Traveler's Diarrhea Research Articles

Preparation and Evaluation of Sustained Release Tablet of Rifaximin by using Cross linked Sodium Alginate

Rifaximin treats traveler's diarrhea and irritable bowel syndrome by stopping the growth of the bacteria that cause diarrhea. Rifaximin treats hepatic encephalopathy by stopping the growth of bacteria that produce toxins and that may worsen liver disease. The short half life and high frequency of administration of drug makes it a suitable candidate for designing sustained drug delivery system. The aim of the present investigation was to develop a sustained release matrix tablet of Rifaximin using sodium alginate and cross linked sodium alginate and to evaluate the drug release kinetics. In order to achieve the required sustained release profile, the tablets were prepared by a wet granulation method. The formulated tablets were characterized for pre-compression and post-compression parameters and they were in the acceptable limits. The drug release data obtained after an in vitro dissolution study was fitted to various release kinetic models in order to evaluate the release mechanism and kinetics. The criterion for selecting the best fit model was linearity (coefficient of correlation). Drug release mechanism was found to follow a complex mixture of diffusion, swelling and erosion. The dosage form holds the potential to control the release rate of drug and extend the duration of action of a drug.

Management and Prevention of Traveler's Diarrhea: A Cross-Sectional Study on Knowledge, Attitudes, and Practices in Italian Occupational Physicians (2019 and 2022).

Even though Italian Occupational Physicians (OP) are increasingly involved in the managing of overseas workers, their knowledge, attitudes, and practices (KAP) in travel medicine are mostly undefined. We, therefore, permed a KAP study specifically targeting the management of travelers' diarrhea (TD) by OP. A total of 371 professionals (43.4% males; mean age 40.8 ± 10.9 years) completed in 2 rounds (2019 and 2022) a specifically designed web questionnaire that inquired participating OP on their knowledge status (KS), risk perception, and management of TD through pre- and post-travel advice and interventions. Multivariable odds ratios (aOR) for predictors of a better knowledge status were calculated through regression analysis. Eventually, the majority of participants (53.4%) had participated in the management of cases of TD in the previous months, but only 26.4% were reportedly involved in pre-travel consultations. The overall knowledge status was unsatisfying (potential range: 0-100%, actual average of the sample 59.6% ± 14.6), with substantial uncertainties in the management of antimicrobial treatment. Interestingly, only a small subset of participants had previously prescribed antimicrobial prophylaxis or treatment (3.5% and 1.9%, respectively). Main effectors of a better knowledge status were: having a background qualification in Hygiene and Public Health (aOR 14.769, 95%CI 5.582 to 39.073), having previously managed any case of (aOR 3.107, 95%CI 1.484 to 6.506), and having higher concern on TD, reported by acknowledging high frequency (aOR 8.579, 95%CI 3.383 to 21.756) and severity (aOR 3.386; 95%CI 1.741 to 6.585) of this disorder. As the adherence of participating OP to official recommendations for TD management was unsatisfying, continuous Education on Travel Medicine should be improved by sharing up-to-date official recommendations on appropriate treatment options for TD.

Travel‐related gastrointestinal diseases: Assessment and management

AbstractIntroductionGastrointestinal illnesses are among the most common health problems affecting travellers returning from international travel. Its public health implications include economic healthcare costs and the risk of promoting antimicrobial resistance. This narrative review aims to critically appraise the literature concerning gastrointestinal diseases in travellers and outlines a practical approach to aid clinicians in their assessment and management.MethodsThe Medline (PubMed) and SCOPUS databases were searched for articles relating to gastrointestinal issues in returning travellers. Articles were primarily restricted to those published in the last 5 years. Only studies on human subjects were included.ResultsDiarrhoea is the most common gastrointestinal symptom experienced by approximately 40%–60% of travellers, but abdominal pain, bloating and fatigue are also common. DiarrhoeagenicEscherichia colispecies remain the most common cause of travellers’ diarrhoea (TD), with parasitic diseases predominating in those with persistent symptoms. Molecular diagnostic techniques enable highly sensitive simultaneous testing for a multitude of enteropathogens, though more research is required to confirm the pathogenic significance of organisms identified. Further research into poorly absorbable antibiotics and novel therapies such as phage treatment may help to alleviate the burden of antimicrobial resistance. There is a role for empirical anti‐parasitic therapy in selected cases.ConclusionClinicians across a range of medical specialities should be familiar with the presentation, aetiology and management of gastrointestinal illness in the returning traveller. Efforts to improve destination sanitation and hygiene infrastructure may serve to reduce the burden of preventable illness in this setting.

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.

Prevalence of Multidrug-Resistant Diarrheagenic Escherichia coli in Asia: A Systematic Review and Meta-Analysis.

Diarrhea is one of the leading causes of morbidity and mortality in developing countries. Diarrheagenic Escherichia coli (DEC) is an important bacterial agent for diarrhea in infants, children, and international travelers, and accounts for more than 30% of diarrheal cases in children less than 5 years old. However, the choices of antimicrobial agents are now being limited by the ineffectiveness of many first-line drugs, in relation to the emergence of antimicrobial-resistant E. coli strains. The aim of this systematic review and meta-analysis was to provide an updated prevalence of antimicrobial-resistant DEC in Asia. A comprehensive systematic search was conducted on three electronic databases (PubMed, ScienceDirect, and Scopus), where 40 eligible studies published between 2010 and 2022 were identified. Using meta-analysis of proportions and a random-effects model, the pooled prevalence of DEC in Asian diarrheal patients was 22.8% (95% CI: 16.5–29.2). The overall prevalence of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing DEC strains was estimated to be 66.3% (95% CI: 58.9–73.7) and 48.6% (95% CI: 35.1–62.1), respectively. Considering antimicrobial drugs for DEC, the resistance prevalence was highest for the penicillin class of antibiotics, where 80.9% of the DEC isolates were resistant to amoxicillin and 73.5% were resistant to ampicillin. In contrast, resistance to carbapenems such as imipenem (0.1%), ertapenem (2.6%), and meropenem (7.9%) was the lowest. The relatively high prevalence estimation signifies that the multidrug-resistant DEC is a public health threat. Effective antibiotic treatment strategies, which may lead to better outcomes for the control of E. coli infections in Asia, are necessary.

POS-124 Traveler diarrhea in 2 patients, is it Cholera or no Cholera, That is the question

Cholera is gastroenteritis caused by Vibrio cholerae. It presents with vomiting, severe secretory diarrhoea, and dehydration. It presents as watery, rice-water stools with a fishy odour. It can cause severe complications with severe electrolyte imbalances such as hyponatraemia, hypernatraemia, and hypokalaemia and oligoanuric acute kidney injury (AKI) due to acute tubular necrosis (ATN). Case 1: A 19-year-old arrived few days back from Bangladish was admitted with altered mental status, vomiting and diarrhea, His labs on admission showed creatinine 713 micromol/L, urea 21.6 mmol/L, bicarbonate 13 mmol sodium 148 mmol/L, potassium 3.6 mmol/L, chloride 109 mmol/L. WBC 28 x 109, Hb 154 g/L , lactate was normal,urine analysis showed positive leucocyte esterase, negative nitrates, positive blood, WBCs 756 cells/microL, RBCs 12,759 cells/microL, PH 6.5, specific gravity 1.019 with granular casts, procalcitonin 813 ng/dL. Urine albumin was > 400 mg/L. On day 3 of admission creatinine peaked to 1,104 micromol/L, urea 38mmol/L, he became anuric with development of pulmonary edema, he received 2 short sessions of hemodialysis. Stool PCR showed positive Vibrio,Enteroaggregative E.coli (EAEC), Enteropathogenic E.coli (EPEC), Enterotoxigenic E. coli (ETEC) lt/ st, Shigella/ Enteroinvasive E. coli (EIEC) Norovirus, Sapovirus, C.diff, and campylobacter. During hospitalization patient was afebrile and maintained his blood pressure, he received intravenous fluids for resuscitation and completed a course of ceftriaxone, azithromycin and doxycycline. Creatinine on discharge was 110microcol/L, urea 6.4 mmol/L. Case 2: 47 years old male patient previously healthy, arrived from Bangladesh 2 days prior to admission, presented with uncountable episodes of watery diarrhea associated with central abdominal pain, nausea, and vomiting. Patient was severely dehydrated, anuric, labs in ED showed creatinine 456 micromol/L , bicarbonate 11 mmol/L , urea 10.8 mmol/L, no hyperkalemia, Albumin 55g/L ( normal range 32-52), venous PH 7.16, hemoglobin 180 g/L , WBCs 17.7 x109. repeated labs within 12 hours showed worsening acidosis despite starting sodium bicarbonate intravenous boluses and infusion. Venous PH 7.04, patient was initiated on hemodialysis via temporary dialysis line due to refractory worsening acidosis,. Peak creatinine reached 635 micromol/L and bicarbonate 9 mmol/L, protein creatinine ration 2 g/g. He received 2 short session of hemodialysis with aggressive fluid resuscitation, urine output in day was 1.4 L, on day 10 of hospitalization, creatinine continue to improve and reached 94 micromol/L and patient was discharged home. His stool PCR was negative for Campylobacter (jejuni, coli and upsalien ), Clostridium difficile (toxin A/ B), Plesiomonas shigelloides, salmonella, Yersinia enterocolitica,Vibrio (parahaemolyticus, vulnificus, and Vibrio cholerae), EAEC, EPEC, ETEC all were not detected. He completed 1 week course of Ceftriaxone, Metronidazole, and Azithromycin. The cause of his traveler diarrhea was not known but the patient responded well to supportive measures, hemodialysis and antibiotics. Both patients were discharged home with improving renal function. Traveler diarrhea from endemic areas can be due to multiple pathogens. supportive treatment including vigorous hydration and initiation of hemodialysis may be required in sever cases of AKI.

The role of CFA/I in adherence and toxin delivery by ETEC expressing multiple colonization factors in the human enteroid model.

Enterotoxigenic Escherichia coli (ETEC) is a primary causative agent of diarrhea in travelers and young children in low-to-middle-income countries (LMICs). ETEC adhere to intestinal epithelia via colonization factors (CFs) and secrete heat-stable toxin (ST) and/or heat-labile toxin (LT), causing dysregulated cellular ion transport and water secretion. ETEC isolates often harbor genes encoding more than one CF that are targets as vaccine antigens. CFA/I is a major CF that is associated with ETEC that causes moderate-to-severe diarrhea and plays an important role in pathogenesis. The Global Enteric Multicenter Study finding that 78% of CFA/I-expressing ETEC also encode the minor CF CS21 prompted investigation of the combined role of these two CFs. Western blots and electron microscopy demonstrated growth media-dependent and strain-dependent differences in CFA/I and CS21 expression. The critical role of CFA/I in adherence by ETEC strains expressing CFA/I and CS21 was demonstrated using the human enteroid model and a series of CFA/I- and CS21-specific mutants. Furthermore, only anti-CFA/I antibodies inhibited adherence by global ETEC isolates expressing CFA/I and CS21. Delivery of ST and resulting cGMP secretion was measured in supernatants from infected enteroid monolayers, and strain-specific ST delivery and time-dependent cGMP production was observed. Interestingly, cGMP levels were similar across wildtype and CF-deficient strains, reflecting a limitation of this static aerobic infection model. Despite adherence by ETEC and delivery of ST, the enteroid monolayer integrity was not disrupted, as shown by the lack of decrease in transepithelial electrical resistance and the lack of IL-8 cytokines produced during infection. Taken together, these data demonstrate that targeting CFA/I in global clinical CFA/I-CS21 strains is sufficient for adherence inhibition, supporting a vaccine strategy that focuses on blocking major CFs. In addition, the human enteroid model has significant utility for the study of ETEC pathogenesis and evaluation of vaccine-induced functional antibody responses.

Doxycycline as an antimalarial: Impact on travellers’ diarrhoea and doxycycline resistance among various stool bacteria – Prospective study and literature review

BackgroundAntibiotics predispose travellers to acquire multidrug-resistant bacteria, such as extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE). Although widely used in antimalarial prophylaxis, doxycycline has scarcely been studied in this respect. MethodsWe explored the impact of doxycycline on rates of traveller's diarrhoea (TD), ESBL-PE acquisition and, particularly, doxycycline co-resistance among travel-acquired ESBL-PE in a sample of 412 visitors to low- and middle-income countries.We reviewed the literature on traveller studies of doxycycline/tetracycline resistance among stool pathogens and the impact of doxycycline on TD rates, ESBL-PE acquisition, and doxycycline/tetracycline resistance. ResultsThe TD rates were similar for doxycycline users (32/46; 69.6%) and non-users (256/366; 69.9%). Of the 90 travel-acquired ESBL-PE isolates, 84.4% were co-resistant to doxycycline: 100% (11/11) among users and 82.3% (65/79) among non-users.The literature on doxycycline's effect on TD was not conclusive nor did it support a recent decline in doxycycline resistance. Although doxycycline did not increase ESBL-PE acquisition, doxycycline-resistance among stool pathogens proved more frequent for users than non-users. ConclusionsOur prospective data and the literature review together suggest the following: 1) doxycycline does not prevent TD; 2) doxycycline use favours acquisition of doxy/tetracycline-co-resistant intestinal bacteria; 3) although doxycycline does not predispose to travel-related ESBL-PE acquisition per se, it selects ESBL-PE strains co-resistant to doxycycline; 4) doxycycline resistance rates are high among stool bacteria in general with no evidence of any tendency to decrease.

Traveller's diarrhoea: Which pathogens? When, whom and how to treat?

Traveller's diarrhoea: Which pathogens? When, whom and how to treat?

Protocolo de prevención y tratamiento de la diarrea del viajero

The increase in travel to tropical and subtropical areas has caused an increase in imported disease in Western countries. Traveler's diarrhea is one of the main imported diseases. Though normally mild and self-limited, it is the principal cause for a medical consultation after an international trip. It has a big impact on the normal course of the trip. Give that the intake of contaminated food and drinks is the origin of most cases, prevention is the fundamental pillar. Likewise, due to its high incidence, travelers should be advised about the possibility of self-treatment.

International travel and travelers’ diarrhea – Increased risk of urinary tract infection

BackgroundUrinary tract infections (UTIs) rank among the most common infections encountered in health care, with an annual incidence of 12% for women. Despite the vast numbers of international travels (over 1.5 billion annually), no prospective studies have had primary focus on UTIs during travel. MethodsWe recruited in 2008–17 international travelers who all filled out pre- and post-travel questionnaires. Incidence rates of UTI were calculated separately for both sexes. Multivariable analyses were conducted to identify risk factors for UTI during travel. ResultsIn total 15/517 (2,9%) travelers acquired UTI during travel, yielding an annual incidence of 62% for female and 18% for male travelers. Travelers’ diarrhea (TD) was identified as a factor predisposing to UTI (OR 9.2, 95% CI 1.5–+∞, p = 0.011); all UTI cases were recorded by travelers with TD. ConclusionsTo our knowledge, this is the first prospective study with a primary focus on UTI during travel. Our data reveal that among travelers the incidence of UTI far exceeds that reported for the general population. TD was identified as a major risk factor for the infection. Our results suggest TD prevention as a means of also preventing UTI during travel.

Travellers' diarrhoea - prevention, trends and role of microbiome

In this review, we present a contemporary look at the management of travellers' diarrhoea (TD), and we discuss the potential role of a microbiome as well as the administration of live microorganisms in order to prevent TD. We performed a comprehensive search using the PubMed and Web of Science databases for the period 2014-2021, looking for original and review articles on travellers' diarrhoea. TD belongs among the most frequent illnesses experienced by travellers. For the most part, it is manifested as an acute yet self limiting condition, and only in a few cases proceeds to a prolonged form. Epidemiological analyses have shown that the majority of TD cases are caused by bacterial infections. In practice, pharmacological therapy is often used in the prevention and treatment of TD, since patients naturally seek preventive measures against the development of its severe course and its impact on planned activities. Bismuth salicylate is a strongly recommended TD prophylaxis but is not available on all European Union markets. Although the antibiotic prophylaxis is not generally recommended in guidelines, some antibiotic or chemotherapeutic agents are accessible over-the-counter in certain countries, and travellers are routinely encouraged to use them preventively. This routine can alter the microbiome of the traveller and promote the spread of drug resistant bacteria in their place of residence. Probiotic administration is considered safe, although the quality of evidence in favour of its prophylactic use in TD is currently low. The challenge for public health authorities is to educate personnel that can directly influence the behaviour of travellers through safe and effective pharmacological alternatives to antibiotics. Manipulation of the gut microbiome using specific probiotic strains can represent a safe and promising intervention.

Pan-Genome Analysis of Laribacter hongkongensis: Virulence Gene Profiles, Carbohydrate-Active Enzyme Prediction, and Antimicrobial Resistance Characterization.

Laribacter hongkongensis is a new emerging foodborne pathogen that causes community-acquired gastroenteritis and traveler’s diarrhea. However, the genetic features of L. hongkongensis have not yet been properly understood. A total of 45 aquatic animal-associated L. hongkongensis strains isolated from intestinal specimens of frogs and grass carps were subjected to whole-genome sequencing (WGS), along with the genome data of 4 reported human clinical strains, the analysis of virulence genes, carbohydrate-active enzymes, and antimicrobial resistance (AMR) determinants were carried out for comprehensively understanding of this new foodborne pathogen. Human clinical strains were genetically more related to some strains from frogs inferred from phylogenetic trees. The distribution of virulence genes and carbohydrate-active enzymes exhibited different patterns among strains of different sources, reflecting their adaption to different host environments and indicating different potentials to infect humans. Thirty-two AMR genes were detected, susceptibility to 18 clinical used antibiotics including aminoglycoside, chloramphenicol, trimethoprim, and sulfa was checked to evaluate the availability of clinical medicines. Resistance to Rifampicin, Cefazolin, ceftazidime, Ampicillin, and ceftriaxone is prevalent in most strains, resistance to tetracycline, trimethoprim-sulfamethoxazole, ciprofloxacin, and levofloxacin are aggregated in nearly half of frog-derived strains, suggesting that drug resistance of frog-derived strains is more serious, and clinical treatment for L. hongkongensis infection should be more cautious.

Potential of tropical diseases in Germany : Important pathogens in travelers and migrants

Gastrointestinal infections are among the most frequent imported diseases diagnosed in Germany in travelers or migrants from the tropics. Acute traveler's diarrhea is the most frequent illness in long-distance travelers and in high-risk areas (e.g. India, Mexico) around one third of all travelers suffer from diarrhea. Chronic diarrhea plays arole especially after longer stays abroad (> 4weeks) and in migrants and is often caused by protozoa. Helminths are less frequently the causative agent of gastrointestinal complaints (diarrhea, nausea, abdominal pain). Aworm infestation of the large and small intestines is often present but helminths can also affect the liver or lead to generalized symptoms of illness when larvae migrate. In principle, in the case of gastrointestinal complaints after exposure to the tropics, the possibility of an imported tropical endemic infectious disease must be considered and appropriate diagnostics initiated. For travelers returning from tropical countries other, sometimes life-threatening diseases, such as malaria, typhoid fever, rickettsiosis and viral hemorrhagic fever (VHF) can present with gastrointestinal symptoms and should never be overlooked.

Weather variables as important clinical predictors of bacterial diarrhoea among international travellers.

Clinicians and travellers often have limited tools to differentiate bacterial from non-bacterial causes of travellers' diarrhoea (TD). Development of a clinical prediction rule assessing the aetiology of TD may help identify episodes of bacterial diarrhoea and limit inappropriate antibiotic use. We aimed to identify predictors of bacterial diarrhoea among clinical, demographic and weather variables, as well as to develop and cross-validate a parsimonious predictive model. We collected de-identified clinical data from 457 international travellers with acute diarrhoea presenting to two healthcare centres in Nepal and Thailand. We used conventional microbiologic and multiplex molecular methods to identify diarrheal aetiology from stool samples. We used random forest and logistic regression to determine predictors of bacterial diarrhoea. We identified 195 cases of bacterial aetiology, 63 viral, 125 mixed pathogens, 6 protozoal/parasite and 68 cases without a detected pathogen. Random forest regression indicated that the strongest predictors of bacterial over viral or non-detected aetiologies were average location-specific environmental temperature and red blood cell on stool microscopy. In 5-fold cross-validation, the parsimonious model with the highest discriminative performance had an area under the receiver operator curve of 0.73 using 3 variables with calibration intercept -0.01 (standard deviation, SD 0.31) and slope 0.95 (SD 0.36). We identified environmental temperature, a location-specific parameter, as an important predictor of bacterial TD, among traditional patient-specific parameters predictive of aetiology. Future work includes further validation and the development of a clinical decision-support tool to inform appropriate use of antibiotics in TD.

Travel vaccines: what is in the pipeline?

While no vaccine is on the horizon to prevent traveler's diarrhea, progress has been made in the field of malaria and dengue fever. In both cases, the objective is not primarily the prevention among travelers but rather the reduction of morbidity and mortality in populations living in endemic areas. The immune mechanisms protecting against parasitosis are not well understood, which further complicates vaccine development. The fact that veterinary vaccines against the parasites causing cysticercosis and echinococcosis are available for animals, justifies a certain optimism that vaccines against parasitosis will also be available for humans in the future. We report on recent developments in dengue, malaria, schistosomiasis, and hookworm vaccines.

A Brief Overview on Probiotics: The Health Friendly Microbes

Probiotics are defined as non-pathogenic live microorganisms that, when administered in adequate amounts, confer health benefits on the host. Association of probiotics with human beings has a lot of history. Well known as 'health-friendly bacteria', they are widely used commercially as a functional food. The popularity of probiotics has gone exponentially high due to an increasing number of clinical trials, supporting their beneficial effects. Several in vivo and in-vitro experimental evidence supports strain-specific and disease-specific probiotic efficacy to prevent and ameliorate antibiotic-associated diarrhoea, traveller's diarrhoea, ulcerative colitis, and many more. Besides, numerous recent studies have reported that probiotics could have a significant effect in alleviating various metabolic, lifestyle and diet-related disorders like obesity, type 2 diabetes, metabolic syndrome, irritable bowel syndrome Strains of Bifidobacterium, Lactobacillus and Saccharomyces boulardii are the most commonly used as probiotics. Safety, efficacy, pathogenicity, infectivity, intrinsic property, virulence factors are to be addressed during probiotic selection. The underlying mechanisms of probiotics effects are still not fully elucidated and have been under intensive research. Numerous diverse, strain-specific probiotic mechanisms have been proposed, which include early colonization of perturbed microbes, competitive exclusion of pathogens, short-chain volatile fatty acid production, alteration of gut pH, immunomodulation and many more. Considering the remarkable influence on human health, probiotics seem to be alluring attractive agents to promote human health conditions and to improve the quality of life against several diseases. This review discusses the current documentation and recent advances on probiotics and their possible health attributes, in scientific literature, focusing on diverse, heterogeneous, and strain-specific mechanisms of action. Randomised human controlled clinical trials are needed to reconfirm its safety and beneficial effects.

726. Operational Impact of Infectious Disease Threats During Military Travel

BackgroundWe evaluated the incidence and operational impact of travelers’ diarrhea (TD), influenza-like illness (ILI) and undifferentiated febrile illness (FI) in US active duty (AD) personnel traveling outside the continental U.S for deployment (DEP), joint military training exercises (EXR) or other military travel (e.g. Temporary Duty Travel) (TDY). MethodsAD personnel traveling for ≤ 6.5 months were prospectively enrolled between 2010-2019. Participants completed a post-travel survey regarding risk behaviors, illnesses and impact on daily activities. Trip purpose was categorized into DEP, EXR, TDY and syndromic definitions were used to identify cases of TD, ILI and FI based on symptoms. A multivariate logistic regression model with backward selection was used to determine the odds ratio associated with partial or complete incapacitation due to infections (a composite endpoint of either TD, ILI or FI). Results1822 servicemembers were enrolled: 36.2% traveled on DEP, 36.2% for EXR and 27.7% for TDY (Table 1). 83.5% of personnel traveling for DEP were Special Operations and Marine units, and 82% of the EXR group participated in Pacific Pathways. Overall, 19% of US personnel experienced infections associated with partial or complete incapacitation (median duration of incapacitation- TD: 1 day; ILI: 4 days; FI: 3 days). DEP personnel had a longer travel duration and the highest rate of partial or complete incapacitation due to TD, ILI or FI (Figure 1 and 2). Risk factors associated with partial or complete incapacitation due to infections were non-adherence with malaria chemoprophylaxis (OR: 1.7 [95%CI:1.2-2.4]), close contact with locals (OR:1.7 [95%CI:1.3-2.2]), inability to clean hands regularly before meals (OR: 1.7 [95%CI: 1.3-2.3]), fresh water or rodent exposure OR: 1.4 (95%CI:1.1-1.9) and consuming street vendor food (OR:1.8 [95%CI:1.3-2.4]).Table 1. Demographic and travel characteristics of AD personnel traveling outside the continental US. Proportion of AD servicemembers that experienced TD, ILI or undifferentiated febrile illness during DEP, EXR, TDY (p<0.05 for the comparison of each illness between DEP, EXR and TDY).Figure 2. Proportion of AD personnel with partial or complete incapacitation due to TD, ILI or FI during DEP, EXR or TDY (p < 0.05 for the comparison of each illness between DEP, EXR and TDY).ConclusionInfectious disease syndromes are common during overseas military travel. TD had the highest negative impact on military travel especially among DEP personnel. We identified several modifiable risk factors associated with incapacitating infections which can be used to inform preventive and treatment strategies.Disclosures All Authors: No reported disclosures

Genomic Epidemiology and Antimicrobial Susceptibility Profile of Enterotoxigenic Escherichia coli From Outpatients With Diarrhea in Shenzhen, China, 2015–2020

Enterotoxigenic Escherichia coli (ETEC) is the leading cause of severe diarrhea in children and the most common cause of diarrhea in travelers. However, most ETEC infections in Shenzhen, China were from indigenous adults. In this study, we characterized 106 ETEC isolates from indigenous outpatients with diarrhea (77% were adults aged >20 years) in Shenzhen between 2015 and 2020 by whole-genome sequencing and antimicrobial susceptibility testing. Shenzhen ETEC isolates showed a remarkable high diversity, which belonged to four E. coli phylogroups (A: 71%, B1: 13%, E: 10%, and D: 6%) and 15 ETEC lineages, with L11 (25%, O159:H34/O159:H43, ST218/ST3153), novel L2/4 (21%, O6:H16, ST48), and L4 (15%, O25:H16, ST1491) being major lineages. Heat-stable toxin (ST) was most prevalent (76%, STh: 60% STp: 16%), followed by heat-labile toxin (LT, 17%) and ST + LT (7%). One or multiple colonization factors (CFs) were identified in 68 (64%) isolates, with the common CFs being CS21 (48%) and CS6 (34%). Antimicrobial resistance mutation/gene profiles of genomes were concordant with the phenotype testing results of 52 representative isolates, which revealed high resistance rate to nalidixic acid (71%), ampicillin (69%), and ampicillin/sulbactam (46%), and demonstrated that the novel L2/4 was a multidrug-resistant lineage. This study provides novel insight into the genomic epidemiology and antimicrobial susceptibility profile of ETEC infections in indigenous adults for the first time, which further improves our understanding on ETEC epidemiology and has implications for the development of vaccine and future surveillance and prevention of ETEC infections.