Eigaard N M, Permin A, Christensen J P, Bojesen A M, Bisgaard M
Department of Veterinary Pathobiology, The Royal Veterinary and Agricultural University, Stigbøjlen 4, DK-1870, Frederiksberg C, Denmark.
Avian Pathol. 2006 Apr;35(2):165-72. doi: 10.1080/03079450600598186.
Detailed longitudinal studies of the genetic stability of Pasteurella multocida ssp. multocida, the cause of fowl cholera, have not previously been carried out. Consequently, the aim of the present study was to provide detailed information on the genetic stability and diversity of P. multocida ssp. multocida in poultry flocks over time, enabling new insights into the molecular epidemiology of this important poultry pathogen. Longitudinal investigations of the rate and causes of mortality were carried out on two free-range layer farms (A and B) over a period of 11 months. The total mortality of two flocks, A1 and A2, on farm A were 62 and 91%, respectively, while the total mortality of a single flock B1 on farm B was 6%. Postmortem examinations were performed on 708 layers from flocks A1 and A2 and in 159 from flock B1. Fowl cholera was the main cause of mortality on both farms. Pasteurella multocida isolates recovered from layers on both farms were characterized phenotypically and genotypically, and 322 isolates were identified as P. multocida ssp. multocida. The genetic diversity of 99 isolates from farm A and 31 from farm B was characterized by restriction endonuclease analysis and amplified fragment length polymorphism analysis. The isolates on each farm had a unique restriction endonuclease analysis and amplified fragment length polymorphism analysis type, suggesting a single introduction of a successful clone. Furthermore the clone on farm A was identical to clones previously isolated from outbreaks in the avifauna of Denmark in 1996 and 2001 and in Sweden in 1998. This study provides convincing evidence for the clonal stability of outbreak clones of P. multocida.
此前尚未对禽霍乱病原体多杀巴斯德氏菌多杀亚种的遗传稳定性进行详细的纵向研究。因此,本研究的目的是提供多杀巴斯德氏菌多杀亚种在禽类群体中随时间变化的遗传稳定性和多样性的详细信息,以便对这种重要的家禽病原体的分子流行病学有新的认识。在11个月的时间里,对两个自由放养蛋鸡场(A和B)的死亡率及其原因进行了纵向调查。农场A中A1和A2两个鸡群的总死亡率分别为62%和91%,而农场B中单个鸡群B1的总死亡率为6%。对来自鸡群A1和A2的708只蛋鸡以及鸡群B1的159只蛋鸡进行了尸检。禽霍乱是两个农场死亡率的主要原因。对从两个农场的蛋鸡中分离出的多杀巴斯德氏菌进行了表型和基因型特征分析,共鉴定出322株分离株为多杀巴斯德氏菌多杀亚种。通过限制性内切酶分析和扩增片段长度多态性分析对来自农场A的99株分离株和来自农场B的31株分离株的遗传多样性进行了特征分析。每个农场的分离株都有独特的限制性内切酶分析和扩增片段长度多态性分析类型,表明成功克隆是单次引入的。此外,农场A的克隆与1996年和2001年在丹麦以及1998年在瑞典的鸟类疫情中先前分离出的克隆相同。本研究为多杀巴斯德氏菌疫情克隆的克隆稳定性提供了令人信服的证据。