The aim: to study the stages of primary and secondary biofilms formation by the leading pathogens in children with pyelonephritis on congenital hydronephrosis background depending on child’s age. Materials and methods. Venflons, catheters, urine were used as material for microbiological study. Identification of microorganisms was provided with MICRO-LA-TESTÒID kits. Isolates were tested for ability to form biofilms in Petri dishes with d=40 mm. The morphological structure of the biofilms was studied by scanning electron microscopy. Results: The study of structural and functional features of biofilms formation by leading pathogens of in children with pyelonephritis on congenital hydronephrosis background depending on child’s age revealed a number of features and patterns. In addition to the classical stages of biofilms formation as 3D structure there was found a dissemination of planktonic cells with the release of bacteria or loss of single fragments that spread throughout the body and attach to the substrate with the formation of a new or secondary biofilm. In children under 3 years it was shown that the cocci attachment to the substrate appeared faster than in gram-negative rods and had appearance of separate structures. The longest stage of primary biofilms formation in young children was the co-aggregation. Detecting an ability to colonize with the formation of a secondary biofilm in isolates established that the longest stage was re-adsorption and the shortest was re-aggregation, which lasted 2 hours in all detected pathogens. In middle-aged children, the duration of adhesion stage was reduced by 1-2 hours compared with it in young children. Conclusions. Scientific data about the stages of biofilms formation by microorganisms, causative agents of pyelonephritis in children was updated. Adhesion stage of isolates from elder children with pyelonephritis on background of congenital hydronephrosis underwent faster in the formation of secondary biofilms than in primary, and it formed the possibility for chronic process and the development of recurrences. The duration of each stage in biofilms formation by causative agents of pyelonephritis in children with congenital hydronephrosis depended on the age of the child and the properties of microorganisms

Action of antibiotics to the microorganisms in their biofilm forms was detected. Strains of Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa were used in the research. Microorganisms were isoloated from children with community-acquired pneumonia. Ability of microorganisms to form biofilms was detected in 96-well plates. For detection action of antibacterial drugs to the biofilm forms of isolated microorganisms Ceftriaxon, Amikacin, Clarithromycin and Levofloxacin were chosen. Serial dilution method was used to determine susceptibility of microorganisms to the action of antibacterial drugs. All strains, which were isolated from patients with community acquired pneumonia, were able to form biofilms. Comparing optical density (OD) of S. aureus, S. pneumoniae and P. aeruginosa after action of antibiotics to the primary biofilms and OD of primary biofilms without action of antibacterial drugs revealed that in specific dilutions depth of primary biofilms with antibiotic action was thinner than depth of primary biofilms without action of antibacterial drugs. Comparing OD of S. aureus, S. pneumoniae and P. aeruginosa after action of antibiotics to the secondary biofilms and OD of secondary biofilms without action of antibacterial drugs revealed that in certain dilutions depth of secondary biofilms with antibiotic action was thicker than depth of secondary biofilms without action of antibacterial drugs. Keywords: biofilms, antibiotics, community acquired pneumonia, children.

Determination of the effect of Ag nanoparticles impregnated in medical polyethylene products together with the LED radiation of the red and violet spectra on the ability of microorganisms to form biofilms and on daily biofilms.

The purpose of the study was to detect ability to form biofilms by microorganisms that cause respiratory tract infections. Materials and methods. The study involved 97 strains of microorganisms. Microorganisms were isolated from children with respiratory tract infections. All strains, isolated from patients, were able to form biofilms. There were 44 strains of S. aureus (from patients with pneumonia – 13 strains, from patients with other respiratory diseases – 31), 34 strains of S. pneumoniae (pneumonia – 27 strains, other respiratory diseases – 7), 13 strains of K. pneumoniae (pneumonia – 6 strains, other respiratory diseases – 7), 6 strains of P. aeruginosa (pneumonia – 5 strains, other respiratory diseases – 1). Children were treated at the pulmonary department and intensive care unit in Kharkiv Regional Children's Clinical Hospital. Results and discussion. The optical density of primary biofilms formed by Gram-positive microorganisms was 1.33±0.24 Units of OD, and their secondary biofilms was 0.32±0.10 Units of OD. In patients with pneumonia optical density of primary biofilms of Gram-positive microorganisms was 1.48±0.21 Units of OD and of secondary biofilms was 0.30±0.08 Units of OD. Optical density of primary biofilms of Gram-positive microorganisms in patients with other respiratory infections was 1.18±0.15 Units of OD, of secondary biofilms was 0.35±0.12 Units of OD. The optical density of primary biofilms formed by Gram-negative microorganisms was 2.01±1.03 Units of OD, optical density of secondary biofilms was 1.06±0.42 Units of OD. In patients with pneumonia optical density of primary biofilms of Gram-negative microorganisms was 2.57±0.87 Units of OD, of secondary biofilms was 1.21±0.50 Units of OD. Optical density of primary biofilms of Gram-negative microorganisms in patients with other respiratory infections was 1.24±0.66 Units of OD, of secondary biofilms was 0.84±0.11 Units of OD. Conclusion. Gram-negative microorganisms in general formed more massive biofilms compared with Gram-positive microorganisms. Among all microorganisms P. aeruginosa formed the thickest primary and secondary biofilms. Strains of P. aeruginosa isolated from patients with pneumonia formed the thickest primary and secondary biofilms. Strains of S. aureus isolated from patients with other respiratory infections formed most massive primary biofilms, strains of K. pneumoniae formed the hardest secondary biofilms in this group

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