Comparative genomic analysis of clinical isolates of <i>Klebsiella pneumoniae</i> isolated from newborns with different outcomes of the infectious process in the neonatal period

Introduction. Some progress has been made in the study of the molecular mechanisms of antibiotic resistance, namely, genes and their variants have been identified that ensure the inactivation of beta-lactam antibiotics. Nevertheless, there is still a necessity for further studies of genetic diversity of nosocomial strains, prevalence of genetic determinants of resistance to other groups of antibiotics, virulence factors and realization of pathogenic potential by opportunistic microorganisms. Aim of the study was to compare the genetic profile of clinical isolates of Klebsiella pneumoniae isolated from newborns with different outcomes of the infectious process in the neonatal period. Materials and methods. Using whole-genome sequencing and bioinformatic analysis to search for determinants of resistance and virulence, 3 strains of K. pneumoniae were studied, 2 of which were isolated from the blood of a generalized form of infection, 1 from the feces of a newborn child. Results. K. pneumoniae strains belonged to sequence types (ST) ST23, ST14 and ST3559, and differed in genetic determinants of antibiotic resistance and virulence factors. At the same time, they all had the genetic determinants fimH, mrkA and iutA, which are associated with an increased ability to attach to substrates and transport aerobactin. Strain 222 of ST3559, which has the largest number of antibiotic resistance genes, contained the smallest number of virulence factor genes, and vice versa, strain 144 of ST23, in which the smallest number of antibacterial drug resistance genes was detected, contained the most virulence factor genes. Conclusions. Identification of K. pneumoniae strains that differ in the genetic profile of antibiotic resistance and virulence in neonatal hospital patients indicates a complex interaction between bacteria and the macroorganism, in which isolates with low pathogenic potential can cause serious infectious complications, and vice versa, when a highly virulent strain does not realize its pathogenic potential, as demonstrated in case of K. pneumoniae strains ST14, ST3559 and ST23, respectively. This highlights the difficulty of effectively predicting and managing infection risks in hospital operations.