Antimicrobial resistance and virulence of carbapenem-resistant <i>Klebsiella pneumoniae</i> strains isolated from children in intensive care and surgical units

Introduction. Infections associated with carbapenem-resistant (Carba-R) Klebsiella pneumoniae (KP) are a serious public health problem because they lead to an increase in hospital stays, treatment costs, and an increase in patient morbidity and mortality. Aim to characterize antimicrobial resistance, virulence factors and genotypes of Carba-R KP strains isolated from patients in intensive care and surgical units. Materials and methods. In total, 455 KP strains that were resistant to meropenem and/or imipenem, or susceptible to meropenem and/or imipenem at increased exposure were collected in 20182020. For further analysis, total 90 KP strains isolated from clinically significant sites blood/сerebrospinal fluid/urine/lower respiratory tract/wounds/abdominal cavity of patients in intensive care and surgical units were selected. Antibiotic susceptibility was determined using the broth microdilution method. Carbapenemase genes were detected by real-time PCR. The virulence genes and K1/K2 capsular serotypes were determined by multiplex PCR. Sequence types (ST) were determined using multilocus sequence typing. Results. Most of the selected isolates (97%) were recognized as extensively drug-resistant pathogens, three isolates were classified as multidrug-resistant pathogens. The major determinant of carbapenem resistance was blaOXA-48-like (53%), blaNDM-group was detected in 13% strains, a combination of blaNDM-group and blaOXA-48-like genes was found in 31% isolates. Two isolates harbored blaKPC-group. Most of the isolates had the virulence genes entB (100%), mrkD (99%), and ybtS (78%). The iutA gene was found in 16% strains. Four isolates had kfu gene and four strains carried rmpA gene. The K2 capsule type was determined in 13% isolates. Four ST dominated in the studied population: ST395 (26%), ST2975 (19%), ST198 (12%) and ST307 (11%). Conclusion. Carba-R KP isolates had a high level of resistance not only to carbapenems, but also to antibiotics of other classes. Carbapenem resistance was mainly associated with OXA-48 carbapenemase. The entB, mrkD and ybtS genes were the main determinants of virulence. The epidemically successful clones CG395 and CG307 were the predominant genetic lines. Resistance to antimicrobials was combined with the presence of various virulence factors. The data obtained are important for the epidemiological surveillance of the spread of KP and have important clinical implications.