Evaluation of the usefulness of selected methods for the detection of carbapenemases in Klebsiella strains

Abstract

Introduction. Klebsiella rods, belonging to the family Enterobacteriaceae, are generally opportunistic pathogens commonly associated with nosocomial infections, especially in intensive care units. Interestingly, strains of this genus also show multi-drug resistance. In recent years, multiple studies have indicated that the prevalence of carbapenem resistance has increased rapidly among Klebsiella representatives. Aim. The aim of this study was to assess the usefulness of selected phenotypic and genotypic methods for the detection of the most important carbapenemases in Klebsiella strains. Methodology. The study involved 51 Klebsiella strains. The ability to produce carbapenemases was determined by phenotypic methods (double disc synergy test, test with four discs and three inhibitors, CarbaNP test, culture on chromogenic medium, panels of automatic method - Phoenix, CIM test and modified Hodge test). The potential for carbapenemase synthesis was also evaluated using real-time PCR, detecting blaVIM/IMP, blaKPC, blaNDM and blaOXA-48 genes. Results. Using the phenotypic methods, positive results were obtained for all of the analysed strains. Using PCR, carbapenemase synthesis potential was confirmed on the molecular level; the blaVIM gene was detected in 23 strains, the blaNDM gene in 26 strains and the blaOXA-48 gene in two strains. Conclusion. There was complete agreement between the carbapenemases detected by the genetic method and the results obtained with phenotypic methods.