Introduction. A new paradigm in the diagnosis, treatment, and prevention of urinary tract infections (UTIs) is currently emerging in medical science, based on the understanding that urine is not sterile and the urinary tract is inhabited by a diverse microbiome. Recurrent UTIs remain one of the leadingproblems in the management of patients with neurogenic lower urinary tract dysfunction (NLUTD), but the dependence of UTI recurrence rate on the composition of the urinary microbiome has not been studied.

The purpose of the study was to assess the changes in the urinary microbiome in patients with neurogenic bladder and the relationship between these changes and the frequency of recurrent urinary tract infections.

Materials and methods. The urinary microbiome was studied in 118 patients with neurogenic bladder without UTI recurrence and 15 healthy volunteers as a control group. Urine cultures were performed using the modified enhanced quantitative urine culture (EQUC) method, with determination of antimicrobial susceptibility of the microorganisms, and real-time PCR analysis of urine samples using the Androflor kit (DNA-Technology, Russia).

Results. Bacterial growth was obtained in 72% of urine cultures from NLUTD patients and 80% in the control group. A total of 175 isolates were obtained: from 1 to 6 (on average 1.76±1.22) per patient. PCR analysis of urine samples revealed the presence of microbial DNA in all urine samples, including those that did not show growth on culture media. The most common microorganisms in the microbiome of NLUTD patients were: Escherichia coli (20%), Enterococcus faecalis (19%), Staphylococcus spp. (15%), Streptococcus spp. (12%), and Klebsiella pneumoniae (9%). The microbiome of patients with preserved spontaneous urination was closest to the control group, but differed in an increased proportion of Enterobacteriaceae and Enterococcus spp. The presence of a significant number of representatives of the normal microflora, such as Lactobacillus spp., Streptococcus spp., Staphylococcus spp., and a more diverse composition in general, distinguished the urinary microbiome of patients using intermittent catheterization from those with a permanent drainage. Urine cultures of patients with recurrent UTIs yielded fewer isolates than those without frequent infection exacerbations (1±0.58 and 2.25±1.29, respectively, p=0.001).

Conclusions. The urinary microbiome of NLUTD patients is dominated by Enterobacteriaceae. The presence of a significant number of representatives of the normal microflora, such as Lactobacillus spp., Streptococcus spp., Staphylococcus spp., and a more diverse composition in general, distinguish the urinary microbiome of patients with intermittent catheterization from those with cystostomy or a permanent urethral catheter. Species diversity of the microbiome is associated with a lower frequency of recurrent urinary tract infections.