Molecular Epidemiology of Carbapenem-resistant Klebsiella pneumoniae Isolates

Aim Carbapenem-resistant Klebsiella pneumoniae infection has become an important clinical problem with reduced therapeutic options. This study aimed to investigate the carbapenem resistance rates and responsible resistance genes in K. pneumoniae isolates derived from clinical samples collected in Istanbul. Materials and Methods This prospective study included a total of 1452 K. pneumoniae isolates from patients admitted to our hospital between July 2013 and July 2014. VITEK-2 (bioMérieux, MarcyI’？toile, France) was used for microbial identification and antimicrobial susceptibility testing. The carbapenem-resistant isolates identified by VITEK-2 were also found to be resistant to ertapenem by the ertapenem gradient test. Resistance mechanisms of the carbapenem-resistant isolates were investigated using real time-polymerase chain reaction. Results Of the 1452 K. pneumoniae isolates, 45 (3.1%) were carbapenem-resistant. Of these, 32 (71.1%) were blaOXA-48-positive, 9 (20%) blaNDM-positive, and 1 (2.2%) blaVIM-1-positive. None had the genes blaKPC and blaIMP-1. The greatest susceptibility by the isolated carbapenemase-producing K.pneu moniae was shown to the antimicrobials amikacin and gentamicin. Discussion and Conclusion In our hospital, there are several mechanisms causing carbapenem resistance, and the blaOXA-48 positivity rate of 71.1% is significant. This resistance may spread rapidly and, through enzymatic resistance gene transfer, lead to hospital epidemics difficult to manage. For this reason, accurate and rapid laboratory diagnosis is important in infection control. For faster results, molecular methods, as well as phenotypic methods, must be included in the hospital infrastructur