Jones B D, Mobley H L
Infect Immun. 1987 Sep;55(9):2198-203. doi: 10.1128/iai.55.9.2198-2203.1987.
Bacterial urease, particularly from Proteus mirabilis, has been implicated as a contributing factor in the formation of urinary and kidney stones, obstruction of urinary catheters, and pyelonephritis. Weekly urine specimens (n = 1,135) from 32 patients, residing at two chronic-care facilities, with urinary catheters in place for greater than or equal to 30 days yielded 5,088 phenotypically and serotypically diverse bacterial isolates at greater than or equal to 10(5) CFU/ml. A total of 86% of specimens contained at least one urease-positive species, and 46% of 3,939 gram-negative bacilli were urease positive. For investigation of genetic relatedness of urease determinants, whole-cell DNA from 50 urease-positive isolates each of Providencia stuartii, Providencia rettgeri, P. mirabilis, Proteus vulgaris, and Morganella morganii were hybridized with a urease gene probe derived from within the urease operon of Providencia stuartii BE2467. The percentage of strains hybridizing with the gene probe was 98 for Providencia stuartii, 100 for Providencia rettgeri, 70 for P. mirabilis, 2 for M. morganii, and 0 for P. vulgaris. Electrophoretic mobilities of ureases from representative isolates revealed nine different patterns among the five species. The urease gene probe hybridized with fragments of HindIII-digested chromosomal DNA from all isolates except M. morganii. Fragment sizes differed between species. Molecular sizes of the enzymes, determined by Sephacryl S-300 chromatography, were found to be 280 kilodaltons (kDa) (P. mirabilis), 323 to 337 kDa (Providencia stuartii, Providencia rettgeri, P. mirabilis, P. vulgaris), 620 kDa (providencia rettgeri), and greater than 700 kDa (M. morganii, Providencia rettgeri). Kms ranged from 0.7 mM urea for M. morganii to 60 mM urea for a P. mirabilis isolate. In general, P. mirabilis ureases demonstrated lower affinities for substrate but hydrolyzed urea at rates 6- to 25-fold faster than did enzymes from other species, which may explain the frequent association of this species with stone formation.
细菌脲酶，尤其是奇异变形杆菌产生的脲酶，被认为是导致尿路结石和肾结石形成、导尿管阻塞以及肾盂肾炎的一个因素。对居住在两家慢性病护理机构、导尿管留置时间大于或等于30天的32名患者的每周尿液样本（n = 1135份）进行检测，共获得5088株表型和血清型各异的细菌分离株，其浓度大于或等于10⁵CFU/ml。总共86%的样本至少含有一种脲酶阳性菌，在3939株革兰氏阴性杆菌中，46%为脲酶阳性。为了研究脲酶决定簇的遗传相关性，分别从斯氏普罗威登斯菌、雷氏普罗威登斯菌、奇异变形杆菌、普通变形杆菌和摩根摩根菌中选取50株脲酶阳性分离株，提取其全细胞DNA，与源自斯氏普罗威登斯菌BE2467脲酶操纵子内部的脲酶基因探针进行杂交。与基因探针杂交的菌株比例分别为：斯氏普罗威登斯菌98%、雷氏普罗威登斯菌100%、奇异变形杆菌70%、摩根摩根菌2%、普通变形杆菌0%。对代表性分离株的脲酶进行电泳迁移率分析，结果显示这五个菌种之间有九种不同的模式。脲酶基因探针与除摩根摩根菌外的所有分离株经HindIII酶切的染色体DNA片段杂交。不同菌种的片段大小有所不同。通过Sephacryl S - 300层析法测定的酶分子大小分别为：奇异变形杆菌280千道尔顿（kDa）、斯氏普罗威登斯菌、雷氏普罗威登斯菌、奇异变形杆菌、普通变形杆菌323至337 kDa、雷氏普罗威登斯菌620 kDa、摩根摩根菌和雷氏普罗威登斯菌大于700 kDa。米氏常数（Km）范围从摩根摩根菌的0.7 mM尿素到一株奇异变形杆菌分离株的60 mM尿素。总体而言，奇异变形杆菌脲酶对底物的亲和力较低，但水解尿素的速度比其他菌种的酶快6至25倍，这可能解释了该菌种与结石形成的频繁关联。
