Confer A W, Panciera R J, Clinkenbeard K D, Mosier D A
Department of Veterinary Pathology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078.
Can J Vet Res. 1990 Apr;54 Suppl:S48-52.
Pasteurella haemolytica is represented by two biotypes (A and T), 15 serotypes, and numerous untypable strains. Specific biotypes and serotypes are associated with fibrinous pleuropneumonia (pneumonic pasteurellosis) in cattle, sheep, and goats, septicemic pasteurellosis in lambs, and mastitis in ewes. Four virulence factors have been associated with P. haemolytica: fimbriae, a polysaccharide capsule, endotoxin [lipopolysaccharide (LPS)], and leukotoxin (LKT). The interactions of these virulence factors with components of the pulmonary alveolus are discussed as a model for the pathogenesis of pasteurellosis. Fimbriae on P. haemolytica may enhance colonization of the upper respiratory tract. The capsule of P. haemolytica varies in composition among serotypes. It inhibits complement-mediated serum killing as well as phagocytosis and intracellular killing of P. haemolytica. The capsule enhances neutrophil directed migration and adhesion of P. haemolytica to alveolar epithelium. Pasteurella haemolytica LPS can alter bovine leukocyte functions, by dose-dependent inhibition or augmentation; it is directly toxic to bovine endothelium; it modifies cardiopulmonary hemodynamics; and it elevates circulatory prostanoids, serotonin, cAMP, and cGMP. Leukotoxin is produced by all known serotypes and many untypable strains. Leukotoxin is a poreforming cytolysin that affects ruminant leukocytes and platelets by altering function at low levels but causing lysis at high levels.
溶血巴斯德菌有两种生物型（A和T）、15个血清型以及众多无法分型的菌株。特定的生物型和血清型与牛、羊和山羊的纤维素性胸膜肺炎（肺炎型巴氏杆菌病）、羔羊的败血性巴氏杆菌病以及母羊的乳腺炎有关。已确定溶血巴斯德菌有四种毒力因子：菌毛、多糖荚膜、内毒素[脂多糖（LPS）]和白细胞毒素（LKT）。本文将讨论这些毒力因子与肺泡成分的相互作用，以此作为巴氏杆菌病发病机制的模型。溶血巴斯德菌的菌毛可能会增强其在上呼吸道的定植。溶血巴斯德菌的荚膜在不同血清型之间组成有所不同。它可抑制补体介导的血清杀伤作用以及对溶血巴斯德菌的吞噬和细胞内杀伤。荚膜可增强中性粒细胞的定向迁移以及溶血巴斯德菌与肺泡上皮的黏附。溶血巴斯德菌LPS可通过剂量依赖性抑制或增强作用来改变牛白细胞的功能；它对牛内皮细胞具有直接毒性；它可改变心肺血流动力学；并且它可提高循环中的前列腺素、血清素、环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）水平。所有已知血清型以及许多无法分型的菌株均可产生白细胞毒素。白细胞毒素是一种形成孔道的溶细胞素，它通过在低水平改变功能但在高水平导致裂解来影响反刍动物的白细胞和血小板。
