Epidemiological and Genetic Overview of the Klebsiella pneumoniae Carbapenemases (KPCs) in K. pneumoniae Isolated from the Clinical Samples in Iran

Abstract

Background:The prevalence of carbapenem-resistant Enterobacteriaceae, especially Klebsiella pneumoniae carbapenemase (KPC), has been recently reported worldwide. Therefore, there is an indispensable need for precise and rapid detection of these carbapenemases. Objectives: This study was aimed to propose an accurate and rapid method for detecting K. pneumoniae carbapenemase genes from clinical samples, using reverse transcriptionpolymerase chain reaction (RT-PCR) and to evaluate the expression of these genes in the presence of β-lactam antibiotic by real-time PCR assay. Methods: One hundred and eighty-one K. pneumoniae strains were collected from patients presenting to Firoozgar Hospital of Tehran, Iran. The strains were tested using the disk diffusion method, the modified Hodge test (MHT), and E-test minimum inhibitory concentration (MIC). Next, reverse transcription-PCR method was applied for the identification of bla OXA-23 and bla OXA-48 genes. Finally, expression of genes was measured by real-time PCR assay in the presence and absence of β-lactam antibiotic. Results:Phenotypic testing showed a high level of antibiotic resistance, while the genotypic methods indicated the presence and expression of carbapenemase genes. Conclusions: The findings suggest revisions in the current antibiotic therapy protocols, considering the high expression level of resistant carbapenemases to K. pneumoniae strains.