Prophylactic efficacy of probiotics on travelers' diarrhea: an adaptive meta-analysis of randomized controlled trials

Next generation probiotics: Engineering live biotherapeutics

The population dynamics of the human microbiome have been associated with inflammatory bowel disease, cancer, obesity, autoimmune diseases, and many other human disease states. An emerging paradigm in treatment is the administration of live engineered organisms, also called next-generation probiotics. However, the efficacy of these microbial therapies can be limited by the organism's overall performance in the harsh and nutrient-limited environment of the gut. In this review, we summarize the current state of the art use of bacterial and yeast strains as probiotics, highlight the recent development of genetic tools for engineering new therapeutic functions in these organisms, and report on the latest therapeutic applications of engineered probiotics, including recent clinical trials. We also discuss the supplementation of prebiotics as a method of manipulating the microbiome and improving the overall performance of engineered live biotherapeutics.

Bismuth subsalicylate, probiotics, rifaximin and vaccines for the prevention of travelers' diarrhea: a systematic review and network meta-analysis

Background: Bismuth subsalicylate (BSS), probiotics, rifaximin, and vaccines have been proposed as preventive modalities for patients with travelers' diarrhea (TD), but their comparative effectiveness for prevention has rarely been studied. We aimed to perform a systematic review and network meta-analysis to test whether one of these modalities is more effective than the others in reducing the incidence of TD. Methods: We searched Pubmed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and clinical registries from inception of the databases through 18 November 2023, without language restriction, for randomized controlled trials (RCTs) evaluating the efficacy of BSS, probiotics, rifaximin, and vaccines in preventing TD. The primary outcome was the incidence of TD and the safety outcome was the incidence of adverse events. The relative ratio (RR) was used to assess the effect of the modalities, and RR estimates between any two of the modalities were calculated and pooled using a frequentist network meta-analysis model. Results: Thirty-one studies (recruiting 10,879 participants) were included in the analysis. Sixteen were judged to have a low risk of bias. In the aggregate analysis, BSS and rifaximin were more effective than placebo and other treatment modalities, which was further confirmed in the individual analysis. The comparison between rifaximin and placebo achieved high confidence, while the comparisons between BSS and placebo, ETEC and probiotics, and rifaximin and vaccines achieved moderate confidence. BSS had a higher rate of adverse events compared with other treatments. Conclusion: Rifaximin had a relative lower TD incidence and lower adverse event rate, and the evidence was with moderate confidence. Systematic Review Registration: https://osf.io/dxab6, identifier.

The Potential Impact of Probiotics on Human Health: An Update on Their Health-Promoting Properties

Probiotics, known to be live microorganisms, have been shown to improve or restore the gut microbiota, which in turn has been linked to improved health. It is believed that probiotics are the modern equivalent of a panacea, with claims that they may treat or prevent different diseases both in children and adults (e.g., from colic in babies to cardiovascular disease, respiratory infection, and cancer in adults). Ever since the early 2000s, probiotic-based fermented foods have had a resurgence in popularity, mostly due to claims made regarding their health benefits. Fermented foods have been associated with the prevention of irritable bowel syndrome, lactose intolerance, gastroenteritis, and obesity, but also other conditions such as chronic diarrhea, allergies, dermatitis, and bacterial and viral infections, all of which are closely related to an unhealthy lifestyle. Recent and ongoing developments in microbiome/microbiota science have given us new research directions for probiotics. The new types, mechanisms, and applications studied so far, and those currently under study, have a great potential to change scientific understanding of probiotics' nutritional applications and human health care. The expansion of fields related to the study of the microbiome and the involvement of probiotics in its improvement foreshadow an era of significant changes. An expanding range of candidate probiotic species is emerging that can address newly elucidated data-driven microbial niches and host targets. In the probiotic field, new variants of microbiome-modulating interventions are being developed, including prebiotics, symbiotics, postbiotics, microbial consortia, live biotherapeutic products, and genetically modified organisms, with renewed interest in polyphenols, fibers, and fermented foods to ensure human health. This manuscript aims to analyze recent, emerging, and anticipated trends in probiotics (sources, doses, mechanism of action, diseases for which probiotics are administered, side effects, and risks) and create a vision for the development of related areas of influence in the field.

Controlling Intestinal Infections and Digestive Disorders Using Probiotics

After consumption, probiotics provide health benefits to the host. Probiotics and their metabolites have therapeutic and nutritional properties that help to alleviate gastrointestinal, neurological, and cardiovascular problems. Probiotics strengthen host immunity through various mechanisms, including improved gut barrier function, receptor site blocking, competitive exclusion of pathogens, and the production of bioactive molecules. Emerging evidence suggests that intestinal bowel diseases can be fatal, but regular probiotic consumption can alleviate disease symptoms. The use and detailed description of the health benefits of probiotics to consumers in terms of reducing intestinal infection, inflammation, and digestive disorders are discussed in this review. The well-designed and controlled studies that examined the use of probiotics to reduce life-threatening activities caused by intestinal bowel diseases are also covered. This review discussed the active principles and potency of probiotics as evidenced by the known effects on host health, in addition to providing information on the mechanism of action.

Probiotics and rifaximin for the prevention of travelers' diarrhea: A systematic review and network meta-analysis

BACKGROUND

Probiotics and rifaximin are treatments for gut microbiota dysbiosis in patients with traveler's diarrhea (TD), and they both proved beneficial for the prevention of TD. However, comparative effectiveness research between them has not been performed. A systematic review and network meta-analysis are to be performed to clarify which of them is more effective in the prevention of TD.

METHODS

Literature concerning the effectiveness of probiotics or rifaximin in the prevention of TD was searched in Medline, Embase, the Cochrane Central Register of Controlled Trials, and clinical registries for randomized controlled trials (RCTs) from inception of these databases to November 30, 2021 without any language restrictions. The primary efficacy outcome was the incidence of TD, and the safety outcome was the incidence of adverse events. The effect size of probiotics was measured by using relative ratio (RR), and the network meta-analysis was performed by using a frequentist approach and a random-effect model.

RESULTS

Totally 17 RCTs after screening 1119 retrieved records were included in analysis and 9 RCTs were with low risk of bias. Compared with placebo, both probiotics and rifaximin were associated with lower incidence of TD (probiotics, RR 0.85, 95% CI 0.76-0.95; rifaximin, RR 0.47, 95% CI 0.35-0.63), and rifaximin was more effective than probiotics (RR 0.56, 95% CI 0.4-0.78). Further analysis showed that sodium butyrate, rifaximin and L. acidophilus + L. bulgaricus + Bifido.bifidum + Strept. Thermophilus were the three most effective treatments for TD.

CONCLUSIONS

Both rifaximin and probiotics are superior over placebo, and rifaximin has better treatment effect than probiotics in reducing the incidence of TD. Different types of probiotics have heterogeneous treatment effects.

Probiotics, their prophylactic and therapeutic applications in human health development: A review of the literature

Antibiotics do not differentiate between good and bad germs, disrupting normal microflora and causing vitamin deficiency in the human body. They also kill healthy bacteria in the gut and genital tract on a large scale, weakening the host's defense mechanism. Probiotics are a colony of bacteria that live in our intestines and are regarded as a metabolic 'organ' due to their beneficial effects on human health, including metabolism and immunological function. They are used in clinical settings to prevent and treat conditions such as diarrhoea, colon cancer, hypertension, diabetes, acute pancreatitis, Helicobacter pylori infection, ventilator-associated pneumonia, migraine and autism. Probiotics may modify immunological activity by increasing innate and adaptive immune responses, altering microbial habitat in the intestine, improving gut barrier function, competitive adherence to the mucosa and epithelium, and producing antimicrobial compounds. The aim of this study is to index that further in depth researches to be conducted on probiotics pivotal role in the prophylaxis and therapeutic usage for a variety of disease that may or may not have treatment alternatives. Key words such as probiotics, microbiota, prophylactics, and therapeutic applications were searched extensively in research databases such as PubMed, PubMed Central (PMC), Scopus, Web of Science, Research Gate, Google Scholar, and Cochrane Library. This concise narrative review article summarized primarily the history, selection, mechanism/mode of action, recent advances in prophylactic and therapeutic applications, and future directions in the use of probiotics for prophylactic and therapeutic applications.

Phenotypic Assessment of Probiotic and Bacteriocinogenic Efficacy of Indigenous LAB Strains from Human Breast Milk

Breast milk is the combination of bioactive compounds and microflora that promote newborn’s proper growth, gut flora, and immunity. Thus, it is always considered the perfect food for newborns. Amongst their bioactives, probiotic communities—especially lactic acid bacteria (LAB)—are characterized from breast milk over the first month of parturition. In this study, seven LAB were characterized phenotypically and genotypically as Levilactobacillus brevis BDUMBT08 (MT673657), L. gastricus BDUMBT09 (MT774596), L. paracasei BDUMBT10 (MT775430), L. brevis BDUMBT11 (MW785062), L. casei BDUMBT12 (MW785063), L. casei BDUMBT13 (MW785178), and Brevibacillus brevis M2403 (MK371781) from human breast milk. Their tolerance to lysozyme, acid, bile, gastric juice, pancreatic juice, and NaCl and potential for mucoadhesion, auto-aggregation, and co-aggregation with pathogens are of great prominence in forecasting their gut colonizing ability. They proved their safety aspects as they were negative for virulence determinants such as hemolysis and biofilm production. Antibiogram of LAB showed their sensitivity to more than 90% of the antibiotics tested. Amongst seven LAB, three isolates (L. brevis BDUMBT08 and BDUMBT11, and L. gatricus BDUMBT09) proved their bacteriocin producing propensity. Although the seven LAB isolates differed in their behavior, their substantial probiotic properties with safety could be taken as promising probiotics for further studies to prove their in vivo effects, such as health benefits, in humans.

Multi-targeted properties of the probiotic saccharomyces cerevisiae CNCM I-3856 against enterotoxigenic escherichia coli (ETEC) H10407 pathogenesis across human gut models

Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of acute traveler's diarrhea. Adhesins and enterotoxins constitute the major ETEC virulence traits. With the dramatic increase in antibiotic resistance, probiotics are considered a wholesome alternative to prevent or treat ETEC infections. Here, we examined the antimicrobial properties of the probiotic Saccharomyces cerevisiae CNCM I-3856 against ETEC H10407 pathogenesis upon co-administration in the TNO gastrointestinal Model (TIM-1), simulating the physicochemical and enzymatic conditions of the human upper digestive tract and preventive treatment in the Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME), integrating microbial populations of the ileum and ascending colon. Interindividual variability was assessed by separate M-SHIME experiments with microbiota from six human individuals. The probiotic did not affect ETEC survival along the digestive tract. However, ETEC pathogenicity was significantly reduced: enterotoxin encoding virulence genes were repressed, especially in the TIM-1 system, and a lower enterotoxin production was noted. M-SHIME experiments revealed that 18-days probiotic treatment stimulate the growth of Bifidobacterium and Lactobacillus in different gut regions (mucosal and luminal, ileum and ascending colon) while a stronger metabolic activity was noted in terms of short-chain fatty acids (acetate, propionate, and butyrate) and ethanol production. Moreover, the probiotic pre-treated microbiota displayed a higher robustness in composition following ETEC challenge compared to the control condition. We thus demonstrated the multi-inhibitory properties of the probiotic S. cerevisiae CNCM I-3856 against ETEC in the overall simulated human digestive tract, regardless of the inherent variability across individuals in the M-SHIME.

Pediatric Digestive Health and the Gut Microbiome: Existing Therapies and a Look to the Future

The human gut is host to trillions of microbes that from birth begin interacting with our immune system. Over time this relationship is thought to shape critical aspects of human function such as metabolism, brain development, immune response, and overall gut health. Recent advances in technology have allowed us to begin understanding this complex relationship and have demonstrated that microbes within the gut ecosystem can be influenced by a variety of factors including mode of delivery, diet, and medication exposure, all of which can impact host health in either positive or detrimental ways. Perturbations of gut homeostasis have been implicated in many forms of digestive disease such as inflammatory bowel disease, irritable bowel syndrome, Helicobacter pylori infection, and even in cases of antibiotic-associated diarrhea. As such, researchers have sought methods to either restore gut homeostasis or prevent dysregulation of the gut community, also known as dysbiosis, through an emerging field known as microbial therapeutics. Examples of existing modalities are reviewed here such as prebiotics, probiotics, fecal microbial transplantation, and dietary therapy. As these therapies become further substantiated through research and increasingly desired by patients and their families, there is a need for providers caring for children to familiarize themselves with the existing data and indications for use. As we look to the future, machine-learning algorithms and more readily available next-generation sequencing of fecal samples may allow us to harness data from a person's gut microbiota to predict response to a particular intervention and tailor therapeutic options with an aim toward precision medicine. [Pediatr Ann. 2021;50(8):e336-e342.].

Gut Microbiota-targeted Interventions for Reducing the Incidence, Duration, and Severity of Respiratory Tract Infections in Healthy Non-elderly Adults

INTRODUCTION

Respiratory tract infections (RTI), such as those caused by influenza viruses and, more recently, the severe acute respiratory syndrome coronavirus-2, pose a significant burden to military health care systems and force readiness. The gut microbiota influences immune function, is malleable, and may provide a target for interventions aiming to reduce RTI burden. This narrative review summarizes existing evidence regarding the effectiveness of probiotics, prebiotics, and synbiotics, all of which are gut microbiota-targeted interventions, for reducing the burden of RTI in military-relevant populations (i.e., healthy non-elderly adults).

MATERIALS AND METHODS

A systematic search strategy was used to identify recent meta-analyses and systematic reviews of randomized controlled trials conducted in healthy non-elderly adults which examined effects of probiotics, prebiotics, or synbiotics on the incidence, duration, and/or severity of RTI, or on immune responses to vaccinations against viruses that cause RTI. Relevant randomized controlled clinical trials not included in those reports were also identified.

RESULTS

Meta-analyses and multiple randomized controlled trials have demonstrated that certain probiotic strains may reduce the incidence, duration, and/or severity of RTI and improve immune responses to vaccination against RTI-causing pathogens in various populations including healthy non-elderly adults. Fewer randomized controlled trials have examined the effects of prebiotics or synbiotics on RTI-related outcomes in healthy non-elderly adults. Nevertheless, some studies conducted within that population and other populations have observed that certain prebiotics and synbiotics reduce the incidence, duration, and/or severity of RTI or improve immune responses to vaccinations against RTI-causing viruses. However, across all product classes, not all product formulations have shown benefit, and most have not been tested in multiple randomized controlled trials in military-relevant populations.

CONCLUSION

Dietary supplementation with certain gut microbiota-targeted interventions, and certain probiotics in particular, may provide viable strategies for reducing RTI-related illness in military personnel. Research in military populations is warranted to fully understand the magnitude of any military health and cost benefits, and to establish definitive recommendations for use.

The effects of probiotics, prebiotics and synbiotics on the reduction of IBD complications, a periodic review during 2009-2020

AIMS

To perform a systematic review on randomized controlled trials to examine the efficacy of probiotics, prebiotics and synbiotics in the treatment of IBD.

METHODS AND RESULTS

PubMed, Web of science, Scopus and Google Scholar were systematically searched from January 2009 to January 2020 using the following keywords: 'Inflammatory Bowel Disease', 'Probiotics' and 'Clinical trial'. The statistical analysis was performed using SPSS software version 24.0. A total of 1832 articles were found during the initial search and 21 clinical trials were eligible. Studies comparing the effects of probiotics and placebo among patients with active ulcerative colitis (UC) showed a significant difference in clinical outcomes. Moreover, probiotics improved the overall induction of remission rates among patients with Crohn's disease (CD). Probiotics significantly decreased the IL-1β, TNF-α and IL-8 levels. Also, the need for systemic steroids, hospitalization, surgery, as well as histological score and disease activity index significantly decreased in patients who used probiotic or pro-/synbiotics.

CONCLUSIONS

The use of probiotics, as food supplements, can induce anti-inflammatory reactions, balance the intestinal homeostasis and induce remission in IBD. The efficacy of probiotics on remission induction is more reported in UC rather than CD. Larger well-designed clinical trials are needed to further determine whether probiotics are of clear benefits for remission in IBD.

Therapeutic, Prophylactic, and Functional Use of Probiotics: A Current Perspective

Probiotics are considered as the twenty-first century panpharmacon due to their competent remedial power to cure from gastrointestinal dysbiosis, systematic metabolic diseases, and genetic impairments up to complicated neurodegenerative disorders. They paved the way for an innovative managing of various severe diseases through palatable food products. The probiotics' role as a "bio-therapy" increased their significance in food and medicine due to many competitive advantages over traditional treatment therapies. Their prophylactic and therapeutic potential has been assessed through hundreds of preclinical and clinical studies. In addition, the food industry employs probiotics as functional and nutraceutical ingredients to enhance the added value of food product in terms of increased health benefits. However, regardless of promising health-boosting effects, the probiotics' efficacy still needs an in-depth understanding of systematic mechanisms and factors supporting the healthy actions.

A successful history: probiotics and their potential as antimicrobials

Introduction: Probiotics are living, non-pathogenic microorganisms (bacteria) that enter through diet in the human body, live during their passage through the gastrointestinal (GI) tract and are beneficial to health. They have become popular in recent years as a way of improving human health through nutrition. This review aims to discuss the efficacy of probiotics for the supportive therapy of certain clinical conditions, especially infectious diseases, as reported in a number of studies, even though some concerns about their safety still remain. Areas covered: This paper will review the history of probiotics, from ancient ages to date, and the evolution of their use in clinical practice. The study is based on both personal professional experience of the authors and a comprehensive literature analysis, including old documents from libraries, searching the related biological and clinical data on Scopus, Web of Science, PubMed, EMBASE, also using the 'cited by' and 'similar articles' options available in PubMed. Expert opinion: Not all researchers agree about the safety and real efficacy of probiotics in common conditions, especially infective diseases. However, the use of probiotics for clinical conditions that may be improved by consumption of these dietary supplements should be considered as a possible supportive therapy in select patients.

Probiotics and prebiotics in clinical tests: an update

Probiotics have been explored in an exponentially increasing number of clinical trials for their health effects. Drawing conclusions from the published literature for the medical practitioner is difficult since rarely more than two clinical trials were conducted with the same probiotic strain against the same medical condition. Consequently, the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) made a few recommendations restricting it to probiotic use against acute gastroenteritis and antibiotic-associated diarrhea. Recent studies also made a strong case for probiotic use against sepsis in preterm and term infants from developing countries. Conclusions on the value of probiotics are best based on detailed meta-analyses (MA) of randomized controlled trials (RCT). Outcomes of MA are discussed in the present review for a number of gastroenterology conditions. Since these MA pool data from trials using different probiotic species, large RCT published sometimes come to different conclusions than MA including these studies. This is not necessarily a contradiction but may only mean that the specific probiotic species did not work under the specified conditions. Positive or negative generalization about probiotics and prebiotics should be avoided. Credible effects are those confirmed in independent trials with a specified probiotic strain or chemically defined prebiotic in a specified patient population under the specified treatment conditions. Even distinct technological preparations of the same probiotic strain might affect clinical outcomes if they alter bacterial surface structures. Underpowered clinical trials are another problem in the probiotic field. Data obtained with sophisticated omics technologies, but derived from less than ten human subjects should be interpreted with caution even when published in high impact journals.

Probiotics: Reiterating What They Are and What They Are Not

It has been over seventeen years since the scientific definition of probiotics was crafted, along with guidelines ensuring the appropriate use of the term. This definition is now used globally, yet on a consistent basis scientists, media and industry misrepresent probiotics or make generalized statements that illustrate a misunderstanding of their utility and limitations. The rate of discovery of novel organisms with potentially therapeutic benefit for both human and environmental health is progressing at an unprecedented rate. However, the term “probiotic” is often misapplied to describe any microbe with plausible therapeutic utility in the human host. It is argued that strict compliance to the scientific definition of the term “probiotic” and avoidance of generalizations to the whole field of probiotics based upon studies of one product, will help advance the development and validation of microbial therapies, and applications to improve human health.

Travelers' Diarrhea: A Clinical Review

BACKGROUND

Travelers' diarrhea is the most common travel-related malady. It affects millions of international travelers to developing countries annually and can significantly disrupt travel plans.

OBJECTIVE

To provide an update on the evaluation, diagnosis, treatment, and prevention of traveler's diarrhea.

METHODS

A PubMed search was completed in Clinical Queries using the key term "traveler's diarrhea". The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. The search was restricted to English literature. Patents were searched using the key term "traveler's diarrhea" from www.freepatentsonline.com.

RESULTS

Between 10% and 40% of travelers develop diarrhea. The attack rate is highest for travelers from a developed country who visit a developing country. Children are at particular risk. Travelers' diarrhea is usually acquired through ingestion of food and water contaminated by feces. Most cases are due to a bacterial pathogen, commonly, Escherichia coli, and occur within the first few days after arrival in a foreign country. Dehydration is the most common complication. Pretravel education on hygiene and on the safe selection of food items is important in minimizing episodes. For mild travelers' diarrhea, the use of antibiotic is not recommended. The use of bismuth subsalicylate or loperamide may be considered. For moderate travelers' diarrhea, antibiotics such as fluoroquinolones, azithromycin, and rifaximin may be used. Loperamide may be considered as monotherapy or adjunctive therapy. For severe travelers' diarrhea, antibiotics such as azithromycin, fluoroquinolones, and rifaximin should be used. Azithromycin can be used even for the treatment of dysentery whereas fluoroquinolones and rifaximin cannot be used for such purpose. Recent patents related to the management of travelers' diarrhea are discussed.

CONCLUSION

Although travelers' diarrhea is usually self-limited, many travelers prefer expedient relief of diarrhea, especially when they are traveling for extended periods by air or ground. Judicious use of an antimotility agent and antimicrobial therapy reduces the duration and severity of diarrhea.