Crystallization of struvite from artificial urine in the presence of Proteus mirabilis microorganisms depends strongly on pH value. At small value of pH, struvite yields crystals of coffin-like habit with very specific structure. The analysis using scanning electron microscopy shows that the crystals possess well-defined faces, but higher magnifications show very specific structuration as if the crystals were built from small three-dimensional subunits. The possible role of microorganisms in the formation of such a structuration is analyzed. At higher pH value, the crystals exhibit dendritic growth with main trunk and branches. Although the formation mechanism of the specific structuration as well as dendritic structures is unknown, the nature of forces for such an alignment is analyzed. The revealed porous internal structure of struvite is also analyzed. The investigations provide evidence for the importance of biological regulation in crystallization process.

Interleukin‐8 (IL‐8) has been implicated in the pathogenesis of several human respiratory diseases, including tuberculosis (TB). Importantly and in direct relevance to the objectives of this report quite a few findings suggest that the presence of IL‐8 may be beneficial for the host. IL‐8 may aid with mounting an adequate response during infection with Mycobacterium tuberculosis (M. tb); however, the underlying mechanism remains largely unknown. The major goal of our study was to investigate the contribution of IL‐8 to the inflammatory processes that are typically elicited in patients with TB. We have shown for the first time that IL‐8 can directly bind to tubercle bacilli. We have also demonstrated that association of IL‐8 with M. tb molecules leads to the augmentation of the ability of leukocytes (neutrophils and macrophages) to phagocyte and kill these bacilli. In addition, we have shown that significant amount of IL‐8 present in the blood of TB patients associates with erythrocytes. Finally, we have noted that IL‐8 is the major chemokine responsible for recruiting T lymphocytes (CD3⁺, CD4⁺, and CD8⁺ T cells). In summary, our data suggest that the association of IL‐8 with M. tb molecules may modify and possibly enhance the innate immune response in patients with TB.

Formation of infectious urinary calculi is the most common complication accompanying urinary tract infections by members of the genusProteus. 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 [Ca₁₀(PO₄)₆.CO₃] and struvite (MgNH₄PO₄.6H₂O), respectively. This effect may also be enhanced by bacterial polysaccharides. Macromolecules of such kind contain negatively charged residues that are able to bind Ca²⁺and Mg²⁺, leading to the accumulation of these ions around bacterial cells and acceleration of the crystallization process. The levels of Ca²⁺and Mg²⁺ions bound by wholeProteuscells were measured, as well as the chemical nature of isolated LPS polysaccharides, and the intensity of thein vitrocrystallization process was compared in a synthetic urine. The results suggest that the sugar composition ofProteusLPS 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.

The natural microbiota of the urinary tract includes Lactobacillus spp., which secrete molecules with antimicrobial properties and have antagonistic activity against many pathogens. This paper focuses on the antibacterial effect of Lactobacillus strains isolated from urine against clinical strains of Proteus mirabilis isolated from kidney stones and from urine with coexisting urolithiasis. The study involved analyzing the main antimicrobial molecules secreted by Lactobacillus. In order to indicate which agent had the strongest antimicrobial effect, the supernatants were made alkaline and treated with catalase and high temperature. Both treated and untreated supernatants were analyzed for their activity. Exposing uropathogens to all untreated cell-free supernatants of Lactobacillus significantly reduced their growth, and it was established that these properties were related to organic acid secretion by these strains. Using LC–MS/MS and spectrophotometric techniques, lactic, citric, and succinic acids were determined qualitatively and quantitatively. The influence of these acids on the P. mirabilis growth and biofilm formation and their influence on membrane permeability were also investigated. The results indicate that organic acids secreted by Lactobacillus strains have a high antibacterial potential and could be used as novel agents in the treatment of urinary tract infections caused by P. mirabilis.