Update in traveler's diarrhea

TD has not proved as preventable as hoped, despite knowing that it is transmitted mainly through food. Travelers have little ability to select restaurants based on the kitchen hygiene. The rates of TD in travelers to developing countries have not changed in the past 50 years, either because the dietary precautions they are taught are not effective or they cannot be adhered to in the course of a pleasurable vacation. Nonantibiotic prophylaxis with bismuth subsalicylate has the potential to prevent 40% to 60% of TD episodes in short-term travelers, and is probably underused. Antibiotic prophylaxis can prevent up to 90% of infections, but is not routinely recommended. Empiric treatment of TD has been the best approach to dealing with this problem, but its usefulness is being undermined by growing antibiotic resistance in many parts of the world. Fluoroquinolones are still the most useful agents where Campylobacter is not a predominant pathogen. Rifaximin may prove to be a useful addition to the options for treatment and prophylaxis. If used for treatment, it may require a backup antibiotic in areas where Campylobacter and Shigella are prominent pathogens.     

旅行者腹泻患者寄生虫感染研究进展

随着全球旅游业的飞速发展,旅行日渐成为日常生活的重要组成部分,旅行者健康问题也越来越引起重视.旅行者腹泻为跨国或跨地区旅行者中最常见的疾病之一,造成了极大的疾病和经济负担.目前,我国仍缺乏寄生虫病相关病原体与旅行者腹泻关系的系统性研究.本文主要就旅行者腹泻患者肠道原虫及蠕虫等寄生虫感染情况作一综述,以期为制定与旅行者腹...     

Prevention of traveler's diarrhea.

Preventing traveler's diarrhea is usually a matter of common sense, good luck, and the host's ability to defend against enteric pathogens, particularly enterotoxigenic Escherichia coli. Untreated tap water, ice cubes, unpasteurized milk products, salads, food from street vendors, and dining in unhygienic-appearing restaurants should be avoided. Well-cooked food that is served hot and carbonated, commercially bottled beverages are usually safe. Food and water precautions, however, are no guarantee of success in preventing traveler's diarrhea. Bismuth subsalicylate used prophylactically is somewhat inconvenient and is only moderately effective. Although antibiotic prophylaxis is very effective for traveler's diarrhea, particularly the quinolones, it should be reserved for high-risk travelers.     

Efficacy of bicozamycin in preventing traveler's diarrhea

Bicozamycin was compared with a placebo in a prospective, randomized, double-blind study of the prevention of acute diarrhea among 30 American travelers newly arrived in Guadalajara, Mexico. None of the 11 subjects given bicozamycin orally for 3 wk at a dosage of 500 mg four times a day developed diarrhea as compared with an incidence of 53% diarrhea (10 of 19 subjects) in the placebo group (p = 0.003). Bicozamycin was well tolerated. Studies of changes in predominant aerobic fecal flora among the 11 subjects treated with bicozamycin showed the appearance of only one highly resistant Citrobacter freundii at the end of 1 wk of therapy and only a total of six resistant isolates at the end of 3 wk. All resistant isolates failed to transfer this resistance to a recipient Escherichia coli. Bicozamycin seems to be well suited and safe as a prophylactic agent against traveler's diarrhea.     

Empirical antimicrobial therapy for traveler's diarrhea.

Over 7 million cases of traveler's diarrhea, defined as the passage of > or = 3 unformed stools in a 24-h period, occur each year among visitors to developing countries. Bacterial enteric pathogens are the most common etiologic agents isolated. Preliminary clinical results for patients with diarrhea predominantly caused by Campylobacter species have shown that azithromycin may be an effective alternative to fluoroquinolones for the treatment of traveler's diarrhea.     

Enteroaggregative escherichia coli virulence factors in traveler's diarrhea strains

Enteroaggregative Escherichia coli (EAEC) is associated with diarrhea in Spanish travelers to developing countries. In this study, the polymerase chain reaction was used to test EAEC isolates for genes encoding putative virulence factors, including EAEC adhesins, the plasmid-encoded toxin (Pet), a heat-stable enterotoxin (EAST), and Shigella enterotoxins 1 and 2 (ShET1 and ShET2). Findings included a low prevalence of genes for Pet (4.3%), ShET2 (4.3%), and the adherence factor AAF/II (8.7%). The overlapping genes encoding the ShET1 and the Pic mucinase were present in most EAEC strains tested (56.5%); however, some strains that carried this locus did not produce both proteins, as determined by Western immunoblot. Surprisingly, ShET1 and ShET2 genes were also found in other E. coli pathotypes, as was the EAST toxin locus. These findings underscore the heterogeneity of EAEC strains and suggest that the ShET1 may be an important virulence factor in traveler's diarrhea.     

Epidemiology, etiology and pathophysiology of traveler's diarrhea

Traveler's diarrhea (TD) is the most frequent health problem in travelers to developing countries. Several personal and environmental risk factors are at the basis of TD acquisition and are discussed in this paper. TD is caused by a wide range of infectious organisms, ETEC and EAEC bacteria strains being the main enteropathogens incriminated in TD. Other causative bacteria are: Shigella spp., Campylobacter spp., Vibrio spp., Aeromonas spp., Salmonella spp., and Plesiomonas spp. Parasite species are also included: Cyclospora cayetanensis, Giardia lamblia, Cryptosporidium, Entamoeba histolytica, as well as viruses: rotavirus, adenovirus, Norwalk virus. Due to the great diversity of pathogens incriminated, several pathophysiological mechanisms have been described and some of them are still poorly understood. The clinical symptoms present are also quite variable, although inflammatory and non-inflammatory diarrhea have been established as a classical and basic classification of diarrhea.     

Treatment of traveler's diarrhea with ciprofloxacin and loperamide.

To determine the efficacy of loperamide given with long- and short-course quinolone therapy for treating traveler's diarrhea, 142 US military personnel were randomized to receive a single 750-mg dose of ciprofloxacin with placebo, 750 mg of ciprofloxacin with loperamide, or a 3-day course of 500 mg of ciprofloxacin twice daily with loperamide. Culture of pretreatment stool specimens revealed campylobacters (41%), salmonellae (18%), enterotoxigenic Escherichia coli (ETEC, 6%), and shigellae (4%). Of the participants, 87% completely recovered within 72 h of entry. Total duration of illness did not differ significantly among the three treatment groups, but patients in the 3-day ciprofloxacin plus loperamide group reported a lower cumulative number of liquid bowel movements at 48 and 72 h after enrollment compared with patients in the single-dose ciprofloxacin plus placebo group (1.8 vs. 3.6, P = .01; 2.0 vs. 3.9, P = .01). While not delivering a remarkable therapeutic advantage, loperamide appears to be safe for treatment of non-ETEC causes of traveler's diarrhea. Two of 54 patients with Campylobacter enteritis had a clinical relapse after treatment that was associated with development of ciprofloxacin resistance.     

Meta-analysis of probiotics for the prevention of traveler's diarrhea

BACKGROUND: Traveler's diarrhea (TD) is a common health complaint among travelers. Rates of TD can range from 5% to 50%, depending on the destination. The use of probiotics for this disease remains controversial. The objective of this study was to compare the efficacy of probiotics for the prevention of TD based on published randomized, controlled clinical trials. METHODS: PubMed, Google Scholar, metaRegister, NIH registry of clinical trials and Cochrane Central Register of Controlled Trials were searched from 1977 to 2005, unrestricted by language. Secondary searches of reference lists, authors, reviews, commentaries, associated diseases, books and meeting abstracts. Inclusion criteria included: randomization, controlled, blinded, efficacy trials, in humans, peer-reviewed journals. Exclusion criteria were: pre-clinical, safety, phase 1 studies in volunteers, reviews, duplicate reports, trials of unspecified probiotics, trials of prebiotics, and inconsistent outcome measures. RESULTS: Twelve of 940 screened studies met the inclusion and exclusion criteria. The pooled relative risk indicates that probiotics significantly prevent TD (RR=0.85, 95% CI 0.79,0.91, p<0.001). CONCLUSION: Several probiotics (Saccharomyces boulardii and a mixture of Lactobacillus acidophilus and Bifidobacterium bifidum) had significant efficacy. No serious adverse reactions were reported in the 12 trials. Probiotics may offer a safe and effective method to prevent TD.     

Prevention and treatment of traveler's diarrhea. Focus on antimicrobial agents

Diarrhea, mostly due to bacterial infection of the gut, is the most frequent health complaint in the international traveler, affecting 20-70% of the traveling population depending on the destination and other factors. It is usually benign and self-limiting in nature, but symptoms may occasionally be distressing causing modifications of normal activities and sometimes confinement to bed or hospitalization. Prevention of traveler's diarrhea should ideally be based on dietary restrictions, but experience shows that this target is extremely difficult to achieve. Antibiotic chemoprophylaxis should be restricted to selected groups of travelers at risk of severe complications of diarrhea or when diarrhea-driven alterations of planned activities are highly undesirable (critical trips). The effectiveness of alternative prophylactic approaches, such as vaccination or the use of probiotics, still awaits confirmation. Treatment of mild diarrheal cases without intestinal symptoms may be limited to rehydration with or without antimotility agents. When antibiotic therapy is considered, non-absorbable antibiotics, such as rifaximin, may be considered a valid alternative to systemic antibiotics to treat uncomplicated cases, leaving fluoroquinolones and/or azithromycin for use in more severe cases or when invasive pathogens are suspected. Indeed, therapeutic use of doxycycline and trimethoprim-sulfamethoxazole (TMP-SMX) is limited by widespread resistance of many enteropathogens. The addition of loperamide or other antimotility agents usually provides symptom relief and further shortens the duration of illness and may be therefore safely adopted in the healthy adult unless dysentery is present.