Herzberg M C, MacFarlane G D, Gong K, Armstrong N N, Witt A R, Erickson P R, Meyer M W
Department of Preventive Sciences, School of Dentistry, University of Minnesota, Minneapolis 55455.
Infect Immun. 1992 Nov;60(11):4809-18. doi: 10.1128/iai.60.11.4809-4818.1992.
A strain of Streptococcus sanguis that induced rabbit platelets to aggregate in vitro (Agg+ phenotype) was hypothesized to be a more virulent pathogen than an Agg- strain in experimental endocarditis in rabbits. A left ventricular catheter was implanted, and then an Agg+ or Agg- strain was inoculated intravenously. Vegetations formed on the aortic semilunar valves but were unaffected by the duration of implantation of the catheter. Vegetations enlarged by accumulating platelets and their mass increased directly with the duration of endocarditis. Inoculation of the Agg+ strain consistently caused endocarditis with significantly larger vegetations, a more severe clinical course (including febrile episodes, hematological changes, and signs of myocardial ischemia), more gross lesions in major organs, and greater mortality than inoculation with the Agg- strain, saline, or the Agg+ strain pretreated with monospecific rabbit immunoglobulin G or Fab fragments against its platelet aggregation-associated protein (PAAP; class II). In experimental endocarditis, PAAP expressed by Agg+ S. sanguis appeared to be an important virulence factor.
一种在体外能诱导兔血小板聚集的血链球菌菌株（Agg+表型）被推测在兔实验性心内膜炎中比Agg-菌株更具致病性。植入左心室导管，然后静脉接种Agg+或Agg-菌株。赘生物在主动脉半月瓣上形成，但不受导管植入时间的影响。赘生物通过血小板聚集而增大，其质量随心内膜炎持续时间直接增加。与接种Agg-菌株、生理盐水或用针对其血小板聚集相关蛋白（PAAP；II类）的单特异性兔免疫球蛋白G或Fab片段预处理的Agg+菌株相比，接种Agg+菌株始终导致心内膜炎，赘生物明显更大，临床病程更严重（包括发热发作、血液学变化和心肌缺血体征），主要器官出现更多肉眼可见病变，死亡率更高。在实验性心内膜炎中，Agg+血链球菌表达的PAAP似乎是一种重要的毒力因子。
