Proteus mirabilis is a common cause of infectious urolithiasis. The first stage in the formation of urinary stones is the crystallization of mineral salts in the urine induced by urease activity of this microorganism. Lactobacillus spp. are an important component of the human microbiota and in large quantities occur in foods. Regardless of their origin, those with probiotic properties are proposed as an alternative to antibiotic therapy in the treatment of urinary tract infections. The aim of the study was to check the effect of selected Lactobacillus plantarum and Lactobacillus brevis strains on crystallization caused by P. mirabilis in an in vitro experiment. It has been confirmed that selected Lactobacillus strains have antibacterial properties and colonize the urinary tract epithelium. During 24-h incubation of bacterial cultures, containing P. mirabilis and individual Lactobacillus strains, in synthetic urine, bacterial viability (CFU/mL), pH, and crystallization were determined. Crystallization was assessed quantitatively and qualitatively using AAS and XRD techniques as well as phase-contrast microscopy. It has been shown that in the presence of selected Lactobacillus strains, the culture pH increases faster, especially after 8 h of incubation, compared with the pure P. mirabilis culture. An increase in pH reduces the viability of P. mirabilis; however, in the presence of some lactobacilli, the uropathogen grows more intensively. The presence of Lactobacillus also affected crystallization by increasing its intensity, and the resulting crystals were larger in size. Tested L. plantarum and L. brevis strains could therefore accelerate the formation of urinary stones and development of infection.

奇异变形杆菌是感染性尿石症的常见原因。尿路结石形成的第一阶段是由该微生物的脲酶活性引起的尿液中矿物盐的结晶。乳酸菌属。是人体微生物群的重要组成部分，大量存在于食物中。不管它们的来源如何，那些具有益生菌特性的产品都被提议作为治疗尿路感染的抗生素疗法的替代品。该研究的目的是检查选定的植物乳杆菌和短乳杆菌菌株对奇异假单胞菌引起的结晶的影响在体外实验中。经证实，选定的乳杆菌菌株具有抗菌特性并定植于泌尿道上皮细胞。在 24 小时培养合成尿中含有奇异变形杆菌和单个乳杆菌菌株的细菌培养物期间，测定了细菌活力 (CFU/mL)、pH 值和结晶。使用 AAS 和 XRD 技术以及相衬显微镜对结晶进行了定量和定性评估。已经表明，与纯的奇异变形杆菌相比，在选定的乳酸杆菌菌株存在下，培养物的 pH 值升高得更快，尤其是在孵育 8 小时后文化。pH 值的增加会降低奇异假单胞菌的生存力；然而，在一些乳酸杆菌存在的情况下，尿路病原体会更加密集地生长。乳杆菌的存在也通过增加其强度影响结晶，并且所得晶体尺寸更大。因此，经过测试的植物乳杆菌和短乳杆菌菌株可以加速泌尿系结石的形成和感染的发展。