Traveler's diarrhea [keywords]
- Use of rifaximin in gastrointestinal and liver diseases. [Journal Article, Review]
- World J Gastroenterol 2016 Aug 7; 22(29):6638-51.
Rifaximin is a broad spectrum oral antibiotic with antimicrobial activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria. It is poorly absorbed and thus has a highly favorable safety profile. Rifaximin has been shown to be effective in the treatment of traveler's diarrhea, functional bloating and irritable bowel syndrome, small bowel bacterial overgrowth and in the prevention of recurrent overt hepatic encephalopathy. In addition, there is emerging evidence for a possible beneficial effect of rifaximin in the treatment of uncomplicated diverticular disease and in the prevention of recurrent diverticulitis. The use of rifaximin is associated with a low incidence of development, or persistence of spontaneous bacterial mutants. Moreover, the development of important drug resistance among extra-intestinal flora during rifaximin therapy is unlikely because of minimal systemic absorption and limited cross-resistance of rifaximin with other antimicrobials. This review addresses the current and emerging role of rifaximin in the treatment of gastrointestinal and liver disorders.
- Effects of lng Mutations on LngA Expression, Processing, and CS21 Assembly in Enterotoxigenic Escherichia coli E9034A. [Journal Article]
- Front Microbiol 2016.:1201.
Enterotoxigenic Escherichia coli (ETEC) is a major cause of morbidity in children under 5 years of age in low- and middle-income countries and a leading cause of traveler's diarrhea worldwide. The ability of ETEC to colonize the intestinal epithelium is mediated by fimbrial adhesins, such as CS21 (Longus). This adhesin is a type IVb pilus involved in adherence to intestinal cells in vitro and bacterial self-aggregation. Fourteen open reading frames have been proposed to be involved in CS21 assembly, hitherto only the lngA and lngB genes, coding for the major (LngA) and minor (LngB) structural subunit, have been characterized. In this study, we investigated the role of the LngA, LngB, LngC, LngD, LngH, and LngP proteins in the assembly of CS21 in ETEC strain E9034A. The deletion of the lngA, lngB, lngC, lngD, lngH, or lngP genes, abolished CS21 assembly in ETEC strain E9034A and the adherence to HT-29 cells was reduced 90%, compared to wild-type strain. Subcellular localization prediction of CS21 proteins was similar to other well-known type IV pili homologs. We showed that LngP is the prepilin peptidase of LngA, and that ETEC strain E9034A has another peptidase capable of processing LngA, although with less efficiency. Additionally, we present immuno-electron microscopy images to show that the LngB protein could be localized at the tip of CS21. In conclusion, our results demonstrate that the LngA, LngB, LngC, LngD, LngH, and LngP proteins are essential for CS21 assembly, as well as for bacterial aggregation and adherence to HT-29 cells.
- Characterization of Polymorphic Forms of Rifaximin. [Journal Article]
- J AOAC Int 2016 Jul; 99(4):964-71.
Rifaximin is a gut-selective oral antimicrobial that has no systemic adverse effects compared with placebo. It is used for the treatment of hepatic encephalopathy, traveler's diarrhea, irritable bowel syndrome, Clostridium difficile infection, ulcerative colitis, and acute diarrhea. The crystalline form present in rifaximin, α, has minimal systemic absorption compared to the amorphous form. The objective of this study was to obtain polymorphic forms of rifaximin using recrystallization processes. The forms were characterized and studied by thermal analysis, X-ray powder diffraction, scanning electron microscopy, and solubility testing. Six polymorphic forms of rifaximin, designated I-VI, were obtained by the crystallization process by evaporation of the solvent. Some polymorphic forms obtained in this work may not have the same excellent tolerability as the reference medicine; therefore, studies such as these are extremely important and point to the need for greater requirements by the regulatory agencies overseeing polymorph analysis of the raw materials used in the manufacture of medicines marketed globally. These analyses are not required in the majority of official compendia. Partnerships among industries, research centers, and universities would be a viable way to consolidate research in this area and contribute to improving the quality of solid drugs.
- The Traveling Microbiome. [Journal Article, Review]
- Curr Infect Dis Rep 2016 Sep; 18(9):29.
Given the recent interest in the human gut microbiome in health and disease, we have undertaken a review of the role of the gut microbiome as it relates to travel. Considering the microbiome as the interface with the external world of the traveler, not only from the perspective of protection from enteric infection by colonization resistance but also the possibility that a traveler's unique microbiome may place him or her at lesser or greater risk for enteric infection. We review available data on travel, travelers' diarrhea, and the use of antibiotics as it relates to changes in the microbiome and the acquisition of multi-drug-resistant bacteria and explore the interplay of these factors in the development of dysbiosis and the post-infectious sequelae of TD, specifically PI-IBS. In addition, we explore whether dietary changes in travel affect the gut microbiome in a way which modulates gastrointestinal function and susceptibility to infection and discuss whether pre- or probiotics have any meaningful role in prevention or treatment of TD. Finally, a discussion of important research gaps and opportunities in this area is identified.
- Synthesis of the Heptasaccharide Repeating Unit of the Cell Wall O-Polysaccharide of Enterotoxigenic Escherichia coli O139. [Journal Article]
- ChemistryOpen 2016 Feb; 5(1):43-6.
Enterotoxigenic Escherichia coli (ETEC) like the O139 strain are mostly responsible for traveler's diarrhea and causes diseases in pigs, cattle, and poultry. A convenient synthetic strategy was developed for the synthesis of the heptasaccharide repeating unit of the cell wall lipopolysaccharide of the E. coli O139 strain. The p-methoxybenzyl (PMB) group was used as a temporary protecting group which was removed in situ under the glycosylation conditions by changing the reaction temperature during the synthesis of the target compound. All glycosylation steps gave high yields with good stereoselectivity. A (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-mediated selective oxidation of the primary hydroxyl group was carried out using a biphasic reaction condition at the late stage of the synthesis. Such synthetic oligosaccharides could later be effectively conjugated with proteins to prepare glycoconjugate derivatives as vaccine candidates.
- Multi drug resistance and Extended Spectrum Beta Lactamases in clinical isolates of Shigella: A study from New Delhi, India. [Journal Article]
- Travel Med Infect Dis 2016 Jul-Aug; 14(4):407-13.
Shigella is an important cause of gastroenteritis in local Indian population, as well as of traveler's diarrhea in the international visitors to India. These patients often require appropriate antimicrobial therapy; however, rapid development of antimicrobial resistance poses a major hurdle in achieving this goal.A prospective study was conducted during 2009-12 in New Delhi, India, including 6339 stool samples from gastroenteritis patients. 121 Shigella strains were identified on the basis of colony morphology, biochemical reactions, serotyping and ipaH gene based PCR. Antimicrobial susceptibility testing by disc diffusion, MIC determination by Vitek(®) 2 and phenotypic tests for ESBL/AmpC production were done.Nineteen percent strains (23/121) were found to be resistant to third generation cephalosporins and all were phenotypically confirmed to be ESBL producers; one strain was positive for AmpC. ESBL producing strains were also found to be significantly more resistant (p < 0.05) to several other antimicrobials agents in comparison to ESBL non-producers, [ampicillin (100% vs. 62.2%), ampicillin/sulbactam (100% vs. 30.6%), cotrimoxazole (100% vs. 77.6%), ciprofloxacin (87.0% vs. 49.0%), ofloxacin (87.0% vs. 52.0%) and gentamicin (30.4% vs. 7.1%)]. Multidrug resistance was seen in 76% strains.Inappropriate use of antimicrobial agents puts high selection pressure on the higher-end antibiotics. Multi-drug resistance and high rates of ESBL production by Shigella is a matter of concern for the local population as well as international travelers. Therefore, better national level antimicrobial management programs are the priority needs.
- Small Intestinal Infections. [Journal Article, Review]
- Curr Gastroenterol Rep 2016 Jun; 18(6):31.
Small intestinal infections are extremely common worldwide. They may be bacterial, viral, or parasitic in etiology. Most are foodborne or waterborne, with specific etiologies differing by region and with diverse pathophysiologies. Very young, very old, and immune-deficient individuals are the most vulnerable to morbidity or mortality from small intestinal infections. There have been significant advances in diagnostic sophistication with the development and early application of molecular diagnostic assays, though these tests have not become mainstream. The lack of rapid diagnoses combined with the self-limited nature of small intestinal infections has hampered the development of specific and effective treatments other than oral rehydration. Antibiotics are not indicated in the absence of an etiologic diagnosis, and not at all in the case of some infections.
- [Characteristics associated with pre travel medical consultation in tourists visiting Cuzco, Peru]. [English Abstract, Journal Article]
- Rev Chilena Infectol 2016 Feb; 33(1):38-42.
International tourism is increasing. Preventive Medicine remains important, especially the Pre-Travel Consultation (PTC).To determinate, the characteristics of tourists associated with PTC in tourists at Cuzco, Peru.A cross-sectional, analytical study, a secondary analysis of data from a database generated by survey of foreign tourists who visited Cuzco, in the waiting room of the airport was performed. The main variable was to have had a PTC at the tourist's country of residence, the area of residence was categorized according to health/risk of acquiring infectious diseases as traveler's diarrhea during their stay. These and other variables were analyzed and statistical association with generalized linear models were done.Of the 1827 tourists, 875 (48%) were men, with a median age of 33 years (range 18-88 years); 42% had a PTC. In the multivariate analysis, it was found that a PTC lower frequency was associated with male gender (aPR: 0.84; 95% CI: 0.75-0.94), and a higher frequency was associated with have born (aPR: 1.77; 95% CI: 1.39-2.27) and reside in an area of low risk of acquiring infectious diseases (aPR: 1.95; 95% CI: 1.26-3.00), adjusted for the history of a disease.Sex, region of birth and residence of tourists (as risk of acquiring infectious diseases) are associated with having a PTC. These findings may serve the health and government attending tourists who come to our country.
- Traveler's Diarrhea. [Journal Article, Review]
- Med Clin North Am 2016 Mar; 100(2):317-30.
Traveler's diarrhea (TD) is the most common travel-related illness, and it can have a significant impact on the traveler. Pretravel consultation provides an excellent opportunity for the clinician to counsel the traveler and discuss strategies such as food and water hygiene, vaccinations, and medications for prophylaxis or self-treatment that may decrease the incidence and impact of TD. Postinfectious sequelae, such as postinfectious irritable bowel syndrome, reactive arthritis, and Guillain-Barre syndrome, may develop weeks or months after return.
- Travel Medical Kit. [Journal Article, Review]
- Med Clin North Am 2016 Mar; 100(2):261-77.
"The traveler's medical kit is an essential tool for both the novice and expert traveler. It is designed to treat travel-related illness and injury and to ensure preexisting medical conditions are managed appropriately. Travelers are at increased risk for common gastrointestinal issues during travel. Respiratory illnesses make up approximately 8% of the ailments present in returned international travelers. Approximately 12% of travelers experience a travel-related skin condition. First aid treatment for minor injuries is essential to all travel medical kits. The complexity ranges from a small, simple case for the urban traveler to a larger, extensive case for wilderness travel."