Aim. To study the effect of prophylactic immunization with combined Staphylococcus-Proteus-Pseudomonas vaccine in combination with the probiotic Bacillus subtilis on the development of recurrent nephrolithiasis in patients after percutaneous nephrolithotomy (PCNL).
Materials and methods. A total of 76 patients with a high infectious risk of stone formation in the early postoperative period after PCNL were included in the study. All patients received antibiotic therapy in accordance with the current guidelines as indicated. The patients were divided into 3 groups. In the comparison group (n=30), patients continued to receive antibiotics on the outpatient basis. In the group A (n=20), in addition to antibiotics, two-stage immunization with Staphylococcus-Proteus-Pseudomonas vaccine was performed. In the group B (n=26), additionally, patients received probiotic preparation "Bactisporin dry", which is a lyophilized spore-forming bacteria Bacillus subtilis strain 3N. All participants had urine culture and stone analysis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A study of specific antibodies level and factors of cellular and humoral immunity was carried out at specific time points. The duration of follow-up was 36 months.
Results. The study revealed a difference in the pathogens isolated from urine and infection stones in the same patient. This convincingly suggests that pathogens form biofilms in the stones and are not detected during routine urine culture. The main pathogens isolated from the stones were Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus epidermidis and Klebsiella pneumonia. Microbial associations were found in 25.7% of cases. The Staphylococcus-Proteus-Pseudomonas vaccine demonstrated good immunogenicity, its antigenic components provided protective properties against autologous and opportunistic bacteria. In addition to the ability to induce a specific response to antigens, the vaccine stimulated the phagocytic activity of neutrophils.
Immunization with the combined Staphylococcus-Proteus-Pseudomonas vaccine in combination with probiotic results in uncomplicated postoperative course in 84% of patients. Hospital-acquired infectious and inflammatory complications were seen in 16.2% of cases. The recurrence of stone formation in this group of patients within 36 months was 8.2%. In patients receiving only combined Staphylococcus-Proteus-Pseudomonas vaccine after PCNL, the postoperative period was uneventful in 65% of cases. The rate of upper urinary tract infection was 35%, while the inflammatory process was accompanied by mild clinical manifestations and quickly resolved. Recurrence of stone formation during the follow-up was seen in 18% of patients. In the control group, the proportion of uncomplicated cases in patients with nephrostomy tube was 40%, the development of pyelonephritis was noted in 60% of cases, and recurrent stones within 36 months were diagnosed in 46.7% of cases.
Conclusion. Our results emphasize that the role of an infectious factor in the development of recurrent nephrolithiasis after PCNL is often underestimated. The use of a specific vaccination and the Bacillus subtilis preparation in patients with a high infectious risk of recurrent stone formation allows to achieve a significant reduction in the recurrence rate (more than 5 times) compared to the control group during 36 months of postoperative follow-up.

Keywords: urolithiasis, recurrent kidney stones, percutaneous nephrolithotomy, antibiotic resistance, vaccination, probiotic therapy, Bacillus subtilis