Enterotoxigenic Escherichia coli (ETEC) is the major etiological agent causing acute watery diarrhea that is most frequently seen in young children in lower-income countries. The duration of diarrheal symptom may be shortened by antibiotic treatment, but ETEC is relative refractory to common antibiotics. Burgeoning evidence suggests bioactive components that naturally occur in human milk (e.g., lysozyme and oligosaccharides) and plants (e.g., nondigestible carbohydrates and phytochemicals) contain antimicrobial functions are promising preventive measures to control ETEC infection. Although the exact protective mechanisms may vary for each compound and are still not completely understood, they generally act to (1) competitively inhibit the binding of pathogenic bacteria and toxins to gut epithelium; (2) directly kill pathogens; and (3) stimulate and/or enhance host mucosal and systemic immune defense against pathogenic microorganisms. An appropriate ETEC-challenge animal model is critical to evaluate the effect and unveil the mechanism of bioactive compounds in prevention of enteric infection. Despite wide application in biomedical research, rodents do not usually manifest typical clinical signs of enteric infections. The remarkable differences in digestive physiology, immune response, and gut microbiota between rodents and human beings necessitate the use of alternative animal models. Pigs are closely related to humans in terms of genomes, physiology, anatomy of gastrointestinal tracts, digestive enzymes, components of immune system, and gut microbiota. Like human infants and young children, nursing and nursery piglets are more susceptible to ETEC infection and reproduce the clinical signs as observed in humans. Hence, the ETEC-challenge piglet represents a valuable translational model to study pathogenesis and evaluate dietary factors (e.g., milk bioactive compounds, nondigestible carbohydrates, and phytochemicals) as preventive measures for ETEC infection in pediatrics.

中文翻译：

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预防小儿大肠杆菌感染的饮食因素：使用家猪的模型。

产肠毒素的大肠杆菌（ETEC）是引起急性水泻的主要病原体，在低收入国家的幼儿中最常见。腹泻症状的持续时间可以通过抗生素治疗来缩短，但是ETEC对普通抗生素是相对难治的。新兴的证据表明，天然存在于人乳中的生物活性成分（例如，溶菌酶和低聚糖）和植物（例如，不易消化的碳水化合物和植物化学物质）含有抗菌功能，有望成为控制ETEC感染的预防措施。尽管每种化合物的确切保护机制可能有所不同，但仍未完全了解，但它们通常起到以下作用：（1）竞争性抑制致病菌和毒素与肠道上皮的结合；（2）直接杀死病原体；（3）刺激和/或增强宿主对病原微生物的粘膜和全身免疫防御。合适的ETEC挑战动物模型对于评估效果并揭示生物活性化合物预防肠道感染的机制至关重要。尽管在生物医学研究中得到广泛应用，但是啮齿动物通常并不表现出肠感染的典型临床体征。啮齿动物和人类之间在消化生理，免疫反应和肠道菌群方面的显着差异使得必须使用替代动物模型。猪在基因组，生理，胃肠道解剖，消化酶，免疫系统组成和肠道菌群方面与人类密切相关。像人类婴幼儿一样，哺乳期和育苗期的仔猪更容易受到ETEC感染，并复制人类观察到的临床症状。因此，挑战ETEC的仔猪代表了一种有价值的转化模型，可用于研究发病机理并评估饮食因素（例如，牛奶中的生物活性化合物，不易消化的碳水化合物和植物化学物质），作为预防小儿ETEC感染的措施。