Molecular and genetic analysis of Klebsiella pneumoniae clinical isolates in patients with circulatory system diseases

Relevance. In patients with circulatory system diseases, Klebsiella pneumoniae isolates carrying both hypervirulence and multidrug resistance are one of the most common causative agents of healthcare-associated infections (HAI). The main sequence types (ST395, ST307) of Klebsiella pneumoniae are shown, virulence marker genes (AbST, YbST and RmST), determinants of beta-lactam resistance (bla , bla , bla ), including carbapenems (bla , are identified.

Aim. To investigate the determinants of antibiotic resistance and virulence markers of clinical isolates of Klebsiella pneumoniae in patients with circulatory system diseases (CSD).

Materials and methods. We studied 69 isolates of Klebsiella spp., collected from November 2022 to October 2023 from samples of pathological materials from patients of two large centers for the treatment of patients with CSD who had registered cases of HAIs according to NASCI criteria. The species identity of isolates to the Klebsiella spp. genus confirmed by mass spectrometry. PCR was used to determine the presence or absence of carbapenemase and aerobactin genes for strain typing. Antibiotics susceptibility was determined by the disk diffusion method and broth microdilution method. The complete set of genes determining resistance and virulence was identified in 17 Klebsiella pneumoniae isolates using whole genome sequencing. Functional annotation of genomes was performed by the bioinformatic resource Kleborate v3. and Kaptiv.

Results. The studied Klebsiella pneumoniae strains were characterized by different degrees of phenotypic drug resistance: predominantly broad/extreme XDR) – 78.57 %, multiple (MDR) – 14.29 %, pan-resistance (PDR) –7.14 %. Klebsiella pneumoniae (n = 17) for which whole genome sequencing was performed belong to 4 sequence types: to ST395 – 11 isolates (64.71 %), to ST307 – 4 (23.53 %), and one of each to ST416 and ST6 (5.88 % each). Sequence-type ST395 isolates demonstrated the properties of resistance to classes 13–14 of antibiotics, ST307 to classes 9, ST416 and ST6 did not have resistance to antibiotics. A high prevalence of the hypervirulent Klebsiella pneumoniae (hvKP) pathotype was observed: rmpA2 (82.35 %), iucA (82.35 %), a hypermucoid phenotype (Hm, 58.93 %) and carbapenem resistance (mediated by OXA-48 carbapenemase, 64.71 %).

Conclusion. Analyzed Klebsiella pneumoniae isolates are represented by 4 sequence types, widespread in European countries. HvKP isolates characterized by XDR, PDR and simultaneously carrying carbapenem resistance genes require prompt and accurate diagnosis to effectively treat patients with CSD.

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