Characterization of Resistance Genes and Polymerase Chain Reaction-Based Replicon Typing in Carbapenem-Resistant Klebsiella pneumoniae

Abstract

Background: Fifty isolates of Klebsiella pneumoniae isolated from clinical samples between 2012 and 2016 that were found to be resistant to carbapenems were included in this study. Materials and Methods: Resistance genes were investigated by performing PCR. Plasmid typing was performed using PCR-based replicon typing. The clonal relationships between the strains were investigated using pulsed-field gel electrophoresis (PFGE). Results: OXA-48-type carbapenemase genes were detected in 86% (n = 43/50) of K. pneumoniae isolates, whereas NDM-type carbapenemase genes were detected in 14% (n = 7/50) of the isolates. bla(TEM) was detected 60% (n = 30) of the strains, bla(SHV) in 78% (n = 39), bla(CTX-M-1) in 48% (n = 24), and bla(CTX-M-2)-type beta-lactamase in 10% (n = 5). bla(CTX-M-1) and bla(SHV) were concomitantly distributed in 40% (n = 20) of the strains, bla(TEM) and bla(SHV) in 54% (n = 27), bla(TEM), bla(SHV), and bla(CTX-M-1) in 32% (n = 16) and bla(CTX-M-1) and bla(CTX-M-2) in 10% (n = 5). Strain numbers 66, 69, 76, 77, and 78 coproduced carbapenemases, bla(CTX-M-1) and bla(CTX-M-2) in addition to bla(OXA-48) or bla(NDM-1) that were described as hybrid strains. IncR-type replicon was found in 50% (n = 25) of 50 isolates with plasmid typing, whereas IncA/C-type replicon was detected in 40% (n = 20) and IncFIIK-type replicon in 18% (n = 9) of the isolates. Outcomes of the transformation experiments showed that the OXA-48 gene was carried to the receiver cell on FII plasmids. No dominant epidemic clone was detected through PFGE. Conclusion: OXA-48 carbapenemase was found to be the most prevalent type of enzyme in our hospital, and the presence of NDM-1-type carbapenemase-carrying strain and an increase in their rate were detected.