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The characteristics of resistome and virulome structure of four carbapenem-resistant Klebsiella pneumoniae clinical strains are present in the work. Two strains belonged to the sequence-type ST395, one strain - ST2262, one strain - to the new sequence-type 5816. The genes of fimbriae, enterobactin, beta-lactamase SHV type, resistance to fosfomycin fosA and transport of fluoroquinolones oqxAB in all Klebsiella strains chromosome structure were identified. The determinants of yersineobactin and aerobactin are enriched the virulome of ST395 NNKP315 and NNKP343 strains. The aerobactin genes are located on IncHI1B plasmids (IncHI1B/FIB) which highly homologous to the virulence pLVPK and pK2044 plasmids. IncR, IncL, IncQ plasmids carrying blaOXA-48, blaCTX-M-15, blaOXA-1, blaTEM-1, qnrS1, tetA, sul1, dfrA1, aac(6 ‘)-Ib-cr, catA1, catB3 etc. were identified in these strains. As a result of in silico analysis, an assumption about the localization of the blaOXA-48 in the structure of the IncHI1B plasmid of NNKP315 strain was made. This plasmid also contains the aminoglycosidases genes inserted into a class 1 integron In822. The mutations were found in the porin proteins OmpK35, OmpK36 and OmpK37 genes, which increases the carbapenem resistance. The virulome of NNKP16 (ST2262) strain additionally includes of the iron utilization system kfuABC chromosomal genes, and the virulome of NNKP15 (ST5816) strain contains of the capsular polysaccharide kvgAS and microcin E492 genes. Additional determinants of resistance were not identified in the resistome structure of K. pneumoniae NNKP16 and only the blaCTX-M-15 gene was found in the NNKP15 strain. The absence of acquired resistance genes seems to be due to the presence of the type I-E CRISPR-Cas system. Multiple drug resistance of the studied strains is associated with mutations identified in the gene structure of porin proteins OmpK36 and OmpK37, as well as the activity of efflux systems. It was showed the stop codon formation in the nucleotide sequence of the regulatory gene ramR to both strains, which can potentially provide overexpression of AcrAB efflux proteins.

Objective. To study in vitro antimicrobial resistance and prevalence of the most clinically important carbapenemases genes in Klebsiella pneumoniae clinical isolates in Nizhny Novgorod. Materials and Methods. A total of 238 K. pneumoniae clinical isolates from upper and lower respiratory tracts, abdominal cavity, urogenital tract, and wound discharge were tested in this study. Species identification was done using WalkAway 96 analyzer (Siemens, Germany) with POS Combo Type 20 tablets (Beckman Coulter, USA) and Multiscan FC spectrophotometer (Thermo Scientific, Finland) with Microlatest tablets (PLIVA-Lachema, Czech Republic). Antimicrobial resistance was determined by discdiffusion method and using microbiological analyzer WalkAway 96 (Siemens, Germany). Minimal inhibitory concentrations for colistin were determined using the “MIC Colistin” kit (Erba Mannheim, Czech Republic). Detection of carbapenemases genes (KPC, OXA-48 group, IMP, VIM and NDM) was performed by RT-PCR using CFX-96 machine (Bio-Rad, USA) and commercial kits «MDR KPC/OXA-48-FL» and «MDR MBL-FL» (AmpliSens, Russia). Results. More than 90% of K. pneumoniae isolates in Nizhny Novgorod were resistant to III–V generation cephalosporins, 53.8% – to gentamicin, 71.2% – to ciprofloxacin, 81.2% – to co-trimoxazole, 88.1% – to ertapenem, 37.1% – to doripenem, 21.6% – to imipenem, 34.3% – to meropenem, 3.2% – to colistin. Genes of КРС-like carbapenemases were detected in 13.1% of isolates, OХA-48 – in 21.6%. Metallobeta-lactamases were not identified among tested isolates. Conclusions. Currently, there are no antimicrobials that active against all K. pneumoniae isolates in Nizhny Novgorod. Carbapenems and polymyxins remain active against more than 50% of isolates.

Objective. To determine frequency of Staphylococcus isolation and antimicrobial resistance in hospitalized children with different types of infections. Materials and Methods. Species identification and antimicrobial susceptibility testing in staphylococci were performed on a WalkAway 96 analyzer using Pos Combo type 20 tablets, and mecA gene detection was performed on a RotorGene 6000 amplifier with a set of AmpliSens MRSA-screen FL. Results. A total of 876 strains of staphylococci isolated in children’s hospitals were tested. The species and antibiotic resistance of Staphylococcus aureus and coagulase-negative staphylococci were studied. The most common types of staphylococci were: S. aureus – 36.0%, S. epidermidis – 23.0%, S. haemolyticus – 19.7%, S. hominis – 14.0%. As many as 35.3% of isolates were methicillin-resistant, while 32.9% of methicillin-resistant S. aureus was detected, and 65.6% of methicillin-resistant strains were among the most frequently isolated coagulase-negative staphylococci. The mecA gene was detected in 97.1% of phenotypically methicillin-resistant strains. Antibiotic resistance of S. aureus and coagulase-negative staphylococci circulating in children’s hospitals is very high. Two strains of S. aureus with intermediate resistance to vancomycin (MIC = 4 mcg/ml) and one S. aureus with resistance to linezolid (MIC = 8 mcg/ ml) were isolated. Among coagulase-negative staphylococci, two strains with intermediate resistance to vancomycin (MIC = 8 mcg/ml), two resistant to vancomycin (MIC = 16 mcg/ml), and 6 strains resistant to linezolid (MIC from 8 to 32 mcg/ml) were identified. Conclusions. Antimicrobial resistance of staphylococci in children’s hospitals does not depend on the species, more than half of the isolated isolates are methicillin-resistant. During the reporting period, staphylococci resistant to vancomycin and linezolid were identified, which requires resistance mechanisms to be determined.

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