CORNEAL VIRULENCE OF STAPHYLOCOCCUS-AUREUS - ROLES OF ALPHA-TOXIN AND PROTEIN-A IN PATHOGENESIS
CORNEAL VIRULENCE OF STAPHYLOCOCCUS-AUREUS - ROLES OF ALPHA-TOXIN AND PROTEIN-A IN PATHOGENESIS
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DOI：
10.1128/iai.62.6.2478-2482.1994
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发表时间：
1994-06-01
影响因子：
3.1
通讯作者：
OCALLAGHAN, RJ
中科院分区：
文献类型：
--
作者：
CALLEGAN, MC;ENGEL, LS;OCALLAGHAN, RJ
金黄色葡萄球菌产生多种蛋白质，包括α毒素和蛋白A，这可能导致角膜炎期间的角膜组织损伤。我们研究了角膜感染所产生的基质内注射四个S。金黄色葡萄球菌菌株--三种同基因突变体，一种缺乏α-毒素（Hly（-）Spa（+）），一种缺乏蛋白A（Hly（+）Spa（-）），一种既缺乏α-毒素又缺乏蛋白A（Hly（-）Spa（-）），以及野生型（Hly（+）Spa（+））--在实验性角膜炎的兔模型中。兔角膜层内注射100 CFU的四种菌株之一，并在25小时内通过裂隙灯生物显微镜检查眼睛。每隔5小时取角膜匀浆测定CFU和中性粒细胞髓过氧化物酶活性。所有菌株在感染后0 - 10 h具有相同的对数生长曲线，此后CFU保持恒定在10（7）CFU/角膜。在感染后15 h，Hly（+）菌株感染眼的裂隙灯检查评分显著高于Hly（-）感染眼。此时，在Hly（+）感染的眼睛中观察到明显的上皮糜烂，但在Hly（-）感染的眼睛中未观察到。在感染后20和25 h，Hly（+）感染角膜的髓过氧化物酶活性显著高于Hly（-）感染角膜。Spa（+）和pa（-）感染的眼睛在裂隙灯检查评分或髓过氧化物酶活性方面没有差异。这些结果表明，α-毒素，而不是蛋白A，是葡萄球菌性角膜炎的主要毒力因子，介导了这种细菌病原体感染的眼睛角膜组织的破坏。
Staphylococcus aureus produces a variety of proteins, including alpha-toxin and protein A, that could contribute to corneal tissue damage during keratitis. We examined corneal infections produced by intrastromal injection of four S. aureus strains-three isogenic mutants, one lacking alpha-toxin (Hly(-) Spa(+)), one lacking protein A (Hly(+) Spa(-)), and one lacking both alpha-toxin and protein A (Hly(-) Spa(-)), and the wild type (Hly(+) Spa(+))-in a rabbit model of experimental keratitis. Rabbit corneas were injected intrastromally with 100 CFU of one of the four strains, and the eyes were examined by slit lamp biomicroscopy over a 25-h period. Corneal homogenates were used for determination of CFU and neutrophil myeloperoxidase activity at 5-h intervals. All strains had the same logarithmic growth curve from 0 to 10 h postinfection, after which CFU remained constant at 10(7) CFU per cornea. By 15 h postinfection, slit lamp examination scores were significantly higher for eyes infected with Hly(+) strains than for Hly(-)-infected eyes. At this time, distinct epithelial erosions were seen in Hly(+)-infected eyes but not in Hly(-)-infected eyes. Myeloperoxidase activity was significantly greater for Hly(+)-infected corneas than for Hly(-)-infected corneas at bath 20 and 25 h postinfection. Spa(+)- and pa(-)-infected eyes showed no differences in slit lamp examination scores or myeloperoxidase activities. These results suggest that alpha-toxin, but not protein A, is a major virulence factor in staphylococcal keratitis, mediating the destruction of corneal tissue in eyes infected with this bacterial pathogen.