Best Angus, La Ragione Roberto M, Cooley William A, O'Connor C David, Velge Phillipe, Woodward Martin J
Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7BX, UK.
Vet Microbiol. 2003 May 29;93(3):207-22. doi: 10.1016/s0378-1135(03)00031-2.
The prevalence of Escherichia coli O157:H7 infection in birds is low but several deliberate inoculation studies show that poultry are readily and persistently infected by this organism indicating a possible threat to public health. The mechanisms of colonisation of poultry are not understood and the aim is to establish models to study the interaction of E. coli O157:H7, at the cellular and whole animal levels. A non-toxigenic E. coli O157:H7 (NCTC 12900) was used in adherence assays with an avian epithelial cell line (Div-1) and used to inoculate 1-day-old SPF chicks. In vitro, NCTC 12900 induced micro-colonies associated with cytoskeletal arrangements and pedestal formation with intimate bacterial attachment. In the 1-day-old SPF chick, a dose of 1 x 10(5) cfu resulted in rapid and extensive colonisation of the gastrointestinal tract and transient colonisation of the liver and spleen. The number of E. coli O157:H7 organisms attained approximately 10(8) cfu/ml caecal homogenate 24h after inoculation and approximately 10(7) cfu/ml caecal homogenate was still present at day 92. Faecal shedding persisted for 169 days, ceasing 9 days after the birds came into lay and 6% of eggs were contaminated on the eggshell. Histological analysis of tissue samples from birds dosed with 1x10(7) cfu gave evidence for E. coli O157:H7 NCTC 12900 induced micro-colonies on the caecal mucosa, although evidence for attaching effacing lesions was equivocal. These models may be suitable to study those factors of E. coli O157:H7 that mediate persistent colonisation in avian species.
鸟类中大肠杆菌O157:H7感染的发生率较低，但多项人工接种研究表明，家禽很容易被这种微生物持续感染，这对公众健康构成了潜在威胁。目前尚不清楚家禽的定植机制，目的是建立模型，在细胞和全动物水平上研究大肠杆菌O157:H7的相互作用。一株非产毒大肠杆菌O157:H7（NCTC 12900）用于与一种禽类上皮细胞系（Div-1）进行黏附试验，并用于接种1日龄的无特定病原体（SPF）雏鸡。在体外，NCTC 12900诱导形成与细胞骨架排列和基座形成相关的微菌落，细菌紧密附着。在1日龄的SPF雏鸡中，1×10⁵ cfu的剂量导致胃肠道迅速广泛定植，肝脏和脾脏短暂定植。接种后24小时，盲肠匀浆中大肠杆菌O157:H7的数量达到约10⁸ cfu/ml，在第92天时仍有约10⁷ cfu/ml的盲肠匀浆。粪便排菌持续了169天，在母鸡开始产蛋后9天停止，6%的鸡蛋蛋壳被污染。对接种1×10⁷ cfu的鸟类组织样本进行组织学分析，发现盲肠黏膜上有大肠杆菌O157:H7 NCTC 12900诱导形成的微菌落，尽管关于紧密黏附损伤的证据并不明确。这些模型可能适合研究介导禽类持续定植的大肠杆菌O157:H7的那些因素。
