The role of nitric oxide synthase and cystatin C in the mechanisms of antimicrobial protection in children with urinary tract infections considering the etiological factor

Abstract

The aim of the study was to investigate the main etiological factors of urinary tract infections in children, the role of nitric oxide synthase and cystatin C in the mechanisms of antimicrobial protection in children with acute and chronic urinary tract infections. Materials and methods. The study groups consisted of 84 children (mean age – 10.0 ± 1.3 years). The main group was divided into subgroups: the first subgroup – 17 children with acute pyelonephritis, the second subgroup – 21 patients with chronic pyelonephritis, the third subgroup – 16 patients with acute cystitis, the fourth subgroup – 10 patients with unspecified urinary tract infections. The control group consisted of 20 relatively healthy children. The levels of inducible NO-synthase (NOS2) and cystatin C were measured by enzyme-linked immunosorbent assay. The etiological pathogen was identified in the urine of 200 patients with urinary tract infections. Results. Escherichia coli was identified as the dominant pathogen in 46.7 % of cystitis patients and in 66.6 % of chronic pyelonephritis patients. The next most frequently detected etiological agent in children with acute (27.3 % of cases) and chronic (25.6 %) pyelonephritis and unspecified urinary tract infection (32.2 %) was Enterococcus faecium. Proteus mirabilis was found in 26.6 % of patients with cystitis. The level of NOS2 in all the studied subgroups was significantly higher than that in the control group (P < 0.01). A statistically significant increase in the level of cystatin C in the main group (P < 0.05) was determined. The cystatin C-to-NOS2 ratios in the studied subgroups were 1.5–2.0 times lower than those in the control group (P < 0.05). Conclusions. The change in the spectrum of pathogens has been determined, which was a premise of the need for constant bacteriological monitoring. The development of the primary inflammatory process in the urinary tract occurred amidst a certain dysfunction of the immune system, which was manifested in an insufficient quantitative response of cystatin C, as well as high serum levels of inducible NO-synthase in the patients.