Traveler's diarrhea [keywords]
- 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 May 24.
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."
- Real-Time TaqMan PCR Assay for the Detection of Heat-Labile and Heat-Stable Enterotoxin Genes in a Geographically Diverse Collection of Enterotoxigenic Escherichia coli Strains and Stool Specimens. [Journal Article]
- Foodborne Pathog Dis 2016 Apr; 13(4):212-20.
Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrhea in children under the age of 5 years in developing countries and are the leading bacterial agent of traveler's diarrhea in persons traveling to these countries. ETEC strains secrete heat-labile (LT) and/or heat-stable (ST) enterotoxins that induce diarrhea by causing water and electrolyte imbalance. We describe the validation of a real-time TaqMan PCR (RT-PCR) assay to detect LT, ST1a, and ST1b enterotoxin genes in E. coli strains and in stool specimens. We validated LT/ST1b duplex and ST1a single-plex RT-PCR assay using a conventional PCR assay as a gold standard with 188 ETEC strains and 42 non-ETEC strains. We validated LT/ST1b duplex and ST1a single-plex RT-PCR assay in stool specimens (n = 106) using traditional culture as the gold standard. RT- PCR assay sensitivities for LT, ST1a, and ST1b detection in strains were 100%, 100%, and 98%; specificities were 95%, 98%, and 99%, and Pearson correlation coefficient r was 0.9954 between RT-PCR assay and the gold standard. In stool specimens, RT-PCR assay sensitivities for LT, ST1a, and ST1b detection were 97%, 100%, and 97%; and specificities were 99%, 94%, and 97%. Pearson correlation coefficient r was 0.9975 between RT-PCR results in stool specimens and the gold standard. Limits of detection of LT, ST1a, and ST1b by RT-PCR assay were 0.1 to1.0 pg/μL and by conventional PCR assay were 100 to1000 pg/μL. The accuracy, rapidity and sensitivity of this RT-PCR assay is promising for ETEC detection in public health/clinical laboratories and for laboratories in need of an independent method to confirm results of other culture independent diagnostic tests.
- Structural Insights into the Fluoroquinolone Resistance Mechanism of Shigella flexneri DNA Gyrase and Topoisomerase IV. [JOURNAL ARTICLE]
- Microb Drug Resist 2016 Feb 9.
Traveler's diarrhea (TD) is an important public health concern that can result from a variety of intestinal pathogens, including bacteria, parasites, and virus. A number of antibiotics are being used to cure TD, but due to widespread use of these antibiotics, the pathogens are becoming resistant to them. In this work, we performed docking studies of DNA gyraseA (GyrA) and topoisomerase IV (ParC) of Shigella flexneri and their mutants with two different fluoroquinolones, ciprofloxacin and norfloxacin, to understand their resistance mechanism at the structural level. S. flexneri strains with mutations at serine 83 to leucine and aspartic acid 87 to glutamate or asparagine of GyrA and that of serine 80 to isoleucine in ParC have decreased susceptibility to fluoroquinolones. This analysis revealed that interaction of ciprofloxacin/norfloxacin with all the mutants was weaker than the interaction of ciprofloxacin/norfloxacin with the wild type. This study highlights the importance of aspartic acid and serine in GyrA and that of serine in ParC, forming bonds with ciprofloxacin/norfloxacin, which may play a crucial role in antibiotic resistance. This work corelates very well with the experimental outcomes and gives a good explanation for fluoroquinolone resistance in S. flexneri.
- [Diagnostic workup and therapy of infectious diarrhea. Current standards]. [English Abstract, Journal Article]
- Internist (Berl) 2015 Dec; 56(12):1353-60.
Infectious diarrhea is very common; its severity ranges from uncomplicated, self-limiting courses to potentially life-threatening disease. A rapid diagnostic workup providing detailed information on the suspected pathogen should be performed only in patients at risk, analyzing one single stool sample for Salmonella, Shigella, Campylobacter, and Norovirus. In the presence of risk factors, such as a history of antibiotic exposure within the last 3 months, testing for Clostridium difficile should be performed. Immunocompetent patients do not require specific antibiotic therapy. Exceptions exist in patients with severe comorbidities, immunodeficiency, fever/SIRS, and in patients with Shigella or C. difficile infection. Empirical antibiotic treatment should be considered in patients with fever and/or bloody diarrhea and in patients at risk. In patients with traveler's diarrhea, microbiological diagnosis is required only in patients with fever, bloody diarrhea, prolonged course of disease (more than 5 days), severe clinical course with hypotension or dehydration, and during outbreaks. In these patients one single fecal sample should be collected for stool cultures of Campylobacter, Shigella, and Salmonella, as well as microscopic examination for amoebiasis and Giardiasis. The main therapeutic measure for infectious diarrhea is sufficient oral rehydration. As in community-acquired diarrhea, azithromycin or ciprofloxacin are recommended-taking into account local antimicrobial resistance in the country of travel and possible side effects.