Antibiotic Resistance Among Klebsiella pneumoniae, Molecular Detection and Expression Level of blaKPC and blaGES Genes by Real-Time PCR

The prevalent emergence of carbapenem-resistant Enterobacteriaceae, especially Klebsiella pneumoniae carbapenemases (KPC) that causes infection associated with multidrug-resistant, is a major clinical and public health concern. Accurate and fast detection of carbapenemases is essential for effective infection control.

The aims of this study were the detection of blaKPC and blaGES genes with phenotypic and genotypic methods, evaluation of expression level of these genes in the presence and absence of β-lactam antibiotic, and determination of antibiotic resistance patterns among K. pneumoniae isolated at Firoozgar Hospital.

One hundred and eighty-one K. pneumoniae strains were collected from patients presenting to Firoozgar Hospital of Tehran, Iran from March 2018 to December 2018. The strains were tested using the disk diffusion method, modified Hodge test (MHT), and minimum inhibitory concentration (MIC). The presence of blaKPC and blaGES resistance genes was detected by RT-PCR. The blaKPC and blaGES genes expression level was measured by real-time PCR in the presence and absence of β-lactam antibiotic.

The results of this study showed the highest and lowest rates of resistance to cefepime and imipenem were 83.9% and 55.2%, respectively. 100 strains were positive as KPC-producing in MHT. Also, they exhibited resistance to imipenem by E-test. 51% and 49% of these 100 isolates were positive for blaKPC and blaGES genes, respectively. Real-time PCR assay showed the higher expression level of blaKPC (1.04 folds) and blaGES (12.21 folds) increase in resistant strains in the presence of imipenem.

Due to the high resistance of K. pneumoniae isolates to common antibiotics, hence, there is an urge for revisiting the antibiotic therapy protocols for prevention and control of the spread of resistant bacteria.