Hunts J H, Matoba A Y, Osato M S, Font R L
Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.
Arch Ophthalmol. 1993 Apr;111(4):528-30. doi: 10.1001/archopht.1993.01090040120044.
Infectious crystalline keratopathy is a unique pauci-inflammatory infection of the cornea most commonly due to viridans type streptococci. We investigated the hypothesis that production of exopolysaccharide by streptococci, a property that can be induced by growth conditions, may contribute to the pathogenesis of infectious crystalline keratopathy by suppressing the ocular immune response.
Streptococcus sanguis type II was grown under two conditions, conventionally in brain-heart infusion broth and in 5% sucrose-supplemented brain-heart infusion broth, to promote exopolysaccharide formation. Rabbit corneas were inoculated by passage of 9-0 silk sutures soaked in bacterial suspensions.
Arborizing, sharply demarcated pauci-inflammatory lesions were noted in 71% of rabbit corneas inoculated with S sanguis type II grown in sucrose-supplemented media and in 25% of control corneas (P = .05). Suppurative lesions developed in the remaining corneas. Histologic evaluation of infectious crystalline keratopathy lesions revealed characteristic features.
Increased exopolysaccharide formation by S sanguis type II is associated with production of infectious corneal lesions that resemble those of infectious crystalline keratopathy.
感染性结晶性角膜病变是一种独特的角膜轻度炎症性感染，最常见的病因是草绿色链球菌。我们研究了一种假说，即链球菌产生胞外多糖（这种特性可由生长条件诱导）可能通过抑制眼部免疫反应而导致感染性结晶性角膜病变的发病机制。
II型血链球菌在两种条件下培养，一种是常规在脑心浸液肉汤中培养，另一种是在添加5%蔗糖的脑心浸液肉汤中培养，以促进胞外多糖的形成。通过浸泡在细菌悬液中的9-0丝线穿过兔角膜进行接种。
在接种了在添加蔗糖培养基中生长的II型血链球菌的兔角膜中，71%出现了树枝状、边界清晰的轻度炎症病变，而对照角膜中这一比例为25%（P = .05）。其余角膜出现化脓性病变。对感染性结晶性角膜病变的组织学评估揭示了其特征性表现。
II型血链球菌胞外多糖形成增加与产生类似于感染性结晶性角膜病变的感染性角膜病变有关。
