a Zoonotic Infections of People, Pigs and Poultry Group , Institute of Infection & Global Health and School of Veterinary Science, University of Liverpool , Leahurst Campus, Neston , UK.
Avian Pathol. 2014;43(1):37-42. doi: 10.1080/03079457.2013.866213. Epub 2013 Dec 16.
Avian pathogenic Escherichia coli (APEC) are a substantial burden to the global poultry industry. APEC cause a syndromic poultry infection known as colibacillosis, which has been previously associated with broiler chickens over 2 weeks old. We recently reported that the intestinal tract of 1-day-old broilers harbours a rich reservoir of potentially pathogenic E. coli. Prior infections of the reproductive tract of breeders, egg hygiene and transportation all contribute to early colonization of the neonatal gut. Up to one-half of all flock deaths occur in the first week of production, but few data are available describing the contribution of E. coli. In the present study, all dead birds collected on the first daily welfare walk 48 and 72 h after chick placement underwent post-mortem examination. Diseased tissues were selectively cultured for E. coli and isolates subsequently virulotyped using 10 APEC virulence-associated genes (VAGs): astA, iss, irp2, iucD, papC, tsh, vat, cvi, sitA and ibeA. Approximately 70% of birds displayed signs of colibacillosis. Thirty distinct virulence profiles were identified among 157 E. coli. Isolates carried between zero and seven VAGs; ∼ 30% of E. coli isolates carried five to seven VAGs, with 12.7% sharing the same VAG profile (astA, iss, irp2, iucD, tsh, cvi and sitA). Overall, this study demonstrates the significant contribution of E. coli infections to early broiler mortalities. The identification of a diverse E. coli population is unsurprising based on our previous findings. This work emphasizes the need for an effective vaccination programme and provides preliminary data for vaccine production.
禽致病性大肠杆菌（APEC）是全球家禽业的重大负担。APEC 引起一种称为大肠杆菌病的综合征性家禽感染，以前与 2 周龄以上的肉鸡有关。我们最近报道，1 日龄肉鸡的肠道中存在丰富的潜在致病性大肠杆菌。种鸡生殖道的先前感染、蛋的卫生和运输都有助于新生肠道的早期定植。高达一半的鸡群死亡发生在生产的第一周，但很少有数据描述大肠杆菌的贡献。在本研究中，在雏鸡放置后 48 和 72 小时进行的第一次日常福利步行期间收集的所有死亡鸟类都进行了尸检。选择对患病组织进行大肠杆菌培养，随后使用 10 种 APEC 毒力相关基因（VAG）对分离株进行毒力定型：astA、iss、irp2、iucD、papC、tsh、vat、cvi、sitA 和 ibeA。大约 70%的鸟类表现出大肠杆菌病的症状。在 157 株大肠杆菌中鉴定出 30 种不同的毒力谱。分离株携带 0 到 7 个 VAG；约 30%的大肠杆菌分离株携带 5 到 7 个 VAG，其中 12.7%具有相同的 VAG 谱（astA、iss、irp2、iucD、tsh、cvi 和 sitA）。总体而言，这项研究表明大肠杆菌感染对早期肉鸡死亡率有重大贡献。基于我们之前的发现，鉴定出多样化的大肠杆菌种群并不令人惊讶。这项工作强调了有效疫苗接种计划的必要性，并为疫苗生产提供了初步数据。
