The investigation of oxacillinase/metallo-beta-lactamase genes and clonal analysis in carbapenem-resistant Klebsiella pneumoniae.

Infections due to carbapenem-resistant Klebsiella pneumoniae represent a growing problem nationally. In our study, we aimed to examine carbapenem-resistant K. pneumoniae with multiple resistance isolated in the intensive care unit of our hospital. Isolates were investigated for the presence of oxacillinase and metallo-beta lactamase genes with a view to determining the clonal relationship between the strains intensely over a short period. Strain identification was completed with conventional methods and automated identification kit. OXA-58, OXA-23, OXA-51, OXA-24 and OXA-48 and metallo-beta lactamase genes IPM, VIM, SPM, SIM, GIM and NDM-1 were investigated with PCR. For clonal relationships of carbapenem-resistant strains, the PFGE experiment was performed. While all of these carbapenem-resistant strains were positive for OXA-48, the resistant genes NDM-1, VIM, KPC, IPM, SPM, GIM, SIM, OXA-23, OXA-24, OXA-58 and OXA-51 were not observed. When molecular typing results were investigated, PFGE determined clonal distribution of three pulsotypes. However, it was observed that the strains intensified in a single clone and this was assessed as the outbreak isolate. The results of this study showed the primary enzyme responsible for carbapenem resistance in K. pneumoniae strains in our hospital is still OXA-48. To prevent the spread of carbapenem-resistant K. pneumoniae isolates, with epidemic potential, national-level monitoring and effective infection control precautions should be enforced.