Dajcs Joseph J, Thibodeaux Brett A, Girgis Dalia O, O'Callaghan Richard J
Department of Microbiology, Immunology, and Parasitology, LSU Health Sciences Center in New Orleans, New Orleans, Louisiana 70112, USA.
DNA Cell Biol. 2002 May-Jun;21(5-6):375-82. doi: 10.1089/10445490260099656.
The aim of this study was to determine the pathogenic role of alpha-, beta-, and gamma-toxins in a rabbit model of Staphylococcus aureus keratitis. S. aureus strains 8325-4, Newman, and their isogenic mutants were intrastromally injected into rabbit corneas. Eyes were scored for pathology by slit lamp examination (SLE), histologic examination, and bacterial colony-forming units (CFU) per cornea were determined. Rabbits were immunized against alpha-toxin and subsequently challenged with S. aureus strain 8325-4 or Newman. All strains grew equivalently to approximately 7 log CFU/cornea at 25 h postinfection. SLE scores at 15, 20, and 25 h postinfection revealed that alpha-toxin - producing strains caused greater corneal pathology than strains deficient in alpha-toxin. A beta-toxin - deficient mutant produced significantly less ocular edema than its parent or rescued strains. The gamma-toxin-deficient mutant, relative to its parent strain or genetically rescued strain, had reduced virulence. These results demonstrate that the virulence of S. aureus involves mainly alpha-toxin and to a lesser extent gamma-toxin, with beta-toxin mediating minimal corneal pathology.
本研究的目的是确定α毒素、β毒素和γ毒素在金黄色葡萄球菌角膜炎兔模型中的致病作用。将金黄色葡萄球菌菌株8325-4、纽曼菌株及其同基因突变体基质内注射到兔角膜中。通过裂隙灯检查（SLE）对眼睛进行病理学评分，进行组织学检查，并确定每个角膜的细菌菌落形成单位（CFU）。用α毒素对兔子进行免疫，随后用金黄色葡萄球菌菌株8325-4或纽曼菌株进行攻击。在感染后25小时，所有菌株的生长情况相当，约为7 log CFU/角膜。感染后15、20和25小时的SLE评分显示，产生α毒素的菌株比缺乏α毒素的菌株引起更严重的角膜病变。β毒素缺陷突变体产生的眼部水肿明显少于其亲本或拯救菌株。相对于其亲本菌株或基因拯救菌株，γ毒素缺陷突变体的毒力降低。这些结果表明，金黄色葡萄球菌的毒力主要涉及α毒素，γ毒素的作用较小，β毒素介导的角膜病变最小。
