Long-Term Studies of Urease-Induced Crystallization in Human Urine

Abstract

Urine samples were inoculated with viable Proteus mirabilis or purified Jack bean urease. The subsequent pH increase and crystallization were followed for 2 weeks. Particle formation was detected much earlier and at a lower pH in urines inoculated with Proteus, in which a higher end pH was also reached. The crystal configuration in bacteria and urease inoculated samples was different. Crystal aggregation was also much more pronounced in the Proteus mirabilis inoculated samples. The total precipitation was markedly increased in the Proteus mirabilis inoculated samples. The presence of live Proteus mirabilis thus has a profound influence on urease-induced crystallization in human urine. Despite the formation of rather large crystal aggregates in the Proteus-inoculated urines, no firm aggregates of a "prestone" type were observed.

Homogeneous Precipitation of Calcium Carbonates by Enzyme Catalyzed Reaction

“…Furthermore, the role of this enzyme, generated by bacteria, in the formation of intracellular crystals of apatite, brushite, and struvite has been documented. These phosphate-containing minerals are involved in stone formation, caused by the urinary tract infections by such bacteria (19)(20)(21)(22). Since the decomposition of urea also causes an increases in the pH, the addition of urease was used to produce metal hydroxide particles, such as aluminum hydroxides (23,24) and aluminum basic sulfate (25).…”

Modelling crystal aggregation and deposition in the catheterised lower urinary tract

“…As the presence of a bacterial biofilm, increases the urinary pH, we could model this phenomenologically by relating the aggregation rates to the local pH. It is also possible that free bacteria within the urine could become trapped within the crystal clusters and further influence the aggregation (Edin-Liljegren et al 1994).…”

A Biomimetic Nano-Scale Aggregation Route for the Formation of Submicron-Size Colloidal Calcite Particles

“…It also appears that urease participates in systemic nitrogentransport pathways and possibly acts as a toxic defense protein (Mobley & Hausinger, 1989). Urease, generated by certain pathogenic bacteria, during urinary tract infections, plays a significant role in the formation of intracellular urinary stones (Edinliljegren et al, 1994). Recently, it was demonstrated that calcium carbonate polymorphs of different sizes and shapes can be obtained by homogeneous precipitation in solutions of calcium salts through the enzyme-catalyzed decomposition of urea by urease (Sondi & Matijević, 2001;Sondi & Salopek-Sondi, 2004).…”