Mycoplasma ovipneumoniae can predispose bighorn sheep to fatal Mannheimia haemolytica pneumonia
Mycoplasma ovipneumoniae can predispose bighorn sheep to fatal Mannheimia haemolytica pneumonia
复制标题
DOI：
10.1016/j.vetmic.2010.04.011
复制
发表时间：
2010-10-26
影响因子：
3.3
通讯作者：
Srikumaran, Subramaniam
中科院分区：
文献类型：
--
作者：
Dassanayake, Rohana P.;Shanthalingam, Sudarvili;Srikumaran, Subramaniam
绵羊肺炎支原体已从患肺炎的大角羊（BHS）的肺中分离出来。然而，在BHS中用M实验重现了致命性肺炎。绵羊肺炎没有成功。因此，具体的作用，如果有的话，M。绵羊肺炎在BHS肺炎中的作用尚不清楚。本研究的目的是确定是否M。绵羊肺炎单独引起BHS的致命性肺炎，或使它们易于被溶血性曼氏菌感染。我们选择了M。溶血性BHS，因为它从肺炎BHS中分离出来，并且在实验条件下具有引起致死性肺炎的一致能力。由于体外培养可使M.在绵羊肺炎中，我们使用来自肺炎BHS羔羊的头孢噻呋处理的肺匀浆或来自绵羊肺炎支原体的鼻咽冲洗液。绵羊肺炎支原体阳性的家绵羊（DS）是M.绵羊肺炎。两个成年BHS鼻内接种肺匀浆，而另两个人接受了从DS鼻咽冲洗。所有BHS都出现了呼吸道感染的临床体征，但只有一名BHS死亡。死亡的BHS携带白细胞毒素阳性的M。在本研究开始之前，鼻咽部存在溶血性。很可能M。绵羊肺炎菌的定植使该BHS易于受到M.已经存在于该动物中的溶血性病原体。其余3只BHS在鼻内接种M后1-5天发生肺炎并死亡。溶血性尸检时，所有4只BHS的肺部均显示支气管肺炎特征性病变。M. haemolytica和M.绵羊肺炎分离自肺。这些结果表明M.在BHS中，单独的绵羊肺炎可能不会引起致命性肺炎，但可能使它们易于发生由M.溶血性感染(C)2010爱思唯尔有限公司版权所有。
Mycoplasma ovipneumoniae has been isolated from the lungs of pneumonic bighorn sheep (BHS). However experimental reproduction of fatal pneumonia in BHS with M. ovipneumoniae was not successful. Therefore the specific role, if any, of M. ovipneumoniae in BHS pneumonia is unclear. The objective of this study was to determine whether M. ovipneumoniae alone causes fatal pneumonia in BHS, or predisposes them to infection by Mannheimia haemolytica. We chose M. haemolytica for this study because of its isolation from pneumonic BHS, and its consistent ability to cause fatal pneumonia under experimental conditions. Since in vitro culture could attenuate virulence of M. ovipneumoniae, we used ceftiofur-treated lung homogenates from pneumonic BHS lambs or nasopharyngeal washings from M. ovipneumoniae-positive domestic sheep (DS) as the source of M. ovipneumoniae. Two adult BHS were inoculated intranasally with lung homogenates while two others received nasopharyngeal washings from DS. All BHS developed clinical signs of respiratory infection, but only one BHS died. The dead BHS had carried leukotoxin-positive M. haemolytica in the nasopharynx before the onset of this study. It is likely that M. ovipneumoniae colonization predisposed this BHS to fatal infection with the M. haemolytica already present in this animal. The remaining three BHS developed pneumonia and died 1-5 days following intranasal inoculation with M. haemolytica. On necropsy, lungs of all four BHS showed lesions characteristic of bronchopneumonia. M. haemolytica and M. ovipneumoniae were isolated from the lungs. These results suggest that M. ovipneumoniae alone may not cause fatal pneumonia in BHS, but can predispose them to fatal pneumonia due to M. haemolytic infection. (C) 2010 Elsevier B.V. All rights reserved.