Pfaff-McDonough S J, Horne S M, Giddings C W, Ebert J O, Doetkott C, Smith M H, Nolan L K
Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo 58105, USA.
Avian Dis. 2000 Jan-Mar;44(1):23-33.
In this study, 294 Escherichia coli isolates from birds with colibacillosis were collected from disease outbreaks throughout the United States and were compared with 75 fecal E. coli isolates of apparently healthy chickens by their possession of several purported virulence genes, resistance to rough-lipopolysaccharide-specific bacteriophages (rLPSr), and elaboration of capsule. Traits were selected for study on the basis of their association with complement resistance. The genes targeted in this study included those encoding colicin V (cvaC) and the outer membrane proteins TraT (traT), OmpA (ompA), and Iss (iss). No significant differences were found between the two groups of isolates in the occurrence of cvaC-, traT-, or ompA-homologous sequences or in rLPSr. Only a few isolates were encapsulated, and the isolates of healthy birds were significantly more likely to be encapsulated than were the isolates of sick birds. However, iss, whether detected through hybridization or amplification, was found in more of the disease-associated isolates than in those of healthy birds. This difference was highly significant. Further, iss sequences were widely distributed among isolates of different serotypes from various avian host species and sites within these hosts. Such results suggest that possession of the iss sequence by an avian E. coli isolate may be a good indicator of that isolate's potential to cause disease. This association warrants further study because iss and the protein it encodes may be useful targets of future colibacillosis control efforts.
在本研究中，从美国各地疾病暴发中收集了294株来自患大肠杆菌病禽类的大肠杆菌分离株，并与75株表面健康鸡的粪便大肠杆菌分离株进行比较，比较内容包括它们是否拥有几种所谓的毒力基因、对粗糙脂多糖特异性噬菌体（rLPSr）的抗性以及荚膜形成情况。基于与补体抗性的关联选择性状进行研究。本研究中靶向的基因包括编码大肠杆菌素V（cvaC）以及外膜蛋白TraT（traT）、OmpA（ompA）和Iss（iss）的基因。两组分离株在cvaC、traT或ompA同源序列的出现情况或rLPSr方面未发现显著差异。只有少数分离株形成荚膜，并且健康禽类的分离株比患病禽类的分离株更有可能形成荚膜。然而，无论是通过杂交还是扩增检测到的iss，在与疾病相关的分离株中比在健康禽类的分离株中出现得更多。这种差异非常显著。此外，iss序列在来自各种禽类宿主物种及这些宿主内不同部位的不同血清型分离株中广泛分布。这些结果表明，禽类大肠杆菌分离株拥有iss序列可能是该分离株致病潜力的良好指标。这种关联值得进一步研究，因为iss及其编码的蛋白质可能是未来大肠杆菌病防控工作的有用靶点。
