Lomholt J A, Poulsen K, Kilian M
Department of Medical Microbiology and Immunology, University of Aarhus, DK-8000 Aarhus C, Denmark.
Infect Immun. 2001 Oct;69(10):6284-95. doi: 10.1128/IAI.69.10.6284-6295.2001.
The genetic structure of a population of Pseudomonas aeruginosa, isolated from patients with keratitis, endophthalmitis, and contact lens-associated red eye, contact lens storage cases, urine, ear, blood, lungs, wounds, feces, and the environment was determined by multilocus enzyme electrophoresis. The presence and characteristics of virulence factors were determined by restriction fragment length polymorphism analysis with DNA probes for lasA, lasB, aprA, exoS, exoT, exoU, and ctx and by zymography of staphylolysin, elastase, and alkaline protease. These analyses revealed an epidemic population structure of P. aeruginosa, characterized by frequent recombination in which a particular successful clone may increase, predominate for a time, and then disappear as a result of recombination. Epidemic clones were found among isolates from patients with keratitis. They were characterized by high activity of a hitherto-unrecognized size variant of elastase, high alkaline protease activity, and possession of the exoU gene encoding the cytotoxic exoenzyme U. These virulence determinants are not exclusive traits in strains causing keratitis, as strains with other properties may cause keratitis in the presence of predisposing conditions. There were no uniform patterns of characteristics of isolates from other types of infection; however, all strains from urinary tract infections possessed the exoS gene, all strains from environment and feces and the major part of keratitis and wound isolates exhibited high elastase and alkaline protease activity, and all strains from feces showed high staphylolysin activity, indicating that these virulence factors may be important in the pathogenesis of these infectious diseases.
通过多位点酶电泳确定了从患有角膜炎、眼内炎、与隐形眼镜相关的红眼病患者、隐形眼镜储存盒、尿液、耳朵、血液、肺部、伤口、粪便以及环境中分离出的铜绿假单胞菌群体的遗传结构。通过使用针对lasA、lasB、aprA、exoS、exoT、exoU和ctx的DNA探针进行限制性片段长度多态性分析以及葡萄球菌溶血素、弹性蛋白酶和碱性蛋白酶的酶谱分析，确定了毒力因子的存在和特征。这些分析揭示了铜绿假单胞菌的流行群体结构，其特征是频繁重组，其中某个特定的成功克隆可能会增加，在一段时间内占主导地位，然后由于重组而消失。在角膜炎患者的分离株中发现了流行克隆。它们的特征是一种迄今未被识别的弹性蛋白酶大小变体具有高活性、碱性蛋白酶活性高以及拥有编码细胞毒性外酶U的exoU基因。这些毒力决定因素并非引起角膜炎的菌株所特有，因为具有其他特性的菌株在存在易感条件时也可能引起角膜炎。来自其他类型感染的分离株没有统一的特征模式；然而，所有来自尿路感染的菌株都拥有exoS基因，所有来自环境和粪便以及大部分角膜炎和伤口分离株都表现出高弹性蛋白酶和碱性蛋白酶活性，并且所有来自粪便的菌株都表现出高葡萄球菌溶血素活性，这表明这些毒力因子可能在这些传染病的发病机制中起重要作用。
