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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    • "Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of diarrheal disease in humans and animals (Zhu et al., 2011). ETEC is the most common cause of traveler's diarrhea and can be fatal for children (Qadri et al., 2005). The major virulence factors are bacterial fimbriae that mediate bacterial attachment to host enterocytes allowing its colonization and proliferation, and the production of enterotoxins, which stimulate fluid and electrolyte secretion by intestinal cells leading to diarrhea (Fairbrother et al., 2005). "
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    ABSTRACT: Quorum sensing (QS) is a signaling system among bacteria mediated by auto-inducer substances (AI). Whenever the concentration of these molecules reaches a threshold corresponding to a high cell density or quorum, the whole population starts a coordinated expression of specific genes. Studies have shown that epinephrine is also responsible for activating specific bacterial genes. This work aimed to investigate the role of conditioned medium (containing AI), epinephrine and their association on growth, motility, F4 fimbriae and heat-labile toxin (LT) expression on enterotoxigenic Escherichia coli (ETEC, E68). A significant increase in motility, F4 and LT expression, was observed in the ETEC culture supplemented with conditioned medium and epinephrine. These findings suggest that ETEC uses some components of conditioned medium (e.g., AI molecules), host molecules (epinephrine), and their association to modulate the expression of important virulence genes.
    Veterinary Microbiology 09/2015; DOI:10.1016/j.vetmic.2015.08.015 · 2.51 Impact Factor
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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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