Mycoplasma bovis-associated suppurative otitis media and pneumonia in bull calves
Mycoplasma bovis-associated suppurative otitis media and pneumonia in bull calves
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DOI：
10.1016/s0021-9975(03)00009-4
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发表时间：
2003-08-01
影响因子：
0.8
通讯作者：
Kadota, K
中科院分区：
文献类型：
--
作者：
Maeda, T;Shibahara, T;Kadota, K
2000年至2001年期间，在日本北海道的四个肉牛养殖场暴发了牛支原体相关中耳炎和肺炎。发病率和死亡率估计分别为8- 40%和30-100%。对8例双耳下垂、渗出性中耳炎患儿进行了细菌学和组织病理学检查。牛分枝杆菌是在死后从所有小牛的鼻拭子以及耳朵、肺、淋巴结（颅和肺）、大脑和心脏中分离出来的。所有病例尸检均见鼓室大泡化脓性渗出物。在7例颞骨及肺的岩部也发现大量脓肿。组织病理学上，鼓室大泡内渗出物由中性粒细胞、坏死细胞碎片和纤维蛋白混合组成，鼓室黏膜增厚，中性粒细胞和巨噬细胞浸润，纤维结缔组织增生。肺部病变包括广泛的凝固性坏死灶，周围有大量的中性粒细胞。肝细胞或肾小管上皮细胞增大，可见透明质包涵体。免疫组织化学标记证实在中耳、颞骨和肺的炎症细胞的细胞质中存在牛支原体抗原，并且在肝细胞和肾小管上皮细胞的细胞质包涵体中也发现了牛支原体抗原。超微结构上，支原体样生物，直径200-500微米，不仅在肝细胞和肾小管上皮内，而且在面神经的轴突内发现。目前的研究结果表明，牛分枝杆菌可扩散到多个器官，并能侵入多种宿主细胞。细胞内定位可能有利于逃避宿主免疫应答。(C) 2003 Elsevier Ltd.版权所有。
Outbreaks of Mycoplasma bovis-associated otitis media and pneumonia occurred on four beef cattle farms in Hokkaido, Japan between 2000 and 2001. The morbidity and mortality were estimated at 8-40 and 30-100%, respectively. Eight calves with bilateral ear droop and exudative otitis media were examined bacteriologically and histopathologically. M. bovis was isolated post mortem from nasal swabs and from the ears, lungs, lymph nodes (cranial and pulmonary), brain and heart of all calves. At necropsy, suppurative exudates were observed in the tympanic bullae of all cases. Numerous abscesses were also found in the petrous portion of the temporal bone and lungs in seven cases. Histopathologically, the exudates within the tympanic bullae consisted of a mixture of neutrophils, necrotic cell debris and fibrin, and the tympanic mucosa was thickened with neutrophil and macrophage infiltration and proliferation of fibrous connective tissue. Pulmonary lesions included extensive foci of coagulative necrosis surrounded by numerous neutrophils. Hepatocytes or renal tubular epithelial cells were enlarged with hyaline cytoplasmic inclusions in four calves. Immunohistochemical labelling confirmed the presence of M. bovis antigen in the cytoplasm of the inflammatory cells in the middle ear, temporal bone and lungs, and was also demonstrated within the cytoplasmic inclusions of the hepatocytes and renal tubular epithelial cells. Ultrastructurally, mycoplasma-likc organisms, 200-500 mum in diameter, were found within not only hepatocytes and renal tubular epithelia but also within axons of the facial nerves. The present results show that M. bovis spreads to multiple organs and is capable of invading various kinds of host cell. The intracellular localization may be favourable for evading host immune responses. (C) 2003 Elsevier Ltd. All rights reserved.