PDF(Pubmed)
Abstract：
Colisepticaemia caused by avian pathogenic Escherichia coli (APEC) is a challenging disease due to its high economic importance in poultry, dubious pathogenesis and potential link with zoonosis and food safety. The existing in vitro studies can\'t define hallmark traits of APEC isolates, suggesting a paradigm shift towards host response to understand pathogenesis. This study investigated the comprehensive pathological and microbial progression of colisepticaemia, and transmission of E. coli into eggs using novel tools. In total 48 hens were allocated into three groups and were inoculated intratracheally with ilux2-E. coli PA14/17480/5-/ovary (bioluminescent strain), E. coli PA14/17480/5-/ovary or phosphate buffered saline. Infection with both strains led to typical clinical signs and lesions of colibacillosis as in field outbreaks. Based on lung histopathology, colisepticaemia progression was divided into four disease stages as: stage I (1-3 days post infection (dpi)), stage II (6 dpi), stage III (9 dpi) and stage IV (16 dpi) that were histologically characterized by predominance of heterophils, mixed cells, pyogranuloma, and convalescence, respectively. As disease progressed, bacterial colonization in host organs also decreased, revealed by the quantification of bacterial bioluminescence, bacteriology, and quantitative immunohistochemistry. Furthermore, immunofluorescence, immunohistochemistry, and bacteria re-isolation showed that E. coli colonized the reproductive tract of infected hens and reached to egg yolk and albumen. In conclusion, the study provides novel insights into the pathogenesis of colisepticemia by characterizing microbial and pathological changes at different disease stages, and of the bacteria transmission to table eggs, which have serious consequences on poultry health and food safety.
摘要：
由禽致病性大肠杆菌（APEC）引起的大肠杆菌性贫血是一种具有挑战性的疾病，因为它在家禽中具有很高的经济重要性，可疑的发病机理以及与人畜共患病和食品安全的潜在联系。现有的体外研究无法确定APEC分离株的标志性特征，提示向宿主反应的范式转变，以理解发病机理。这项研究调查了结肠炎的综合病理和微生物进展，使用新工具将大肠杆菌传播到鸡蛋中。将48只母鸡分为三组，并在气管内接种ilux2-E。大肠杆菌PA14/17480/5-/卵巢（生物发光菌株），大肠杆菌PA14/17480/5-/卵巢或磷酸盐缓冲盐水。与野外爆发一样，两种菌株的感染均导致大肠杆菌病的典型临床体征和病变。根据肺组织病理学，大肠杆菌血症的进展分为四个疾病阶段：I期（感染后1-3天（DPI）），第二阶段（6dpi），III期（9dpi）和IV期（16dpi），组织学特征是异源性粒细胞占优势，混合细胞，脓性肉芽肿,和恢复期，分别。随着疾病的发展,宿主器官中的细菌定植也减少了，通过细菌生物发光的定量揭示，细菌学，和定量免疫组织化学。此外，免疫荧光，免疫组织化学，细菌的重新分离表明，大肠杆菌定植于感染母鸡的生殖道，并到达蛋黄和蛋白。总之,该研究通过表征不同疾病阶段的微生物和病理变化，为大肠杆菌血症的发病机制提供了新的见解，以及细菌传播到食用鸡蛋的情况，对家禽健康和食品安全造成严重后果。
