Nietfeld J C, Fickbohm B L, Rogers D G, Franklin C L, Riley L K
Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan 66506, USA.
J Vet Diagn Invest. 1999 May;11(3):252-8. doi: 10.1177/104063879901100308.
Filamentous, gram-negative bacteria morphologically similar to cilia-associated respiratory (CAR) bacillus of rodents and rabbits were isolated from the tracheas of 5 pigs and 4 calves. All pigs but none of the calves had histologic lesions of chronic tracheitis. In silver-stained histologic sections, CAR bacilli were adhered to the tracheal epithelium of each pig but were not found in the calves. Like CAR bacillus of rats, the bacteria displayed gliding motility and grew only in cell culture or cell culture medium supplemented with fetal serum. Initially, all isolates were contaminated by Mycoplasma spp. This contamination was eliminated from 4 pig isolates by limiting dilutions, and mycoplasma-free isolates were used to intranasally inoculate gnotobiotic pigs and CAR bacillus-free mice and rats and to immunize guinea pigs. The gnotobiotic pigs remained healthy, and when they were necropsied 4 and 7 weeks after infection no macroscopic or microscopic lesions were found in the respiratory tract. However, CAR bacillus was isolated at both times from the nasal cavities and tracheas of inoculated pigs, and the ciliated tracheal epithelium of infected pigs necropsied 7 weeks after infection was colonized by low numbers of CAR bacillus-like bacteria. The rats and mice remained healthy through week 12 postinoculation, and evidence of short- or long-term colonization was not detected by histologic examination or culture. When used as primary antibody for immunohistochemical staining, sera from guinea pigs immunized with pig CAR bacillus specifically stained CAR bacilli colonizing the respiratory epithelium of naturally infected pigs, whereas sera collected prior to immunization failed to react with the bacteria. These results indicate that CAR bacilli are unlikely to be primary pathogens of pigs or cattle and that rodents do not act as reservoirs.
从5头猪和4头小牛的气管中分离出丝状革兰氏阴性菌，其形态与啮齿动物和兔子的纤毛相关呼吸道（CAR）杆菌相似。所有猪都患有慢性气管炎的组织学病变，而小牛均未患病。在银染组织切片中，CAR杆菌附着在每头猪的气管上皮上，但在小牛中未发现。与大鼠的CAR杆菌一样，这些细菌表现出滑行运动能力，并且仅在添加胎牛血清的细胞培养物或细胞培养基中生长。最初，所有分离株均被支原体污染。通过有限稀释法从4株猪分离株中消除了这种污染，并用无支原体的分离株对无菌猪、无CAR杆菌的小鼠和大鼠进行鼻内接种，并免疫豚鼠。无菌猪保持健康，在感染后4周和7周进行尸检时，呼吸道未发现宏观或微观病变。然而，在接种猪的鼻腔和气管中两次均分离出CAR杆菌，感染后7周进行尸检的感染猪的纤毛气管上皮被少量CAR杆菌样细菌定植。大鼠和小鼠在接种后12周内保持健康，组织学检查或培养未检测到短期或长期定植的证据。当用作免疫组织化学染色的一抗时，用猪CAR杆菌免疫的豚鼠血清特异性地染色了自然感染猪呼吸道上皮中的CAR杆菌，而免疫前收集的血清则未与细菌发生反应。这些结果表明，CAR杆菌不太可能是猪或牛的主要病原体，并且啮齿动物不是其储存宿主。
