Microbiological and molecular genetic characteristics of Klebsiella pneumoniae isolates, extracted under conditions of cardiac surgery hospital

Abstract

Klebsiella pneumoniae is one of the main causative agents of healthcare-associated infections (HAI) worldwide. The study was aimed at molecular characterization of beta-lactam antibiotic resistance in K. pneumoniae isolated in the cardiac surgery hospital, identify hypervirulent isolates and assess isolate genetic relatedness. K. pneumoniae isolated from the clinical material of patients (n = 50) at cardiac surgery departments as well as anesthesiology and reanimation department treated at the cardiovascular surgery hospital in Perm from July 2021 to December 2022 were analyzed. Bacteriological studies were performed on an automatic analyzer WalkAway-96Plus (Beckman Coulter, USA). The sensitivity to thirteen antimicrobials, production of extended-spectrum beta-lactamases (ESBL) and multidrug resistance (MDR) phenotype were assessed. The string test was used to screen hypermucoviscous K. pneumoniae. Isolate relatedness (ERIC-PCR), presence of beta-lactamase genes (blaTEM, blaCTX-M, blaSHV, blaOXA, blaKPC, blaVIM-2, blaIMP-1, blaNDM-1), as well as genes associated with hypervirulence (prmpA, iucA, peg-344, wzyK2, magA) were analyzed by PCR. Amplifications were performed in a DNA Engine Dyad Thermal Cycler (Bio-Rad, USA). Gel documentation system Gel-Doc XR (Bio-Rad, USA) was used for band visualization and data documentation. According to the study results, it was found that carbapenem-resistant isolates accounted for almost 76% of all isolates, the ESBL-phenotype had 90%, and MDR-phenotype — 88% of studied isolates. According to the string test results, 8% of K. pneumoniae isolates had a hypermucoviscous phenotype. As for genes associated with hypervirulence, it was shown that the iucA gene was the most common, amplified in 54% of isolates, prmpA was detected in 38% of isolates, 48% of isolates had wzyK2 or magA genes encoding capsular type K1/K2. Almost a third of K. pneumoniae samples contained a combination of the rmpA and iucA genes, and they were isolated more often in the group of patients with active infection. Only carbapenem-sensitive microorganisms had hypermucoviscous phenotype, K1 capsular type, and a combination of prmpA, iucA, peg-344 genes, whereas the K2 capsular type was most common among carbapenem-resistant K. pneumoniae. Based on molecular genetic typing, it was found that 24% of K. pneumoniae isolates were assigned to four genome groups of identical cultures, 76% of the isolates had individual profiles. Closely related isolates were found among patients from different departments that indicates a potential pathogen circulation in the closed circuit “surgery department–department of anesthesiology” and “reanimation–surgery department”.