禽波氏菌强毒株感染雏鸡呼吸系统荷菌量及病变规律的研究

Study on Colonization and Pathological Changes of Chick Respiratory Tract Induced by Bordetella avium Virulent Isolate

禽波氏菌为产碱杆菌科波氏杆菌属成员,主要导致咳嗽等呼吸道症状。为探索禽波氏菌经呼吸道的入侵过程及其病变发生发展规律,本试验利用筛选到的强毒株经鼻腔感染SPF雏鸡,在感染后的不同时间检测气管和肺荷菌量的变化,通过扫描电镜观察禽波氏菌在气管的定植及其病变规律,利用间接免疫酶组化研究禽波氏菌在肺中的定植规律,分析肺和支气管的病理组织学变化。结果发现,在感染之初气管中细菌数量较多,而肺中较少,之后气管和肺的荷菌量均呈明显上升趋势。感染后1d即发现禽波氏菌已经在气管纤毛上定植,且纤毛开始出现脱落;到5d时气管黏膜表面呈斑驳状,纤毛大面积脱落,甚至出现空洞。肺在感染后2d检测出细菌定植,主要分布在肺房和呼吸毛细管壁的细胞质中,之后随着感染时间的延长,阳性信号不断增加。肺和支气管的病理变化在5d时出现,主要表现淤血;至感染后10d,大量细胞坏死。试验结果表明所筛选禽波氏菌分离株对雏鸡的呼吸道具有很强的亲嗜性,优先定植于气管上皮细胞的纤毛上,并随之在气管、支气管和肺产生一系列的组织病理学变化。

Bordetella avium（B.avium）,one of the members of Bordetella genus,Alcaligenes Branch,mainly causes birds cough and other respiratory symptoms.To explore its invasive procedure by respiratory tract and regular pattern of lesions development,SPF chicks were challenged by nasal infection with a screened virulent B.aviumstrain.After infection,bacteria quantity in trachea and lungs were detected at different times.Tracheas colonization and lesions were observed by SEM.Lungs colonization pattern were detected by indirect immunoenzymatic staining.Histopathological changes in lung and bronchus were detected by pathological examination.It was found that bacterial infection of the trachea was in larger quantities,and only a small amount in the lungs at the beginning.And then the amount of bacteria in trachea and lungs showed a clear upward trend.B.avium had colonized on the cilia of trachea,and cilia began to fall off on 1dafter infection.To 5dafter infection,tracheal mucosal surface mottled,cilia fell off in a large area,and even holes appeared.Lungs colonization were detected on 2dafter infection,and B.avium were mainly distributed in the cytoplasm of lung housing and respiratory cap-illary walls.Positive signals were increasing with the extension of time.Pathological changes in the lungs and bronchi appeared on 5dafter infection,mainly showed congestion.To 10 dafter infection,a large number of cell necrosis appeared.In conclusion,this B.aviumisolate has a strong tropism on chick respiratory tract.Especially it has priority colonization on cilia of tracheal epithelial cells,and subsequently causes a series of histopathological changes in the trachea,bronchi and lungs.