Shiro H, Muller E, Gutierrez N, Boisot S, Grout M, Tosteson T D, Goldmann D, Pier G B
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
J Infect Dis. 1994 May;169(5):1042-9. doi: 10.1093/infdis/169.5.1042.
Virulence comparisons were made in a rabbit model of endocarditis between wild-type and transposon mutants of Staphylococcus epidermidis deficient in elaboration of the capsular polysaccharide/adhesin (PS/A) and slime. The parental phenotype grew from 36 (61%) of 59 cultures of blood. The PS/A-negative phenotype grew in 1 (1%) of 98 cultures of blood (P < .001). No animals infected with PS/A-negative strains developed endocarditis compared with 75% of rabbits infected with PS/A-positive strains. PS/A-producing strains survived better than did PS/A-deficient strains in intact, absorbed rabbit or human serum plus human leukocytes. There was also greater deposition of C3 onto the PS/A-deficient strains than with the PS/A-producing isogenic strains. PS/A functions as an antiphagocytic bacterial capsule preventing C3 deposition and phagocytosis; loss of this structure increases the strain's susceptibility to opsonic killing and decreases its virulence.
在兔心内膜炎模型中，对表皮葡萄球菌的野生型菌株与缺乏荚膜多糖/黏附素（PS/A）和黏液形成能力的转座子突变体进行了毒力比较。亲本表型在59份血培养物中有36份（61%）生长。PS/A阴性表型在98份血培养物中有1份（1%）生长（P <.001）。与感染PS/A阳性菌株的兔子中75%发生心内膜炎相比，没有感染PS/A阴性菌株的动物发生心内膜炎。在完整的、吸收后的兔或人血清加人白细胞中，产生PS/A的菌株比缺乏PS/A的菌株存活得更好。与产生PS/A的同基因菌株相比，C3在PS/A缺陷菌株上的沉积也更多。PS/A作为一种抗吞噬细菌荚膜，可防止C3沉积和吞噬作用；这种结构的丧失增加了菌株对调理吞噬杀伤的敏感性并降低了其毒力。
