The carried out study revealed etiological features of pyelonephritis in children with simultaneous establishing of biofilms formation peculiarities by causative agents of pyelonephritis in children with the definition of stages for each of the isolates and establishing the ability to produce planktonic cells by daily biofilms as a factor of microorganisms colonization for diagnostic criteria development and further establishing of effective antimicrobial means to prevent pyelonephritis recurrence in children.
It was first established at the regional level that the main causative agents of primary acute and chronic pyelonephritis in children were Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus spp .; the causative agents of secondary pyelonephritis in children with congenital hydronephrosis - Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus epidermidis, Pseudomonas aeruginosa, Candida albicans, Proteus spp.
Scientific research on determining the stages of biofilm formation has been further developed. The following five stages were added to the classic five stages of biofilm formation: 6 - dissemination of planktonic cells formed inside the primary biofilm and as a result of dispersion, 7 - reabsorption of planktonic cells on substrates, 8 - reagregation, 9 - segmentation of bacterial secondary biofilm.
For the first time, the peculiarities of biofilm formation in children with pyelonephritis depending on the clinical form of the disease and age category were revealed. It was found that in children with acute pyelonephritis the formation of biofilm by isolates is slower than in children with chronic form and pyelonephritis on the background of hydronephrosis. In children with chronic pyelonephritis and pyelonephritis on the background of congenital hydronephrosis of older age, high-density biofilms are formed, which produce a large number of planktonic cells, which spread throughout the body and form dense secondary biofilms, which leads to frequent recurrences.
Scientific provisions for the improvement of methods of antimicrobial therapy of pyelonephritis with the use of derived from nitrofurans in children were further developed in order to prevent complications by determining the method of inhibiting the formation of biofilms of microorganisms, pathogens of pyelonephritis. It was found for the first time that derived from nitrofurans in a therapeutic dose inhibit the production of planktonic cells of microorganisms by exposure to primary biofilms in both acute and chronic pyelonephritis in children, which prevents the formation of secondary biofilms due to the formation of "pores - slits" through which that prevents the development of relapses.
It was found that they changed in children of different ages: subpopulations of lymphocytes indices with CD3+, CD4+, CD8+, CD25+ and CD95+ markers of differentiation were reduced in young children and misbalance in cellular immunity link in middle-aged and older children were marked: a reliable increase of CD95+ with a simultaneous decrease of CD3+, CD4+, CD8+, CD25+. It is established that the disbalance of cellular and humoral parts of immunity in children with primary and secondary pyelonephritis contributes to the recurrence of the pathological process, its progression and deterioration of the further course of pyelonephritis.
For the first time it was found that in older children with chronic pyelonephritis, with increasing density of biofilms significantly increases the content of antigens in NETs, ie the ability of neutrophils to capture more pathogens at the time of death.
It was first established that the intensity of phagocytosis and the ability to form NETs with the highest content of antigens is characteristic of children with chronic pyelonephritis caused by Enterococcus faecalis and children with secondary pyelonephritis in the active stage of the disease of the older group.
Scientific data on leukocyte apoptosis in pyelonephritis in children have been supplemented: the highest activity of leukocyte apoptosis in primary pyelonephritis in children aged 0–3 years with acute form at an early stage has been revealed, at the same time it has been established that in children with chronic pyelonephritis including neutrophils, in the early stage of apoptosis is significantly increased, due to the polyetiology of the disease and the occurrence of complications.
It is proved that the loss of lymphocytes due to apoptosis is a component of physiological changes in nonspecific immunity that occurs in pyelonephritis in middle-aged and older children, especially against the background of congenital hydronephrosis.
