS

Daily gains in weight, height and cranial circumference did not differ significantly between the groups. The rates of overall and gastrointestinal adverse events were comparable in the two groups and the acceptability of GE was consistently good, similar to that of the standard formulas.

CONCLUSION

The results of this study demonstrated that the new probiotic infant formula GE has equivalent efficacy to conventional formulas in achieving growth in early infancy, and is well tolerated.

The probiotic bacterium Lactobacillus plantarum species 299 reduces intestinal permeability in experimental biliary obstruction

AIMS

Extrahepatic biliary obstruction is associated with the failure of intestinal barrier function, allowing bacteria and other substances from the intestine to enter the circulation and initiate a systemic inflammatory response, causing impairment of organ function. Probiotic bacteria have been shown to have beneficial effects on intestinal barrier function in other conditions, but their effects have never been studied in biliary obstruction.

METHODS AND RESULTS

This study examined the effects of enteral administration of Lactobacillus plantarum species 299 (LP299) in oatmeal fibre compared with sterile oatmeal fibre in water or water alone in an animal model of biliary obstruction. Administration of LP299 was associated with reduced intestinal permeability compared with sterile oatmeal alone (0.262 +/- 0.105%vs 0.537 +/- 0.037%, P=0.019, percentage excretion of (14)Carbon), but there was no evidence of reduced endotoxin exposure or blunting of the systemic inflammatory response. Animals receiving sterile oatmeal fibre alone also failed to develop the hyperpermeability after biliary obstruction seen in animals receiving water only (0.512+/- 0.05%vs 0.788 +/- 0.18%), suggesting that oatmeal itself may have some beneficial effects on intestinal barrier function.

CONCLUSION

Enteral administration of the probiotic bacterium LP299 reduces intestinal hyperpermeability associated with experimental biliary obstruction.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides insight to direct further work into the modulation of intestinal barrier function by probiotic bacteria.

Effects ofLactobacillus acidophilusDSM13241 as a probiotic in healthy adult cats

OBJECTIVE

To evaluate the effect of dietary supplementation with the probiotic strain Lactobacillus acidophilus DSM13241 in healthy adult cats.

ANIMALS

15 adult cats.

PROCEDURES

Cats were fed a nutritionally complete dry food for 5 weeks. Fecal character was assessed daily, and a single fecal sample and 3-mL blood sample were collected for bacterial enumeration and hematologic analysis, respectively. Cats were then fed the same diet supplemented with L acidophilus DSM13241 (2 x 10(8) CFU/d) for 4.5 weeks. Repeat fecal and hematologic measurements were taken prior to the return to control diet for a 4-week period.

RESULTS

The probiotic species was recovered from feces, demonstrating survival through the feline gastrointestinal tract. Probiotic supplementation was associated with increased numbers of beneficial Lactobacillus and L acidophilus groups in feces and decreased numbers of Clostridium spp and Enterococcus faecalis, indicating an altered bacterial balance in the gastrointestinal tract microflora. Fecal pH was also decreased suggesting a colonic environment selective for the beneficial lactic acid bacterial population. Systemic and immunomodulatory effects were associated with administration of L acidophilus DSM13241 including altered cell numbers within WBC subsets and enhanced phagocytic capacity in the peripheral granulocyte population. In addition, plasma endotoxin concentrations were decreased during probiotic feeding, and RBCs had a decreased susceptibility to osmotic pressure.

CONCLUSIONS AND CLINICAL RELEVANCE

Probiotic strain L acidophilus DSM13241 fed at 2 x 10(8) CFU/d can alter the balance of gastrointestinal microflora in healthy cats. Furthermore, administration of this probiotic results in beneficial systemic and immunomodulatory effects in cats.

Probiotics as flourishing benefactors for the human body

This article provides a comprehensive review of the beneficial effects of various strains of probiotics in preventing and treating certain diseases. Currently, changed lifestyles as well as the increased use of antibiotics are significant factors challenging the preservation of a healthy intestinal microflora. The concept of probiotics is to restore and uphold a microflora advantageous for the human body. Probiotics are found in a number of fermented dairy products, infant formula, and dietary supplements. In the presence of prebiotics, which are nondigestible food ingredients favorable for probiotic growth, their survival in the intestine is ameliorated.

Gastrointestinal maturation and feeding

The intestine serves not only as a digestive absorptive organ, it is also one of the largest immune organs of the body, has a huge endocrine and exocrine role, and also encompasses neural tissue equivalent to that of the entire spinal cord. The microbial microenvironment also plays a critical role in development. This brief overview of developmental aspects of these intestinal functions will be related to clinical problems in the neonatal period and subsequent health.

Probiotics and the gastrointestinal tract: Where are we in 2005?

Probiotic agents are live microbes or components of microbes that have a positive effect on the host. They exert their action through interplay with the immune system of the host. Some of this effect is local and some is systemic. The full story is yet to be discovered. Probiotics have a definite positive effect on rotavirus diarrhea, post antibiotic diarrhea and pouchitis. Their exact role in inflammatory bowel disease, irritable bowel syndrome, other forms of infectious diarrhea, and prevention of cancer is yet to be determined. This review summarizes the data about probiotics in these conditions.