Enterotoxigenic Escherichia coli in Developing Countries: Epidemiology, Microbiology, Clinical Features, Treatment, and Prevention

International Centre for Diarrhoeal Disease Research, Bangladesh.
Clinical Microbiology Reviews (Impact Factor: 17.41). 08/2005; 18(3):465-83. DOI: 10.1128/CMR.18.3.465-483.2005
Source: PubMed


ETEC is an underrecognized but extremely important cause of diarrhea in the developing world where there is inadequate clean water and poor sanitation. It is the most frequent bacterial cause of diarrhea in children and adults living in these areas and also the most common cause of traveler's diarrhea. ETEC diarrhea is most frequently seen in children, suggesting that a protective immune response occurs with age. The pathogenesis of ETEC-induced diarrhea is similar to that of cholera and includes the production of enterotoxins and colonization factors. The clinical symptoms of ETEC infection can range from mild diarrhea to a severe cholera-like syndrome. The effective treatment of ETEC diarrhea by rehydration is similar to treatment for cholera, but antibiotics are not used routinely for treatment except in traveler's diarrhea. The frequency and characterization of ETEC on a worldwide scale are inadequate because of the difficulty in recognizing the organisms; no simple diagnostic tests are presently available. Protection strategies, as for other enteric infections, include improvements in hygiene and development of effective vaccines. Increases in antimicrobial resistance will dictate the drugs used for the treatment of traveler's diarrhea. Efforts need to be made to improve our understanding of the worldwide importance of ETEC.

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    • "Although it can be harmless, ETEC is considered one of the most common pathogens, causing diarrhea among travelers and children in developing countries. Infection is normally associated with the presence of ETEC in contaminated food or water (Qadri et al., 2005; Zhang et al., 2008). The evaluation of this pathogen's presence in food sources is becoming an increasingly important issue in human health. "
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    ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) is the major pathogen responsible for neonatal diarrhea, postweaning diarrhea, and edema disease in pigs. Although it can be harmless, ETEC is also present in the intestines of other animal species and humans, causing occasional diarrhea outbreaks. The evaluation of this pathogen's presence in food sources is becoming an increasingly important issue in human health. In order to determine the prevalence of ETEC in nondiarrheic pigs, 990 animals from 11 pig farms were sampled. Using end-time polymerase chain reaction (PCR), eltA, estI genes, or both, were detected in 150 (15.2%) animals. From the positive samples, 40 (26.6%) ETEC strains were isolated, showing 19 antibiotic-resistance patterns; 52.5% of these strains had multiple antibiotic resistances, and 17.5% carried the intI2 gene. The most prevalent genotypes were rfbO157/estII/aidA (32.5%) and estI/estII (25.0%). The estII gene was identified most frequently (97.5%), followed by estI (37.5%), astA (20.0%), and eltA (12.5%). The genes coding the fimbriae F5, F6, and F18 were detected in three single isolates. The aidA gene was detected in 20 ETEC strains associated with the estII gene. Among the isolated ETEC strains, stx2e/estI, stx2e/estI/estII, and stx2e/estI/estII/intI2 genotypes were identified. The ETEC belonged to 12 different serogroups; 37.5% of them belonged to serotype O157:H19. Isolates were grouped by enterobacterial repetitive intergenic consensus-PCR into 5 clusters with 100.0% similarity. In this study, we demonstrated that numerous ETEC genotypes cohabit and circulate in swine populations without clinical manifestation of neonatal diarrhea, postweaning diarrhea, or edema disease in different production stages. The information generated is important not only for diagnostic and epidemiological purposes, but also for understanding the dynamics and ecology of ETEC in pigs in different production stages that can be potentially transmitted to humans from food animals.
    Foodborne Pathogens and Disease 07/2015; 12(8). DOI:10.1089/fpd.2015.1959 · 1.91 Impact Factor
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    • "Enterotoxigenic Escherichia coli (ETEC) pathotypes are a major cause of infantile watery diarrhea in developing countries as well as in travellers globally (Qadri et al. 2005). They are defined by the presence of a heat-labile toxin and/or a heat-stable toxin (Nataro and Kaper 1998). "
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    ABSTRACT: Enterotoxigenic Esherichia coli strains harbour multiple fimbriae and pili to mediate host colonization, including the type IVb pilus, colonization factor antigen III (CFA/III). Not all colonization factors (CFs) are well characterised or known in toxin positive ETEC isolates, which may have an impact identifying ETEC isolates based on molecular screening of these biomarkers. We describe a novel coli surface antigen (CS) 8 subtype B (CS8B), a family of CFA/III pilus, in a toxin producing ETEC isolate from a Kenyan collection. In highlighting the existence of this putative CS we provide the sequence and specific primers, which can be used alongside other ETEC primers previously described. © FEMS 2015.
    Pathogens and Disease 07/2015; 73(7). DOI:10.1093/femspd/ftv047 · 2.40 Impact Factor
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    • "They are facultative anaerobes, capable of mixed-acid fermentation under anaerobic conditions, and are a ubiquitous commensal organism present in the gut of endothermic animals. Although most strains are non-pathogenic, certain virulent serotypes, such as ETEC and EPEC, have emerged in recent years [23] [24], and the spread of their associated pathogenic elements has accelerated due to the natural competence of the organisms – a feature which has facilitated their widespread use in molecular biology and fermentation laboratories [30]. Infection is often by the faecal–oral route, and although infection in developed countries is often due to contaminated food, contaminated water is still a major reservoir of infection in regions such as Africa, where an estimated 345 million people are still unable to access clean drinking water [2] [21]. "
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    ABSTRACT: Despite the increasing use of Decentralised Waste Water Systems (DEWATS) in the developing world, which effectively dewater sludge, the problem of preventing the pathogen-laden water produced by these systems from re-entering the food chain constitutes a continuing burden on developing countries, which hinders subsequent advancements. We report on a swirl flow reactor generating high mixing areas which in conjunction with Cu/alginate beads effectively reduces Escherichia coli numbers by five orders of magnitude in 10 min. The system is simple, low cost, portable and modular; it can be assembled with simple plastic plumbing parts available in most areas and, once further developed, may represent a useful adjunct for both existing and new DEWATS facilities.
    Journal of Water Process Engineering 04/2015; 5:6-14. DOI:10.1016/j.jepe.2014.10.010
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