Comparison of the Novel Oxa-48 and Kpc K-SeT Assay, and Blue-Carba Test for the Detection of Carbapenemase-Producing Enterobacteriaceae Using PCR as a Reference Method

Abstract

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.