Traveler's Diarrhea

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.

Injuries and medical emergencies among international travellers

BACKGROUND

Tropical infectious diseases and vaccine-preventable emergencies are the mainstay of pre-travel consultations. However, non-communicable diseases, injuries and accidents that occur during travel are not emphasized enough in these settings.

METHODS

We performed a narrative review based on a literature search of PubMed, Google Scholar, UpToDate, DynaMed and LiSSa and on reference textbooks and medical journals dedicated to travel, emergency and wilderness medicine. Relevant secondary references were extracted. We also aimed to discuss newer or neglected issues, such as medical tourism, Coronavirus Disease 2019, exacerbations of co-morbidities associated with international travel, insurance coverage, health care seeking abroad, medical evacuation or repatriation and tips for different types of travellers' emergency medical kits (personal, group, physician handled).

RESULTS

All sources reviewed led to the selection of >170 references. Among epidemiological data on morbidity and deaths while abroad, only retrospective data are available. Deaths are estimated to occur in 1 in 100 000 travellers, with 40% caused by trauma and 60% by diseases, and <3% linked to infectious diseases. Trauma and other injuries acquired during travel, such as traffic accidents and drowning, can be reduced by up to 85% with simple preventive recommendations such as avoiding simultaneous alcohol intake. In-flight emergencies occur on 1 in 604 flights on average. Thrombosis risk is two to three times greater for travellers than for non-travellers. Fever during or after travel can occur in 2-4% of travellers, but in up to 25-30% in tertiary centres. Traveller's diarrhoea, although rarely severe, is the most common disease associated with travel. Autochthonous emergencies (acute appendicitis, ectopic pregnancy, dental abscess) can also occur.

CONCLUSIONS

Pre-travel medicine encounters must include the topic of injuries and medical emergencies, such as the risk-taking behaviours and foster better planning in a comprehensive approach along with vaccines and infectious diseases advices.

Differences in the gut microbiota between Gurkhas and soldiers of British origin

Previous work indicated that the incidence of travellers' diarrhoea (TD) is higher in soldiers of British origin, when compared to soldiers of Nepalese descent (Gurkhas). We hypothesise that the composition of the gut microbiota may be a contributing factor in the risk of developing TD in soldiers of British origin. This study aimed to characterise the gut microbial composition of Gurkha and non-Gurkha soldiers of the British Army. Recruitment of 38 soldiers (n = 22 Gurkhas, n = 16 non-Gurkhas) and subsequent stool collection, enabled shotgun metagenomic sequencing-based analysis of the gut microbiota. The microbiota of Gurkhas had significantly (P < 0.05) lower diversity, for both Shannon and Simpson diversity indices, using species level markers than the gut microbiota of non-Gurkha soldiers. Non-metric Multidimensional Scaling (NMDS) of the Bray-Curtis distance matrix revealed a significant difference in the composition of the gut microbiota between Gurkhas and non-Gurkha soldiers, at both the species level (P = 0.0178) and the genus level (P = 0.0483). We found three genera and eight species that were significantly enriched in the non-Gurkha group and one genus (Haemophilus) and one species (Haemophilus parainfluenzae) which were enriched in the Gurkha group. The difference in the microbiota composition between Gurkha soldiers and soldiers of British origin may contribute to higher colonization resistance against diarrhoeal pathogens in the former group. Our findings may enable further studies into interventions that modulate the gut microbiota of soldiers to prevent TD during deployment.

A systematic review on selection characterization and implementation of probiotics in human health

Probiotics are live bacteria found in food that assist the body's defence mechanisms against pathogens by reconciling the gut microbiota. Probiotics are believed to aid with gut health, the immune system, and brain function, among other factors. They've furthermore been shown to help with constipation, high blood pressure, and skin issues. The global probiotics market has been incrementally growing in recent years, as consumers' demand for healthy diets and wellness has continued to increase. This has prompted the food industry to develop new probiotic-containing food products, as well as researchers to explore their specific characteristics and impacts on human health. Although most probiotics are fastidious microorganisms that are nutritionally demanding and sensitive to environmental conditions, they become less viable as they are processed and stored. In this review we studied the current literature on the fundamental idea of probiotic bacteria, their medical benefits, and their selection, characterization, and implementations.

Graphical Abstract

Interactions of pathogenic Escherichia coli with CEACAMs

The pathogenic Escherichia coli can be parsed into specific variants (pathovars) depending on their phenotypic behavior and/or expression of specific virulence factors. These pathogens are built around chromosomally-encoded core attributes and through acquisition of specific virulence genes that direct their interaction with the host. Engagement of E. coli pathovars with CEACAMs is determined both by core elements common to all E. coli as well as extrachromosomally-encoded pathovar-specific virulence traits, which target amino terminal immunoglobulin variable-like (IgV) regions of CEACAMs. Emerging data suggests that engagement of CEACAMs does not unilaterally benefit the pathogen and that these interactions may also provide an avenue for pathogen elimination.

Impact of international travel and diarrhea on gut microbiome and resistome dynamics

International travel contributes to the global spread of antimicrobial resistance. Travelers' diarrhea exacerbates the risk of acquiring multidrug-resistant organisms and can lead to persistent gastrointestinal disturbance post-travel. However, little is known about the impact of diarrhea on travelers' gut microbiomes, and the dynamics of these changes throughout travel. Here, we assembled a cohort of 159 international students visiting the Andean city of Cusco, Peru and applied next-generation sequencing techniques to 718 longitudinally-collected stool samples. We find that gut microbiome composition changed significantly throughout travel, but taxonomic diversity remained stable. However, diarrhea disrupted this stability and resulted in an increased abundance of antimicrobial resistance genes that can remain high for weeks. We also identified taxa differentially abundant between diarrheal and non-diarrheal samples, which were used to develop a classification model that distinguishes between these disease states. Additionally, we sequenced the genomes of 212 diarrheagenic Escherichia coli isolates and found those from travelers who experienced diarrhea encoded more antimicrobial resistance genes than those who did not. In this work, we find the gut microbiomes of international travelers' are resilient to dysbiosis; however, they are also susceptible to colonization by multidrug-resistant bacteria, a risk that is more pronounced in travelers with diarrhea.

Microbiome–Gut Dissociation in the Neonate: Autism-Related Developmental Brain Disease and the Origin of the Placebo Effect

While the importance of the intestinal microbiome has been realised for a number of years, the significance of the phrase microbiota–gut–brain axis is only just beginning to be fully appreciated. Our recent work has focused on the microbiome as if it were a single entity, modifying the expression of the genetic inheritance of the individual by the generation of interkingdom signalling molecules, semiochemicals, such as dopamine. In our view, the purpose of the microbiome is to convey information about the microbial environment of the mother so as to calibrate the immune system of the new-born, giving it the ability to distinguish harmful pathogens from the harmless antigens of pollen, for example, or to help distinguish self from non-self. In turn, this requires the partition of nutrition between the adult and its microbiome to ensure that both entities remain viable until the process of reproduction. Accordingly, the failure of a degraded microbiome to interact with the developing gut of the neonate leads to failure of this partition in the adult: to low faecal energy excretion, excessive fat storage, and concomitant problems with the immune system. Similarly, a weakened gut–brain axis distorts interoceptive input to the brain, increasing the risk of psychiatric diseases such as autism. These effects account for David Barker’s 1990 suggestion of “the fetal and infant origins of adult disease”, including schizophrenia, and David Strachan’s 1989 observation of childhood immune system diseases, such as hay fever and asthma. The industrialisation of modern life is increasing the intensity and scale of these physical and psychiatric diseases and it seems likely that subclinical heavy metal poisoning of the microbiome contributes to these problems. Finally, the recent observation of Harald Brüssow, that reported intestinal bacterial composition does not adequately reflect the patterns of disease, would be accounted for if microbial eukaryotes were the key determinant of microbiome effectiveness. In this view, the relative success of “probiotic” bacteria is due to their temporary immune system activation of the gut–brain axis, in turn suggesting a potential mechanism for the placebo effect.

Incidence Rate and Risk Factors Associated with Travelers' Diarrhea in International Travelers Departing from Utah, USA

Despite knowledge on the causes and prevention strategies for travelers' diarrhea (TD), it continues to be one of the most common illnesses experienced by U.S. international travelers. However, studies of risk factors associated with TD among U.S. travelers are limited. In this study, we aimed to determine the incidence rate of TD, the proportion of travelers who experience TD, and to identify risk factors associated with TD. In this cross-sectional study, we collected and analyzed data from anonymous posttravel questionnaires submitted by international travelers recruited during their pretravel visit at two travel clinics in Salt Lake City, Utah, from October 2016 to March 2020. Of 571 travelers who completed posttravel surveys, 484 (85%) answered the TD question, of which 111 (23%) reported TD, for an incidence rate of 1.1 episodes per 100 travel-days (95% confidence interval [CI]: 0.9-1.4). In a multivariable model, visiting Southeast Asian (odds ratio [OR]: 2.60; 95% CI: 1.45-4.72) and African (OR: 2.06; 95% CI: 1.09-3.93]) WHO regions, having 10 or more individuals in the group (OR: 3.91; 95% CI: 1.50-11.32]), longer trip duration (OR: 1.01; 95% CI: 1.00-1.02), visiting both urban and rural destinations (OR: 1.94; 95% CI: 1.01-3.90), and taking medications/supplements to prevent TD (OR: 2.74; 95% CI: 1.69-4.47) were statistically significantly associated with increased odds of reporting TD. TD continues to be common in international travelers from the United States. Our findings provide insights regarding travelers' behaviors regarding TD in international travelers from high-income countries and shows the need for additional research into prevention strategies for travelers' diarrhea.

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.

Feeding Our Microbiota: Stimulation of the Immune/Semiochemical System and the Potential Amelioration of Non-Communicable Diseases

Non-communicable diseases are those conditions to which causative infectious agents cannot readily be assigned. It is increasingly likely that at least some of these conditions are due to the breakdown of the previously mutualistic intestinal microbiota under the influence of a polluted, biocide-rich, environment. Following the mid-20th century African studies of Denis Burkitt, the environmental cause of conditions such as obesity has been ascribed to the absence of sufficient fibre in the modern diet, however in itself that is insufficient to explain the parallel rise of problems with both the immune system and of mental health. Conversely, Burkitt himself noted that the Maasai, a cattle herding people, remained healthy even with their relatively low intake of dietary fibre. Interestingly, however, Burkitt also emphasised that levels of non-communicable disease within a population rose as faecal weight decreased significantly, to about one third of the levels found in healthy populations. Accordingly, a more cogent explanation for all the available facts is that the fully functioning, adequately diverse microbiome, communicating through what has been termed the microbiota–gut–brain axis, helps to control the passage of food through the digestive tract to provide itself with the nutrition it needs. The method of communication is via the production of semiochemicals, interkingdom signalling molecules, potentially including dopamine. In turn, the microbiome aids the immune system of both adult and, most importantly, the neonate. In this article we consider the role of probiotics and prebiotics, including fermented foods and dietary fibre, in the stimulation of the immune system and of semiochemical production in the gut lumen. Finally, we reprise our suggestion of an ingestible sensor, calibrated to the detection of such semiochemicals, to assess both the effectiveness of individual microbiomes and methods of amelioration of the associated non-communicable diseases.

Low Dose of Deoxynivalenol Aggravates Intestinal Inflammation and Barrier Dysfunction Induced by Enterotoxigenic Escherichia coli Infection through Activating Macroautophagy/NLRP3 Inflammasomes

The toxicity of deoxynivalenol (DON) in healthy humans and animals has been extensively studied. However, whether the natural-low-dose DON is scatheless under unhealthy conditions, especially intestinal injury, is unknown. Infection of enterotoxigenic Escherichia coli (ETEC) is a classical intestinal injury model. In this study, we explored the effects of low-dose DON on intestinal injury induced by the ETEC infection and the underlying mechanism in piglets, mice, and IPEC-J2 monolayer cells. Results showed that significant growth slowdown, severe diarrhea, and intestinal damage, bacterial multiplication, and translocation were observed in the experimental group (low-dose DON, 0.75 mg/kg in feed for piglets, and 1 mg/kg body weight for mice, combined with the ETEC infection). Meanwhile, more aggressive intestinal inflammation and barrier dysfunction were observed in animals and IPEC-J2 monolayer cells. Higher expression levels of NLRP3 inflammasome and LC3B were observed in jejunum and IPEC-J2 in the experimental group. After treatment with NLRP3 or caspase1 inhibitors, excessive intestinal inflammation rather than barrier dysfunction in the experimental group was limited. CRISPR-Cas9-mediated knockout of LC3B alleviated intestinal inflammation and barrier dysfunction and also inhibited NLRP3 inflammasome. In conclusion, a low dose of DON aggravates intestinal inflammation and barrier dysfunction induced by the ETEC infection by activating macroautophagy and NLRP3 inflammasome.

What's new in travellers' diarrhoea: updates on epidemiology, diagnostics, treatment and long-term consequences

BACKGROUND

Travellers' diarrhoea (TD) is the most common clinical syndrome affecting travellers. This narrative review summarizes key discoveries reported in the last two years related to TD and suggests areas for future research.

METHODS

A PubMed literature search was conducted for novel data in TD research published between 12 January 2018 and 12 January 2020. Inclusion was based on contribution to epidemiology, aetiology, diagnostics, management and long-term consequences and relevance to public health, discovery and clinical practice.

RESULTS

The initial literature search yielded 118 articles. We retrieved 72 and reviewed 31 articles for inclusion. The findings support our understanding that TD incidence varies by traveller group and environment with students and military-travel remaining moderately high risk, and control of food and water in mass gathering events remain an important goal. The growth of culture-independent testing has led to a continued detection of previously known pathogens, but also an increased detection frequency of norovirus. Another consequence is the increase in multi-pathogen infections, which require consideration of clinical, epidemiological and diagnostic data. Fluoroquinolone resistant rates continue to rise. New data on non-absorbable antibiotics continue to emerge, offering a potential alternative to current recommendations (azithromycin and fluoroquinolones), but are not recommended for febrile diarrhoea or dysentery or regions/itineraries where invasive pathogens are likely to cause illness. Recent studies investigated the interaction of the microbiome in TD prevention and consequences, and while discriminating features were identified, much uncertainty remains. The prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) acquisition and carriage is increasing. Finally, continued research documents the post-infectious consequences, whereas mechanisms of reactive arthritis and post-infectious IBS necessitate further investigation.

CONCLUSIONS

Globally, TD remains an important travel health issue and advances in our understanding continue. More research is needed to mitigate risk factors where possible and develop risk-based management strategies to reduce antibiotic usage and its attendant consequences.

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.

Identification and Management of Traveler's Diarrhea

Traveler's diarrhea (TD) is a common occurrence when people travel to foreign countries and can affect individuals of all ages, including those who are pregnant. This clinical syndrome is caused by a variety of intestinal pathogens, and treatment is based on the acuity of the patient's symptoms. This case report describes the clinical presentation and management of a pregnant woman with a history of TD who requests an antibiotic prescription for the potential need of empiric self-treatment of TD for an upcoming business trip outside of the United States. The clinical presentation of TD, differential diagnoses, treatment plan options, prevention recommendations, and empiric self-treatment are reviewed. Current evidence-based guidelines are discussed, and high-risk conditions such as pregnancy are considered.

In vitro antimicrobial activity of Millettia laurentii De Wild and Lophira alata Banks ex C. F. Gaertn on selected foodborne pathogens associated to gastroenteritis

This study aimed at evaluating the antimicrobial potential of aqueous, ethanolic and methanolic extracts of two Cameroonian plants against selected foodborne pathogens. Bioactive compounds were extracted from Millettia laurentii De Wild seeds and Lophira alata Banks ex. C. F. Gaertn leaves using distilled water, ethanol and methanol as solvents. The extracts were tested against Escherichia coli O157, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, Moraxella morganii, Salmonella enteritidis, Klebsiella pneumoniae and Listeria monocytogenes using the microdilution method. The results showed that distilled water extracted a more important mass of phytochemical compounds (18.0–24.60%) compared to ethanol (4.80–5.0%) and methanol (4.20–4.60%). All the extracts exhibited significant antimicrobial activity with MIC values ranging from 5 to 20 μg/mL for M. laurentii seeds extracts and from 1.0 to 20 μg/mL for L. alata leaves extracts. The different plant extracts were ten times less active than gentamicin. The most active extracts were obtained using ethanol as solvent and K. pneumoniae was the most resistant pathogen to all extracts (MBC>20 μg/mL). M. laurentii extracts were bactericidal against L. monocytogenes and P. mirabilis while the reference antibiotic (gentamicin) was bacteriostatic against these pathogens. The results obtained from this study suggest the studied local plant materials as a source of antimicrobial compounds which can be valorized in the medical field as substitute of antibiotics for which many microorganisms have nowadays developed resistance mechanisms. Further studies need to be performed in order to characterize and identify these antimicrobial active molecules.

Is There a Role for Bismuth in Diarrhea Management?

Diarrhea, an illness of both the developed and developing world, involves the burdensome characteristics of frequent bowel movements, loose stools, and abdominal discomfort. Diarrhea is a long-standing challenge in palliative care and can have a myriad of causes, making symptomatic treatment pertinent when illness evaluation is ongoing, when there is no definitive treatment approach, or when effective treatment cannot be attained. Symptomatic therapy is a common approach in palliative care settings. Bismuth is a suitable agent for symptomatic therapy and can be effectively employed for management of chronic diarrhea. The objective of this narrative review is to examine the role of bismuth in management of diarrheal symptoms. To explore this, PubMed (including Medline) and Embase were used to search the existing literature on bismuth and diarrhea published from 1980 to 2019. It was found that bismuth has potential utility for diarrheal relief in multiple settings, including microscopic colitis, traveler's diarrhea, gastrointestinal infection, cancer, and chemotherapy. It also has great potential for use in palliative care patients, due to its minimal side effects. Overall, the antisecretory, anti-inflammatory, and antibacterial properties of bismuth make it a suitable therapy for symptomatic treatment of diarrhea. The limited range of adverse side effects makes it an appealing option for patients with numerous comorbidities. Healthcare providers can explore bismuth as an adjunct therapy for diarrhea management in an array of conditions, especially in the palliative care setting.

Patterns of diseases in health students abroad: A systematic review

BACKGROUND

Different health risks are associated with international electives among medical students, including the transmission of infectious diseases and non-communicable diseases. This review aims to summarise the evidence for illnesses associated with travel in medical students taking part in electives abroad.

METHODS

Articles were identified through a literature search in two databases (until 30 July 2020) - PubMed and Web of Science.

RESULTS

Sixteen articles were included in the systematic review. The results were classified into two broad categories: communicable diseases and non-communicable diseases. Gastrointestinal infections including travellers' diarrhoea were the most common infectious diseases reported by medical students abroad, followed by respiratory tract infections and skin infections. Blood-borne and sexually transmitted infection and systemic febrile infections due to vector-borne pathogens were rarely reported. Only six of the 16 studies addressed microbial carriage. The acquisition of resistant bacteria appeared to be frequent. Traffic accidents and mental health problems were also reported.

CONCLUSIONS

One of the lessons learned from this review is the requirement for large-scale epidemiological studies to evaluate the burden of infectious diseases such as gastrointestinal, respiratory and blood-borne infections with microbiological documentation. In particular, the emergence of the acquisition of resistant bacteria may lead to a theoretical risk of spread to the community and hospitals. Studies addressing mental health issues in the context of medical electives abroad are also needed.

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.

Saccharomyces boulardii CNCM I-745: A Non-bacterial Microorganism Used as Probiotic Agent in Supporting Treatment of Selected Diseases

The yeast Saccharomyces boulardii CNCM I-745 is a unique, non-bacterial microorganism classified as a probiotic agent. In this review article, at first, we briefly summarized the mechanisms responsible for its probiotic properties, e.g. adhesion to and elimination of enteropathogenic microorganisms and their toxins; extracellular cleavage of pathogens’ virulent factors; trophic and anti-inflammatory effects on the intestinal mucosa. The efficacy of S. boulardii administration was tested in variety of human diseases. We discussed the results of S. boulardii CNCM I-745 use in the treatment or prevention of Helicobacter pylori infections, diarrhoea (Clostridium difficile infections, antibiotic-associated diarrhoea, and traveller’s diarrhoea), inflammatory bowel diseases, irritable bowel syndrome, candidiasis, dyslipidemia, and small intestine bacterial overgrowth in patients with multiple sclerosis. In case of limited number of studies regarding this strain, we also presented studies demonstrating properties and efficacy of other strains of S. boulardii. Administration of S. boulardii CNCMI I-745 during antibiotic therapy has certain advantage over bacterial probiotics, because—due to its fungal natural properties—it is intrinsically resistant to the antibiotics and cannot promote the spread of antimicrobial resistance. Even though cases of fungemia following S. boulardii CNCM I-745 administration were reported, it should be treated as a widely available and safe probiotic strain.

Colloidal Silicon Dioxide in Tablet form (Carbowhite) Efficacy in Patients with Acute Diarrhea: Results of Randomized, Double-Blind, Placebo-Controlled, Multi-Center Study

The acute diarrhea is a wide-spread disease. The prescription of enterosorbents is appropriate as a primary measure for the treatment of the acute diarrhea for effective prevention of the fluid and electrolyte loss, as well as method for symptom relief of the attack of the disease. Aim of the study - the antidiarrheal efficacy and safety study of high-dispersion silicon dioxide enterosorbent in tablet dosage form in patients with acute diarrhea. This was randomized, double-blind, placebo-controlled, 4-center study. Acute diarrhea was defined as three and more episodes of watery stool per day either during 48 hours or less before study entry in the patients having normal stool recently. It has been postulated that symptoms and signs of acute diarrhea have to be caused by direct infection of the gastrointestinal tract and did not associated with moderate-to-severe systemic states. 144 patients with established acute diarrhea were randomized into treatment group (enterosorbent "Carbowhite", n = 120) or placebo group. Date collection including severity diarrhea, systemic symptoms was performed at baseline and daily during 7 days. Stool examination and serological assay were performed at baseline. The primary end points were declared as time to complete recovery from acute diarrhea. It has been found that the use of the siliceous enterosorbent ("Carbowhite") allowed to reduce (p < 0.001) the treatment period averagely for 0.9 days (95% confidence interval 0.5-1.2 days) in comparison with placebo. Data of safety monitoring has revealed that both patient groups had negative stool culture, while initiation of antibiotic treatment was run more frequently in placebo group (8.3%) compared to investigational product group (4.1%, P = 0.044). The siliceous enterosorbent "Carbowhite" was well tolerated and reduced the recovery time of the acute episode of the diarrhea in the clinically significant form.

The lupus patient traveller: a guide to the rheumatologist

With an increasing number of international journeys occurring daily, there is also an increase in the need for appropriate medical advice for patients who will undertake such travel. In this context, the lupus patient presents a great challenge to the rheumatologist. However, the demand for such information by patients is low, and it has proven difficult for the medical community to adequately provide it. In this article, we carried out a literature review of the medical recommendations made for the lupus patient in order to guide the rheumatologist through the topic of travel medicine.

Travelers' Diarrhea in Thailand: A Quantitative Analysis Using TaqMan® Array Card

Background

Travelers' diarrhea (TD) is a common illness experienced by travelers from developed countries who visit developing countries. Recent questionnaire-based surveillance studies showed that approximately 6%-16% of travelers experienced TD while visiting Thailand; however, a majority of TD information was limited mainly to US military populations.

Methods

A TD surveillance study was conducted at Bumrungrad International Hospital in 2012-2014 in Bangkok, Thailand. Enteropathogens were identified using conventional methods and the TaqMan® array card (TAC), which uses real-time polymerase chain reaction for the simultaneous detection of multiple pathogens. Analyses to determine pathogen-disease and symptoms association were performed to elucidate the clinical relevance of each enteropathogen.

Results

TAC identified more pathogens per sample than conventional methods. Campylobacter spp. were the most prevalent, followed by the diarrheagenic Escherichia coli and norovirus GII. These agents had significant pathogen-disease associations as well as high attributable fractions among diarrheal cases. A wide range of pathogen loads for Campylobacter spp. was associated with TD, while heat-labile toxin enterotoxigenic Escherichia coli was associated with an increased pathogen load. Most cases were associated with inflammatory diarrhea, while Campylobacter spp. and Shigella spp. were associated with dysentery.

Conclusions

A pan-molecular diagnostic method such as TAC produces quantifiable and comparable results of all tested pathogens, thereby reducing the variability associated with multiple conventional methods. This allows better determination of the clinical relevance of each diarrhea etiologic agent, as well as their geographical relevance in Thailand.

Traveler's diarrhea in children: New insights and existing gaps

The number of children accompanying their parents in international travel is increasing steadily, and with the rising global migration, children more frequently accompany their parents or caregivers for visiting friends or relatives (VFR). As compared to travel for tourism, VFR children are at higher risk of acquiring local diseases, as they more often stay in rural areas in resource-poor locations, have longer periods of visit, are less likely to attend pre-travel consultations, and less frequently adhere to recommended precautions. Travelers's diarrhea (TD) is the most common travel-associated illnesses in children. This review updates the existing knowledge on TD in children, regarding its distinctive epidemiology, risk factors, preventive measures, clinical manifestations, complications, causative microorganisms and management. Despite the limited focused research on pediatric TD, which challenges the formulation of children-oriented evidence-based guidelines, practical recommendations are suggested.

Impact of pre-travel consultation on clinical management and outcomes of travelers' diarrhea: a retrospective cohort study

Background

International travelers are at high risk of acquiring travelers’ diarrhea. Pre-travel consultation has been associated with lower rates of malaria, hepatitis, and human immunodeficiency virus (HIV) infections. The objective was to study the impact of pre-travel consultation on clinical management and outcomes of travelers’ diarrhea.

Methods

This retrospective cohort study analyzed 1160 patients diagnosed with travelers’ diarrhea at Mayo Clinic Rochester, MN from 1994 to 2017. Variables included high-risk activities, post-travel care utilization, antimicrobial prescriptions, hospitalizations, and complications. Travelers were divided into those who sought (n = 256) and did not seek (n = 904) pre-travel consultation. The two groups were compared using the Wilcoxon test for continuous variables and chi-square test for categorical variables. Multivariate logistic regression was used to adjust for differences in traveler characteristics.

Results

More pre-travel consultation recipients were young Caucasians who had more post-travel infectious disease (ID) consultation [OR 3.1 (95% CI 1.9–5.3)], more stool sampling [OR 1.6 (95% CI 1.1–2.4)], and more antimicrobial prescriptions [OR 1.6 (95% CI 1.1–2.5)] for travelers’ diarrhea compared to the non-pre-travel consultation group. The pre-travel consultation group had shorter hospital stays (mean 1.8 days for pre-travel versus 3.3 days for non-pre-travel consultation group, p = 0.006) and reduced gastroenterology consultation rates [OR 0.4 (95% CI 0.2–0.9)]. 23 patients with positive stool cultures had Campylobacter susceptibilities performed; 65% (15/23) demonstrated intermediate susceptibility or resistance to ciprofloxacin.

Conclusion

Pre-travel consultation was associated with higher rates of stool testing and antimicrobial prescriptions. The high rate of quinolone-resistant Campylobacter in our small sample suggests the need for judicious antimicrobial utilization. The pre-travel consultation group did have a shorter duration of hospitalization and reduced need for gastroenterology consultation for prolonged or severe symptoms, which are positive outcomes that reflect reduced morbidity of travelers’ diarrhea.

A review of antibiotic prophylaxis for traveler's diarrhea: past to present

As there is rapid increase in international travel to tropical and subtropical countries, there will likely be more people exposed to diarrheal pathogens in these moderate to high risk areas and subsequent increased concern for traveler’s diarrhea. The disease may appear as a mild clinical syndrome, yet a more debilitating presentation can lead to itinerary changes and hospitalization. As bacterial etiologies are the most common causative agents of TD, the use of antibiotic prophylaxis to prevent TD has been reported among travelers for several years. The most common type of antibiotic used for TD has changed over 50 years, depending on many influencing factors. The use of antibiotic prophylaxis for TD prevention in travelers is still controversial, mainly because of difficulties balancing the risks and benefits. Many factors, such as emerging drug resistance, side effects, cost and risk behavior need to be considered. This article aims to review antibiotic prophylaxis from the 1950s to 2000s, to describe the trend and reasons for different antibiotic use in each decade. We conclude that prophylactic antibiotics should be restricted to some high-risk travelers or short-term critical trips.

Occurrence of 44 elements in human cord blood and their association with growth indicators in newborns

There is growing concern about environmental pollution produced by elements, including "emerging" contaminants, such as rare earth elements (REE) and other trace elements (TE), which are extensively and increasingly employed in the manufacture of consumer electronics. Previous research has shown that prenatal exposure to some elements (mainly heavy metals) may be associated with decreased fetal growth and other adverse birth outcomes. Recent studies have also shown that environmental exposure to REE and TE may be related to adverse effects on human health. This cross-sectional study, which included nearly 92% of the births in 2016 in La Palma (Canary Islands, Spain; n = 471), aimed to evaluate the potential adverse health effects exerted by a wide range of elements on newborns. We quantified the levels of 44 elements (including 26 REE and TE) in their umbilical cord blood. Our results showed low or very low levels of most elements. We found an inverse association between antimony (Sb) and birth weight (Spearman's r = -0.106, p = 0.021). A similar trend was observed between nickel (Ni) and birth weight and between chromium (Cr) and birth length, although in this case the significance was borderline. Bismuth appeared as a risk factor for having a birth weight below the tenth percentile in the univariate (OR = 3.30; 95% CI = 1.25-8.78; p = 0.017) and multivariate analyses (OR = 5.20; 95% CI = 1.29-20.91; p = 0.020). When assessing the effect of element mixtures, the sum of Cr, Ni, and Sb appeared as a risk factor for having a birth weight below the tenth percentile in the univariate (OR = 2.41; 95% CI = 1.08-5.35; p = 0.031) and multivariate analyses (OR = 3.84; 95% CI = 1.42-10.39; p = 0.008). Our findings suggest that some inorganic elements-isolated or in mixture-are associated to a lower fetal growth. Additional research is needed to understand the role of inorganic pollutants on fetal development.

Gastrointestinal Prophylaxis in Sports Medicine

Context:

Because sports participation at all levels often requires international travel, coaches, athletic trainers, and team physicians must effectively protect athletes from gastrointestinal infections. Traveler’s diarrhea is the most common travel-related illness and can significantly interfere with training and performance.

Evidence Acquisition:

A review of relevant publications was completed using PubMed and Google Scholar.

Study Design:

Clinical review.

Level of Evidence:

Level 5

Results:

Enterotoxigenic and enteroaggregative Escherichia coli are the most common bacterial causes of traveler’s diarrhea. Traveler’s diarrhea generally occurs within 4 days of arrival, and symptoms tend to resolve within 5 days of onset. There are several prophylactic agents that physicians can recommend to athletes, including antibiotics, bismuth subsalicylate, and probiotics; however, each has its own unique limitations. Decision-making should be based on the athlete’s destination, length of stay, and intent of travel.

Conclusion:

Prophylaxis with antibiotics is highly effective; however, physicians should be hesitant to prescribe medication due to the side effects and risks for creating antibiotic-resistant bacterial strains. Antibiotics may be indicated for high-risk groups, such as those with a baseline disease or travelers who have little flexible time. Since most cases of traveler’s diarrhea are caused by food and/or water contamination, all athletes should be educated on the appropriate food and water consumption safety measures prior to travel.

Antibiotic treatment of acute gastroenteritis in children

Antibiotic therapy is not necessary for acute diarrhea in children, as rehydration is the key treatment and symptoms resolve generally without specific therapy. Searching for the etiology of gastroenteritis is not usually needed; however, it may be necessary if antimicrobial treatment is considered. The latter is left to the physician evaluation in the absence of clear indications. Antimicrobial treatment should be considered in severely sick children, in those who have chronic conditions or specific risk factors or in specific settings. Traveler’s diarrhea, prolonged diarrhea, and antibiotic-associated diarrhea may also require antibiotic therapy. Depending on the severity of symptoms or based on risk of spreading, empiric therapy may be started while awaiting the results of microbiological investigations. The choice of antibiotic depends on suspected agents, host conditions, and local epidemiology. In most cases, empiric therapy should be started while awaiting such results. Empiric therapy may be started with oral co-trimoxazole or metronidazole, but in severe cases parenteral treatment with ceftriaxone or ciprofloxacin might be considered.

Navigating the jungles of tropical infectious gastrointestinal pathology: a pattern-based approach to the endoscopic biopsy

International travels and global human migration have had the unforeseen consequence of increasing the exposure of histopathologists in developed countries to the pathology of tropical infectious disease. The gastrointestinal tract (GIT) is often the primary site of infection due to the faecal-oral route of transmission and the high risk of exposure to contaminated water, food or soil when travelling to these regions. Whilst current microbiologic techniques are far more sensitive than histology in detecting infectious pathogens, the histopathologist nonetheless retains a pivotal role in diagnosing tropical GIT disease. This role entails evaluating endoscopic biopsies for any characteristic inflammatory pattern, identifying pathogens which may be present and excluding other look-alike pathologies. Recent advances in commercially available diagnostic modalities, including molecular techniques, have further broadened the scope of the histopathologist's armamentarium. This review outlines a practical pattern-based approach to diagnosing tropical GIT infections in endoscopic material, so as to assist pathologists less familiar with this spectrum of pathology.

Vaccines Against Escherichia coli

Escherichia coli has a complex and versatile nature and continuously evolves from non-virulent isolates to highly pathogenic strains causing severe diseases and outbreaks. Broadly protective vaccines against pathogenic E. coli are not available and the rising in both, multi-drug resistant and hypervirulent isolates, raise concern for healthcare and require continuous efforts in epidemiologic surveillance and disease monitoring. The evolving knowledge on E. coli pathogenesis mechanisms and on the mediated immune response following infection or vaccination, together with advances in the "omics" technologies, is opening new perspectives toward the design and development of effective and innovative E. coli vaccines.

International travelers receiving pharmacological immunosuppression: Challenges and opportunities

There is an increasing number of international travelers receiving immunosuppressive therapy due to the better life expectation and quality offered by this kind of treatment. The complexity of pre-travel counseling in these patients lies in their greater susceptibility to certain travel-related infections and the potential severity of these, as well as in the contraindications and interactions that may occur between certain vaccines and/or prophylaxis and their base therapy. Counseling the traveler represents a challenge for clinicians who have to tailor vaccinations and other recommended preventive measures to the immunosuppressed patients. Thus, pre-travel assessment of patients receiving immunosuppressive therapy should be performed in a specialized Traveler's Medical Unit, working closely with the specialist doctor in charge of treating the patient's underlying medical condition. The purpose of this article is to review available evidence on the health recommendations indicated in the pre-travel administration of vaccines, antimalarial chemoprophylaxis and other measures to prevent communicable diseases in travelers receiving immunosuppressive therapy.

Can a galacto-oligosaccharide reduce the risk of traveller's diarrhoea? A placebo-controlled, randomized, double-blind study

BACKGROUND

Diarrhoea is a common medical problem affecting travellers to Asia, Africa and Latin America. The use of prophylactic antimicrobial agents may increase the risk of contracting resistant bacteria. Findings indicate that oligosaccharides, i.e. carbohydrate chains of 3-10 monosaccharides, reduce the risk of diarrhoea.

METHODS

We performed a placebo-controlled, double-blind study of a galacto-oligosaccharide, B-GOS (Bimuno®, Clasado Ltd, Milton Keynes UK), vs placebo for participants travelling to countries with a high/intermediate risk of diarrhoea for 7-15 days. The participants ingested 2.7g of B-GOS daily from 5 days prior to departure throughout the travel period, and returned a questionnaire, with a diarrhoea log, after their return. The case definition of diarrhoea was three or more loose stools per day.

RESULTS

Of 523 enrolled subjects, 334 travellers managed to comply per protocol (PP), 349 followed the protocol at least until the onset of diarrhoea (conditionally evaluable, CE), and 408 followed the protocol with fewer than 5 days of deviance from the protocol (intention to treat, ITT). There was a significant reduction of diarrhoea incidence in the PP group (odds ratio = 0.56, P  =   0.03), while the effect in the CE group was non-significant (OR = 0.65, P  =   0.08). No significant effect was found during the first 7 days after starting with B-GOS, but from day 8 there was a significant effect in both the PP and CE groups (OR = 0.47, P  =   0.02 and OR = 0.53, P  =   0.03, respectively). The entire effect was seen in 1-day (i.e. self-limiting) diarrhoea (PP: OR = 0.25, P  =   0.004). There was no effect on duration or the number of bowel movements during diarrhoea. The severity of diarrhoea was not affected.

CONCLUSIONS

B-GOS reduces the risk of diarrhoea lasting 1 day. The protection seemed to start after a week of treatment with B-GOS. Strict compliance is crucial. The treatment is environmentally friendly and without adverse effects.

Antibiotic Therapy for Acute Watery Diarrhea and Dysentery

Diarrheal disease affects a large proportion of military personnel deployed to developing countries, resulting in decreased job performance and operational readiness. Travelers' diarrhea is self-limiting and generally resolves within 5 days; however, antibiotic treatment significantly reduces symptom severity and duration of illness. Presently, azithromycin is the preferred first-line antibiotic for the treatment of acute watery diarrhea (single dose 500 mg), as well as for febrile diarrhea and dysentery (single dose 1,000 mg). Levofloxacin and ciprofloxacin are also options for acute watery diarrhea (single dose 500 mg and 750 mg, respectively) and febrile diarrhea/dysentery in areas with high rates of Shigella (500 mg once for 3 days [once daily with levofloxacin and twice daily with ciprofloxacin]), but are becoming less effective because of increasing fluoroquinolone resistance, particularly among Campylobacter spp. Another alternate for acute watery diarrhea is rifaximin (200 mg 3 times per day for 3 days); however, it should not be used with invasive illness. Use of loperamide in combination with antibiotic treatment is also beneficial as it has been shown to further reduce gastrointestinal symptoms and duration of illness. Because of regional differences in the predominance of pathogens and resistance levels, choice of antibiotic should take travel destination into consideration.

Enterotoxigenic Escherichia coli Flagellin Inhibits TNF-Induced NF-κB Activation in Intestinal Epithelial Cells

Enterotoxigenic Escherichia coli (ETEC) causes childhood diarrhea in developing countries. ETEC strains produce the heat-labile enterotoxin (LT) and/or heat-stable enterotoxins (ST) and encode a diverse set of colonization factors used for adherence to intestinal epithelial cells. We previously found that ETEC secretes a heat-stable protein we designated as ETEC Secreted Factor (ESF) that inhibits the extent of NF-κB activation normally induced by tumor necrosis factor alpha (TNF). Here we fractionated ETEC supernatants using fast protein liquid chromatography (FPLC) and determined that ETEC flagellin was necessary and sufficient to protect IκBα from degradation in response to TNF stimulation. These data suggest a potentially novel mechanism by which ETEC may evade the host innate immune response by down-regulating NF-κB-dependent host responses.

Travel During Pregnancy: Considerations for the Obstetric Provider

Importance

Travel among US citizens is becoming increasingly common, and travel during pregnancy is also speculated to be increasingly common. During pregnancy, the obstetric provider may be the first or only clinician approached with questions regarding travel.

Objective

In this review, we discuss the reasons women travel during pregnancy, medical considerations for long-haul air travel, destination-specific medical complications, and precautions for pregnant women to take both before travel and while abroad. To improve the quality of pretravel counseling for patients before or during pregnancy, we have created 2 tools: a guide for assessing the pregnant patient's risk during travel and a pretravel checklist for the obstetric provider.

Evidence Acquisition

A PubMed search for English-language publications about travel during pregnancy was performed using the search terms "travel" and "pregnancy" and was limited to those published since the year 2000. Studies on subtopics were not limited by year of publication.

Results

Eight review articles were identified. Three additional studies that analyzed data from travel clinics were found, and 2 studies reported on the frequency of international travel during pregnancy. Additional publications addressed air travel during pregnancy (10 reviews, 16 studies), high-altitude travel during pregnancy (5 reviews, 5 studies), and destination-specific illnesses in pregnant travelers.

Conclusions and Relevance

Travel during pregnancy including international travel is common. Pregnant travelers have unique travel-related and destination-specific risks. We review those risks and provide tools for obstetric providers to use in counseling pregnant travelers.

[Traveller's diarrhoea]

Traveller's diarrhoea (TD) is acquired primarily through ingestion of food and drinks contaminated with pathogens that cause diarrhoea. They can be bacteria, protozoa, helminths, and viruses. Globally, the most common causes of TD are two pathotypes of Escherichia coli (enterotoxigenic and enteroaggregative) and Campylobacter, although there are significant variations by geographic area visited. Most TD occurs in individuals traveling to low-middle income countries. The type of travel, length of stay, traveller's age, and the presence of certain underlying conditions are important risk factors to consider for the acquisition of TD. While TD is usually a mild and self-limiting disease, half of travellers with TD experience some limitation of activities during their trip, while up to 10% will experience persistent diarrhoea or other complications. The purpose of this article is to provide an updated microbiological, epidemiological, and clinical profile of traveller's diarrhoea, including known risk factors, as well as to make recommendations on the prevention and treatment of TD.