Cowell B A, Willcox M D, Hobden J A, Schneider R P, Tout S, Hazlett L D
Cooperative Research Centre for Eye Research and Technology, The University of New South Wales, Sydney, Australia.
Exp Eye Res. 1998 Sep;67(3):347-56. doi: 10.1006/exer.1998.0524.
Pseudomonas aeruginosa is the most common pathogen among contact lens-associated infections. This study investigated the response of the murine cornea to infection with an ocular strain of P. aeruginosa isolated from a subject with an inflammatory adverse response to contact lens wear termed CLARE. Although this bacterium was isolated in confluency (greater than 2000 cfu lens-1) from the lens at the time of the inflammatory episode, no infection of the cornea subsequently developed. Male C57BL/6J mice (20 per strain) had their corneas scratched with a 26 gauge needle (3 parallel 1.0 mm wounds in the left eye only). The incisions were centered over the pupillary axis and penetrated the epithelial cell basal lamina and into the superficial stroma. The CLARE strain was found to persist (viable bacteria could be cultured from corneal homogenates) up to 8 hr, as did the virulent control strain ATCC 19660. At 24 hr, only ATCC 19660 could be cultured, indicating an inability of the strain isolated from CLARE, Paer1, to persist in the eye consistent with the human inflammatory episode. Histological examination of the mouse tissue showed further differences between infection by the two strains. Infection with ATCC 19660 resulted in tissue necrosis and a large population of polymorphonuclear leukocytes (PMNs) recruited to the wound site. In contrast, during infection with the CLARE strain, PMN recruitment was reduced and temporally delayed. The CLARE strain grew as well as ATCC 19660 in vitro but produced less protease activity, in particular less elastase. The decreased PMN response and decreased protease production by the CLARE strain may have been responsible for the lack of ocular damage and apparent healing of the wound. P. aeruginosa strains are considered to be invasive or cytotoxic to corneal tissue, however this strain may represent a third inflammatory type consistent with its differing pathology.
铜绿假单胞菌是隐形眼镜相关感染中最常见的病原体。本研究调查了小鼠角膜对从一名患有称为CLARE的隐形眼镜佩戴炎性不良反应的受试者分离出的眼部铜绿假单胞菌菌株感染的反应。尽管在炎症发作时从镜片中分离出该细菌时处于汇合状态（大于2000 cfu/镜片），但随后角膜并未发生感染。雄性C57BL/6J小鼠（每个品系20只）用26号针头划破角膜（仅左眼有3条平行的1.0毫米伤口）。切口位于瞳孔轴上方，穿透上皮细胞基底层并进入浅层基质。发现CLARE菌株可持续存在长达8小时（可从角膜匀浆中培养出活菌），强毒株对照菌株ATCC 19660也是如此。在24小时时，仅能培养出ATCC 19660，这表明从CLARE分离出的菌株Paer1无法在眼中持续存在，这与人类炎症发作情况一致。对小鼠组织的组织学检查显示两种菌株感染之间存在进一步差异。用ATCC 19660感染导致组织坏死，大量多形核白细胞（PMN）募集到伤口部位。相比之下，在CLARE菌株感染期间，PMN募集减少且时间延迟。CLARE菌株在体外生长情况与ATCC 19660相同，但产生的蛋白酶活性较低，尤其是弹性蛋白酶较少。CLARE菌株的PMN反应降低和蛋白酶产生减少可能是导致眼部无损伤且伤口明显愈合的原因。铜绿假单胞菌菌株被认为对角膜组织具有侵袭性或细胞毒性，然而该菌株可能代表一种与其不同病理相一致的第三种炎症类型。
