The paper is devoted to the investigation of antimicrobial activity of polymer nanocomposites of both low-density polyethylene and nonwoven polymeric material (a mixture of woven and polyester fibers) that had been impregnated by Cu nanoparticles. The microorganisms were grown according to generally accepted microbiological rules and on media recommended for each bacteria family. Formation of biofilms of microorganisms was studied on the surface of microtiter plates for enzyme-linked immunosorbent assay. After incubation of microtiter plates, the culture medium was removed from the wells. The wells were rinsed five times with sterile distilled water. The plates were air dried for 45 minutes and each well was stained with 1% crystal violet solution in water for 45 min. After staining, the plates were washed with sterile distilled water five times. The quantitative analysis of biofilm production was done by adding 95% ethanol for discoloration of the wells. The research shows the antibacterial activity of Cu nanoparticles on planktonic forms of the investigated microorganisms, which prevented the formation of dense biofilms. With the use of low-density polyethylene impregnated by Cu the ability to form biofilms by planktonic cells of the referent strains of microorganisms was detected to decrease by 1.7 (Escherichia coli), 12.3 (Klebsiella pneumonia) times in the studied strains and with the use of nonwoven polymeric material treated by Cu nanoparticles, the ability to form biofilms decreased by 1.8 (Escherichia coli) – 21.8 (Klebsiella pneumonia) times in the studied strains. In subjecting the formed daily biofilms of referent strains of microorganisms to Cu nanoparticles, the destruction of biofilms of the studied strains of microorganism was observed as well as violation of the integrity of the biofilm monolayer and decrease of density index in comparison with control values. As a result, the obtained polymer nanocomposites can be recommended for preventive use in the fight against nosocomial infections. The practical relevance of this study lies in the possibility of reducing the incidence of purulent-inflammatory diseases and mycoses and, accordingly, reduction of the costs of treating these diseases.

Харківський національний медичний університет,Кафедра мікробіології, вірусології та імунології ім. проф. Д.П. Гриньова

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.

Community-acquired pneumonia (CAP) in children is still one of the leading causes of morbidity and mortality, especially in developing countries. The World Health Organization (WHO) has reported that pneumonia accounts for 15% of all deaths of children under 5 years old. The aim of the present study was to find out the predominance of microorganisms in the respiratory tract in children. 334 strains of microorganisms were isolated: Gram-positive – 293 strains, Gram-negative – 41. From the pharynx 183 strains were isolated, from the nose – 94, from sputum – 57. Among Gram-positive microorganisms the following were isolated: Staphylococcus aureus 44 strains of microorganisms, S. epidermidis – 75, Group A β-hemolytic streptococci – 39, viridans streptococci – 55, Streptococcus pneumoniae – 34, Enterococcus faecalis – 2, Candida spp. – 38, Corynebacterium pseudodiphthericum – 6. Among Gram-negative microorganisms the following were isolated: Escherichia coli 4 strains of microorganisms, Klebsiella pneumoniae – 13, Pseudomonas aeruginosa – 6, Haemophilus influenzae – 11, Enterobacter cloacae – 7. Children were divided by age and diagnosis into four groups: I group – children with acute bronchitis (0–5 years of age), II group – children with acute bronchitis (5–18 years of age), III group – children with CAP (0–5 years of age), IV group – children with CAP (5–18 years of age). Materials used in the research – nasal swabs, throat swabs and sputum. Microorganisms were isolated and identified using standard microbiological methods. S. aureus was the predominant microorganism isolate from the pharynx in children with bronchitis (0–5 years). Group A β-hemolytic streptococci were isolated most often from the pharynx in children with bronchitis older than 5 years and in children with CAP less than 5 years of age. S. pneumoniae was most often isolated from the pharynx in children older than 5 years of age with CAP. S. aureus was the main microorganism, isolated from the nose in children with bronchitis in all age groups; in patients with CAP it was the predominant microorganism in children older than 5 years of age. S. aureus was the predominant microorganism, isolated from sputum in children with bronchitis older than 5 years. S. pneumoniae was the predominant microorganism, isolated from sputum in children with CAP older than 5 years. The research showed that S. pneumoniae is still one of the main pathogens that cause CAP in school aged children.