New insights and directions in travelers' diarrhea

Colonization with extended-spectrum beta-lactamase-producing Escherichia coli and traveler's diarrhea attack rates among travelers to India: a systematic review and meta-analysis

Background

India is an attractive destination for travelers. Unfortunately, numerous reports exist on traveler’s diarrhea (TD) and fecal colonization with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) among international travelers visiting India. Here, we systematically reviewed studies published on the acquisition of ESBL-EC and TD attack rates among international visitors to India.

Methods

Design: Systematic review and meta-analysis.

A systematic search was performed using Google Scholar, PubMed, EMBASE, Web of Science, and gray literature from 2000 to December 2021, for studies containing data for ESBL-EC acquisition or TD experience related to a trip to India. Random effects models were used to compute the prevalence of ESBL-EC acquisition and TD attack.

Results

The literature search yielded a total of 5023 records. Of these, 31 met our inclusion criteria for systematic review and only 17 could be meta-analyzed (9 for TD, and 8 for ESBL-EC). The overall pooled attack rate of TD was 39% (95% confidence interval, CI: 25–53%). In studies where travelers' memory was used to diagnose TD, the pooled attack rate of TD was slightly higher (42%, 95% CI: 21–64%) compared to those where TD was objectively documented (33%, 95% CI: 17–49%). There were significant risks to be colonized with ESBL-EC among the travelers who experienced TD. The pooled rate of ESBL-EC colonization was 72% (CI: 67–78%). Most ESBL-EC produced CTX-M-15 enzyme. Furthermore, most of the travelers who acquired ESBL-EC were from highly industrialized countries recruited from travel clinics: Canada (n = 80), Germany (n = 69), Netherlands (n = 20), Sweden (n = 18), Japan (n = 10), Finland (n = 8), USA (n = 7), Spain (n = 5), and Denmark (n = 3).

Conclusions

TD pooled attack rate and ESBL-EC acquisition among international travelers visiting India were high in this study. However, we cannot make generalizations based upon this TD pooled attack rate for the current situation, due to a lack of current data. Our study highlights that travelers should be advised on TD to ensure that they do not disregard the risk of contracting TD and be better prepared as a result. It also illustrates the importance of international travel in acquiring antibiotic-resistant Escherichia coli.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40794-022-00179-1.

ACG Clinical Guideline: Diagnosis, Treatment, and Prevention of Acute Diarrheal Infections in Adults

Acute diarrheal infections are a common health problem globally and among both individuals in the United States and traveling to developing world countries. Multiple modalities including antibiotic and non-antibiotic therapies have been used to address these common infections. Information on treatment, prevention, diagnostics, and the consequences of acute diarrhea infection has emerged and helps to inform clinical management. In this ACG Clinical Guideline, the authors present an evidence-based approach to diagnosis, prevention, and treatment of acute diarrhea infection in both US-based and travel settings.

Post-infectious sequelae of travelers' diarrhea

BACKGROUND

Travelers' diarrhea (TD) has generally been considered a self-limited disorder which resolves more quickly with expeditious and appropriate antibiotic therapy given bacteria are the most frequently identified cause. However, epidemiological, clinical, and basic science evidence identifying a number of chronic health conditions related to these infections has recently emerged which challenges this current paradigm. These include serious and potentially disabling enteric and extra-intestinal long-term complications. Among these are rheumatologic, neurologic, gastrointestinal, renal, and endocrine disorders. This review aims to examine and summarize the current literature pertaining to three of these post-infectious disorders: reactive arthritis, Guillain-Barré syndrome, and post-infectious irritable bowel syndrome and the relationship of these conditions to diarrhea associated with travel as well as to diarrhea associated with gastroenteritis which may not be specifically travel related but relevant by shared microbial pathogens. It is hoped this review will allow clinicians who see travelers to be aware of these post-infectious sequelae thus adding to our body of knowledge in travel medicine.

METHODS

Data for this article were identified by searches of PubMed and MEDLINE, and references from relevant articles using search terms "travelers' diarrhea" "reactive arthritis" "Guillain-Barré syndrome" "Post-Infectious Irritable Bowel Syndrome." Abstracts were included when related to previously published work.

RESULTS AND CONCLUSIONS

A review of the published literature reveals that potential consequences of travelers' diarrhea may extend beyond the acute illness and these post-infectious complications may be more common than currently recognized. In addition since TD is such a common occurrence it would be helpful to be able to identify those who might be at greater risk of post-infectious sequelae in order to target more aggressive prophylactic or therapeutic approaches to such individuals. It is hoped this review will allow clinicians who see travelers to be aware of these post-infectious sequelae thus adding to our body of knowledge in travel medicine.

Diarrhoeal episodes in travellers suffering from IBD

BACKGROUND AND AIMS

There is limited data on the risk of developing diarrhoea in travelling patients with inflammatory bowel disease (IBD). We analysed the rate of developing diarrhoea among travellers suffering from IBD and their healthy controls.

METHODS

We performed a retrospective case-controlled study among 78 patients with IBD and their healthy travelling companion controls, thus matching both groups to the same environmental conditions. Data was retrieved through a structured questionnaire, interview and clinical case notes review.

RESULTS

Sixteen (20.5%) patients with IBD developed diarrhoea while abroad (p -0.0001) Statistical analysis using a χ² test for independence (with Yates Continuity Correction). Prior to travelling, they were in clinical remission. Only one healthy control (1.3%) developed diarrhoea while abroad. In 11 patients (14.1%), the duration of diarrhoea was 3 days or less, and resolved on its own without antibiotics, any increase in their IBD medications and without a medical consultation. The other five patients had a flare-up of their disease and needed medications to put them back into remission. There was no statistically significant difference between patients having immunomodulator medications versus those having aminosalicylates only in developing diarrhoea when abroad.

CONCLUSIONS

Patients with IBD have a higher rate of developing diarrhoea compared with controls when travelling. Thus, such patients must always seek a pretravel medical consultation.

Effectiveness of rifaximin and fluoroquinolones in preventing travelers' diarrhea (TD): a systematic review and meta-analysis

BACKGROUND

Recent developments related to a safe and effective nonabsorbable antibiotic, rifaximin, and identification of postinfectious irritable bowel syndrome as a frequent sequela call for a need to reconsider the value of primary prevention of traveler's diarrhea (TD) with antibiotics.

METHODS

Randomized, placebo-controlled, double-blind studies evaluating the effectiveness and safety of rifaximin or a fluoroquinolone chemoprophylaxis against TD were pooled using a random effects model and assessed for heterogeneity.

RESULTS

The nine studies (four rifaximin and five fluoroquinolone) included resulted in pooled relative risk estimates of 0.33 (95% CI = 0.24-0.45, I2 = 3.1%) and 0.12 (95% CI = 0.07-0.20, I2 =0.0%), respectively. Similar rates of treatment emergent adverse events were found between antibiotic and placebo groups.

CONCLUSIONS

This meta-analysis supports the effectiveness of antibiotics in preventing TD. However, further studies that include prevention of secondary chronic health outcomes among travelers to different geographic regions, and a formal risk-benefit analysis for antibiotic chemoprophylaxis, are needed.

Serum antibodies protect against intraperitoneal challenge with enterotoxigenic Escherichia coli

To assess whether anticolonization factor antigen I (CFA/I) fimbriae antibodies (Abs) from enterotoxigenic Escherichia coli (ETEC) can protect against various routes of challenge, BALB/c mice were immunized with a live attenuated Salmonella vaccine vector expressing CFA/I fimbriae. Vaccinated mice elicited elevated systemic IgG and mucosal IgA Abs, unlike mice immunized with the empty Salmonella vector. Mice were challenged with wild-type ETEC by the oral, intranasal (i.n.), and intraperitoneal (i.p.) routes. Naïve mice did not succumb to oral challenge, but did to i.n. challenge, as did immunized mice; however, vaccinated mice were protected against i.p. ETEC challenge. Two intramuscular (i.m.) immunizations with CFA/I fimbriae without adjuvant conferred 100% protection against i.p. ETEC challenge, while a single 30 μg dose conferred 88% protection. Bactericidal assays showed that ETEC is highly sensitive to anti-CFA/I sera. These results suggest that parenteral immunization with purified CFA/I fimbriae can induce protective Abs and may represent an alternative method to elicit protective Abs for passive immunity to ETEC.

In vitro antimicrobial susceptibility of bacterial enteropathogens isolated from international travelers to Mexico, Guatemala, and India from 2006 to 2008

The incidence rates of travelers' diarrhea (TD) have remained high for the last 50 years. More recently, there have been increasing recommendations for self-initiated therapy and use of prophylactic drugs for TD. We last examined the in vitro susceptibilities of commonly used antibiotics against TD pathogens in 1997. We now examine 456 enteropathogens isolated from adult travelers to Mexico, India, and Guatemala with diarrhea acquired between 2006 and 2008 to determine changes in susceptibility against 10 different antimicrobials by the agar dilution method. Traditional antibiotics, such as ampicillin, trimethoprim-sulfamethoxazole, and doxycycline, continue to show high levels of resistance. Current first-line antibiotic agents, including fluoroquinolones and azithromycin, showed significantly higher MICs than in our earlier study, and MIC(90) levels were above the Clinical and Laboratory Standards Institute cutoffs for resistance. There were significant geographical differences in resistance patterns when Central America was compared with India. Entertoxigenic Escherichia coli (ETEC) isolates showed increased resistance to ciprofloxacin (P = 0.023) and levofloxacin (P = 0.0078) in India compared with Central America. Enteroaggregative E. coli (EAEC) isolates from Central America showed increased resistance to nearly all of the antibiotics tested. Compared to MICs of isolates 10 years prior, there were 4- to 10-fold increases in MIC(90) values for ceftriaxone, ciprofloxacin, levofloxacin, and azithromycin for both ETEC and EAEC. There were no significant changes in rifaximin MICs. Rising MICs over time imply the need for continuous surveillance of susceptibility patterns worldwide and geographically specific recommendations in TD therapy.

Prevention of travelers' diarrhea with rifaximin in US travelers to Mexico

BACKGROUND

Because bacterial pathogens are the primary cause of travelers' diarrhea (TD), antibiotic prophylaxis is effective in TD prevention. This study assessed the efficacy and safety of the nonsystemic antibiotic rifaximin in preventing TD in US travelers to Mexico.

METHODS

Healthy adult students traveling to Mexico received rifaximin 600 mg/d or placebo for 14 days and were followed for 7 days post-treatment. Stool pattern and gastrointestinal symptoms were recorded in daily diary entries. The primary end point was prevention of TD during 14 days of treatment measured by time to first unformed stool.

RESULTS

A total of 210 individuals received rifaximin (n = 106) or placebo (n = 104) and were included in the safety population. Median age was 21 years (range, 18-75 y), and the majority of participants were female (65%). Efficacy analyses were conducted in a modified intent-to-treat population of 201 patients who received rifaximin (n = 99) or placebo (n = 102). Rifaximin prophylaxis reduced risk of developing TD versus placebo (p < 0.0001). A smaller percentage of individuals who received rifaximin versus placebo developed all-cause TD (20% vs 48%, respectively; p < 0.0001) or TD requiring antibiotic therapy (14% vs 32%, respectively; p = 0.003). More individuals in the rifaximin group (76%) completed treatment without developing TD versus those in the placebo group (51%; p = 0.0004). Rifaximin provided a 58% protection rate against TD and was associated with fewer adverse events than placebo.

CONCLUSIONS

Prophylactic treatment with rifaximin 600 mg/d for 14 days safely and effectively reduced the risk of developing TD in US travelers to Mexico. Rifaximin chemoprevention should be considered for TD in appropriate individuals traveling to high-risk regions.

The role of rifaximin in the treatment and chemoprophylaxis of travelers' diarrhea

Travelers’ diarrhea is a common illness among international travelers from developed to developing countries. Travelers’ diarrhea is caused by ingestion of contaminated food and water. Bacteria are the primary cause of travelers’ diarrhea. In most surveys, the most common diarrheal pathogen identified is enterotoxigenic Escherichia coli. There are several antimicrobial agents available for the treatment of travelers’ diarrhea including rifaximin which is approved in the United States for the treatment of travelers’ diarrhea due to noninvasive E. coli strains. In this review, we will review the most recent advances of rifaximin for the treatment and prevention of travelers’ diarrhea, with regard to its pharmacokinetics, in vitro susceptibility profile, and efficacy and safety data from clinical trials.

Travelers' preferences for the treatment and prevention of acute diarrhea

BACKGROUND

A survey was designed to assess travelers' willingness to take antibiotic chemoprophylaxis against travelers' diarrhea (TD) or to intervene with antibiotic or symptomatic treatments.

METHODS

A brief written questionnaire was administered to clients in North American (United States and Canadian) and European (UK and German) travel clinic waiting rooms to assess length, purpose, and destination of their upcoming trips; their perceived risk of developing TD at their destination; and their preferences for hypothetical treatment or chemoprophylaxis options, which included descriptions, but no mention of brand names, of a systemically absorbed antibiotic based on a fluoroquinolone, a nonabsorbed antibiotic based on rifaximin, and an over-the-counter antidiarrheal similar to loperamide.

RESULTS

The 209 UK and German travelers planned significantly longer travel than the 277 US and Canadian travelers (25 vs 15 d, p < 0.001) and correctly recognized high risk of TD more often than the North Americans (81% vs 61%, p < 0.001). More of the North Americans preferred any therapy options compared with the Europeans; only 14% of the North Americans preferred no treatment compared with 29% of the Europeans (p < 0.001). More of the North Americans and the Europeans preferred the nonabsorbed antibiotic than the systemically absorbed antibiotic, regardless of if combined with the antidiarrheal agent. Significantly more of the Europeans preferred not to take antibiotic chemoprophylaxis than North Americans (66% vs 37%, p < 0.001). Among the North Americans, significantly more travelers preferred chemoprophylaxis with the nonabsorbed than the systemic antibiotic (45% vs 33%, p= 0.003).

CONCLUSIONS

Among the relatively small groups of travelers studied, the UK and German travelers were more cognizant of TD risk than US and Canadian travelers. The Europeans were less inclined to take chemoprophylaxis or treatment. Both groups preferred treatment or prophylaxis with the nonabsorbed antibiotic over the systemically absorbed antibiotic or the antidiarrheal agent.

Diagnosis and treatment of acute or persistent diarrhea

Studies of microbial pathogens and the toxins they produce are important for determining the mechanisms by which they cause disease and spread throughout a population. Some bacteria produce secretory enterotoxins (such as cholera toxin or the heat-labile or stable enterotoxins produced by Escherichia coli) that invade cells directly. Others invade cells or produce cytotoxins (such as those produced by Shigella, enteroinvasive E coli, or Clostridium difficile) that damage cells or trigger host responses that cause small or large bowel diseases (such as enteroaggregative or enteropathogenic E coli or Salmonella). Viruses (such as noroviruses and rotaviruses) and protozoa (such as Cryptosporidium, Giardia, or Entamoeba histolytica) disrupt cell functions and cause short- or long-term disease. Much epidemiologic data about these pathogens have been collected from community- and hospital-acquired settings, as well as from patients with traveler's or persistent diarrhea. These studies have led to practical approaches for prevention, diagnosis, and treatment.

High dosage rifaximin for the treatment of small intestinal bacterial overgrowth

BACKGROUND

Rifaximin is a broad spectrum non-absorbable antibiotic used for treatment of small intestinal bacterial overgrowth. Doses of 1200 mg/day showed a decontamination rate of 60% with low side-effects incidence.

AIMS

To assess efficacy, safety and tolerability of rifaximin 1600 mg with respect to 1200 mg/day for small intestinal bacterial overgrowth treatment.

METHODS

Eighty consecutive small intestinal bacterial overgrowth patients were enrolled. Diagnosis of small intestinal bacterial overgrowth based the clinical history and positivity to H(2)/CH(4) glucose breath test. Patients were randomized in two 7-day treatment groups: rifaximin 1600 mg (group 1); rifaximin 1200 mg (group 2). Glucose breath test was reassessed 1 month after. Compliance and side-effect incidence were also evaluated.

RESULTS

One drop-out was observed in group 1 and two in group 2. Glucose breath test normalization rate was significantly higher in group 1 with respect to group 2 both in intention-to-treat (80% vs. 58%; P < 0.05) and per protocol analysis (82% vs. 61%; P < 0.05). No significant differences in patient compliance and incidence of side effects were found between groups.

CONCLUSIONS

Rifaximin 1600 mg/day showed a significantly higher efficacy for small intestinal bacterial overgrowth treatment with respect to 1200 mg with similar compliance and side-effect profile.

Turista: diarrhées du voyageur

Travelers' diarrhea is an important health concern for travelers, with an attack rate of approximately 40%. Except in the elderly or young children, who may have severe cases, travelers' diarrhea is usually mild but can lead to significant discomfort and to chronic forms. Bacteria, especially enterotoxinogenic E. coli, are its principal causes. Unsafe solid food is, even more than water, its main vector. Quinolones and azithromycin are very effective but rehydration remains the cornerstone of treatment. Quinolones can be used for preventive treatment but only for travelers at high risk. Other means of prevention include food hygiene, although its effectiveness is limited. More useful than forbidding foods is counseling travelers to wash their hands and eat safe food (cooked, hot). Preventive nonabsorbed antiinfective agents and vaccination against enterotoxinogenic E. coli should be available relatively soon and will decrease the incidence of travelers' diarrhea.