Crystallization of urine mineral components may depend on the chemical nature of Proteus endotoxin polysaccharides

Abstract

Formation of infectious urinary calculi is the most common complication accompanying urinary tract infections by members of the genus Proteus. The major factor involved in stone formation is the urease produced by these bacteria, which causes local supersaturation and crystallization of magnesium and calcium phosphates as carbonate apatite [Ca 10 (PO 4 ) 6 .CO 3 ] and struvite (MgNH 4 PO 4 .6H 2 O), respectively. This effect may also be enhanced by bacterial polysaccharides. Macromolecules of such kind contain negatively charged residues that are able to bind Ca 2þ and Mg 2þ , leading to the accumulation of these ions around bacterial cells and acceleration of the crystallization process. The levels of Ca 2þ and Mg 2þ ions bound by whole Proteus cells were measured, as well as the chemical nature of isolated LPS polysaccharides, and the intensity of the in vitro crystallization process was compared in a synthetic urine. The results suggest that the sugar composition of Proteus LPS may either enhance or inhibit the crystallization of struvite and apatite, depending on its chemical structure and ability to bind cations. This points to the increased importance of endotoxin in urinary tract infections.

Proteus sp. – an opportunistic bacterial pathogen – classification, swarming growth, clinical significance and virulence factors

“…It was found that struvite exhibits polar properties , ROMANOWSKI et al 2010. TORZEWSKA et al (2003) confirmed this observations and showed that urinary stone formation due to the urease activity, may be modified by surface O-antigens being a part of lipopolysaccharides (LPS). The sugar composition of these polysaccharides may either enhance or inhibit the crystallization of struvite and carbone apatite depending on their chemical structure and ability to bind cations.…”

Complicated Catheter-Associated Urinary Tract Infections Due toEscherichia coliandProteus mirabilis

“…Additionally, this barrier plays a role in late biofilm development (346) and protects against desiccation and phage attack. It also assists in accelerating the urinary stone crystallization process via electrostatic interactions that accumulate urinary ions at the bacterial surface (55,87,408). During the course of UTIs, antibodies that recognize antigenic components of uropathogens are produced.…”

“…Due to the acidic, negatively charged residues on its surface, a possible function of LPS during UTIs and CAUTIs is its ability to attach and bind cations such as Ca 2ϩ and Mg 2ϩ , leading to the accumulation of these ions around bacterial cells and the acceleration of the crystallization process (408). Studies by Torzewska et al (408) indicated that the level of Ca 2ϩ and Mg 2ϩ cation binding on the surface of Proteus organisms is dependent upon the sugar composition of the Proteus LPS as determined by in vitro crystallization in artificial urine.…”

Molecular and Genetic Analyses of the Putative Proteus O Antigen Gene Locus

“…Both LPSs and CPSs have been considered to play an important role in the progression of UTIs, in addition to affecting both kidney and bladder stone formation (7,25,35). Furthermore, the LPS O antigen confers protection against serum-mediated bactericidal activity (13,27), and bacterial LPS released from bacteria is a biologically active endotoxin that causes a broad spectrum of pathophysiological conditions, including septic shock (26).…”