Since 2018, Klebsiella pneumoniae isolates have been described in Russia, demonstrating the convergence of hypervirulent properties and multiple antibiotic resistance. The problem of the Klebsiella hypervirulent pathotype has been actualized relatively recently that was progressively described in the 1980s in the Pacific region. These Klebsiella spp. can cause serious community-acquired infections in healthy people, which fundamentally differs from the classic Klebsiella pathotype initially preserving sensitivity to most antibacterial drugs. In 20182020, there were reported detection of hypervirulent K. pneumoniae isolates in the Russian Federation. Like multiple resistance, hypervirulence is associated with the acquiring additional genetic material and formation of genetic lineages that effectively support such acquired determinants. For a long time, it was believed that the convergence of multiple resistance and hypervirulence is unlikely due to a large genetic burden as well as different ecological strategies in same species. The spread of hypervirulent strains, primarily in the Asian region, is associated with the conserved plasmids of the pLVPK group. The conservatism of both the originally discovered virulence plasmids (such as pLVPK and pK2044) and the genetic lineages associated with them (mainly CG23) is probably determined by the absence of a gene cluster responsible for conjugation in these plasmids. The driver of the spread of non-conjugative plasmids with determinants of hypervirulence is clonal spread, not horizontal gene transfer. Nevertheless, after a sufficiently long period of circulation of plasmids bearing markers of hypervirulence (described since 1986) in Klebsiella, a relatively limited number of genetic lineages, there were events of mobilization of the determinants of hypervirulence and, as a consequence, the inclusion in horizontal gene transfer in the population (described cases in 2016 ), which led to a sharp increase in the number of genetic lineages and variants of genetic platforms carrying hypervirulence genes. In Russia, first cases of hv-MDR-Kpn were described in 2018 in Moscow based on analyzing collection of Klebsiella isolated in 20122016. In 2020 and 2021, similar cases were described in St. Petersburg. In case of repeated pessimistic scenario observed over the last decade due to spread of carbapenemases, effectiveness of health care will be more than substantially harmed.

The rapid spread of gram-negative bacteria resistance to carbapenems due to the production of carbapenemases requires new treatment options. The activity of carbapenem antibiotic biapenem, recently registered in Russia, against producers of various carbapenemases was studied in comparison with other antibiotics of this group. Among NDM-type carbapenemase producers, 77.8% demonstrated clinical susceptibility to biapenem; 50.3% and 21.1% of isolates were susceptible to meropenem and imipenem, respectively. Among the producers of OXA-48-type carbapenemases, 82,6%, 60,9%, and 65,2% of isolates demonstrated susceptibility to biapenem, imipenem, and meropenem, respectively.Producers of KPC-type carbapenemases were 100% resistant to all carbapenems. The introduction of biapenem will significantly expand the possibilities of treating severe infections caused by carbapenemase producers.

Escherichia coli isolates from various sources from 2018 to 2019 were included in the study. Mcr-1 genes were found in two of 105 animal strains (2%) and seven of 928 human strains (0.8%). All mcr-1-positive strains showed a low level of resistance to colistin (MIC ranged from 4 to 8 µg/ml). Both strains isolated from animals remained sensitive to betalactam antibiotics and did not contain beta-lactamase genes. Beta-lactamases were absent only in one of the strains isolated from humans. Four strains were resistant to cephalosporins with sensitivity to carbapenems and carried class A (blaCTX-M-15 or blaCTX-M-1) or class C (blaCMY-2) extended-spectrum beta-lactamases genes. One strain showed resistance to cephalosporins and meropenem and contained four beta-lactamase genes: blaNDM-1, blaCTX-M-15, blaTEM-1B, and blaCMY-6. Only one strain isolated from animals remained sensitive to ciprofloxacin, the rest showed high level of resistance, had amino acid substitutions in the DNA gyrase genes or mutations leading to overexpression of the mdfA gene. In terms of resistance to aminoglycosides, the strains varied widely and carried up to four aminoglycoside-modifying enzyme genes. One strain isolated from humans showed resistance to tigecycline, but no genes conferring resistance to this antibiotic were found. The data obtained substantiate the need for extended studies on the molecular epidemiology of associated resistance to polymyxins and beta-lactams.

The nucleotide sequence of a bla _KPC-2 -harboring plasmid (pKPCAPSS) from Klebsiella pneumoniae ST273 isolated in Saint Petersburg, Russia, from a patient with history of recent travel to Vietnam is presented. This 127,970-bp plasmid possessed both IncFII and IncR replicons. bla _KPC-2 was localized on a hypothetical mobile element. This element was flanked by 38-bp inverted Tn 3 repeats and included a Tn 3 -specific transposase gene, macrolide resistance operon ( mphA-mrx-mphR ), and a fragment of bla _TEM with unique polymorphisms.

Infectious complications caused by antibiotic-resistant strains in burn-injury patients account for 30–75% of all deaths. For optimal clinical contro

Background/Objectives: Providencia stuartii is intrinsically resistant to several antibiotic classes, and acquisition of bla_NDM further restricts treatment options. This study aimed to characterize NDM-producing P. stuartii isolates from a small hospital cluster in Russia and to place them within the global genomic context. Methods: Four isolates recovered between June and July 2023 from a single hospital were analyzed using Illumina and Oxford Nanopore sequencing to assess genetic relatedness and plasmid content. Results: The isolates showed identical extensively drug-resistant profiles and were closely related genomically. All carried nearly identical IncC plasmids harboring multiple antimicrobial resistance genes, including bla_NDM. Comparative analysis indicated that these genomes clustered with recent European isolates but differed in the bla_NDM allele and its genomic location. Highly similar IncC plasmids were also found in our previous Klebsiella pneumoniae dataset, demonstrating that this plasmid backbone occurs in multiple bacterial species in the region. Conclusions: The study highlights the role of IncC plasmids in carbapenemase dissemination and underscores the value of genomic surveillance integrating chromosomal and plasmid analyses to track extensively drug-resistant pathogens.