en Anti-microbial agents, resistance and treatment protocols Anti-microbial agents, resistance and treatment protocols Original article Original article <strong>Introduction: </strong>The emergence of extended-spectrum &beta;-lactamase (ESBL) and carbapenem-resistant <em>Enterobacteriaceae</em>, especially <em>Klebsiella pneumoniae</em> isolates, has become a severe concern worldwide. This study aimed to determine the prevalence of <em>blaVIM</em> and <em>blaNDM</em> genes among <em>K. pneumoniae</em> isolates. <strong>&nbsp;Methods: </strong>One hundred-eighty-one <em>K. pneumoniae</em> isolates were obtained from different clinical specimens of patients hospitalized at Firoozgar hospital, Tehran, Iran. The isolates were identified by standard biochemical tests, and their identity was confirmed by Vitek 2 (bioM&eacute;rieux, France), a fully automated system for bacterial&nbsp;identification. The isolates were subjected to antimicrobial susceptibility testing and screened for ESBL by double-disc synergy test (DDST) and modified Hodge test (MHT) for the detection of carbapenemase. PCR was also used to detect the presence of <em>blaVIM</em> and <em>blaNDM</em> resistance genes in the isolates.<strong> Results</strong>: The Vitek 2 system confirmed the biochemical test results. The highest and lowest rates of resistance to antibiotics belonged to cefepime (83.9%) and imipenem (55.2%).&nbsp; Eighty-six and 100 isolates showed to produce ESB and KPC by DDST and MHT, respectively. About 71% and 97% of the 100 isolates were positive for <em>blaVIM</em> and <em>blaNDM</em> genes, respectively.<strong> Conclusion:</strong> The high rate of ESBL- and KPC-producing <em>K. pneumoniae</em> isolates in our hospital setting revealed resistance to conventional antibiotics, which limit our options in choosing appropriate antimicrobials. Although the management of infections associated with these organisms is challenging, it is essential to control such strains to prevent the outbreak. Klebsiella pneumoniae, beta-Lactamases, Carbapenem-Resistant Enterobacteriaceae 50 55 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-238-1&slc_lang=en&sid=1 Narjes Mohammadi Bandari narjes_bandari@yahoo.com 0000000258977530 No Department of Biology, Qom Branch, Islamic Azad University, Qom, Iran Hossein Keyvani h.keyvani@yahoo.com 0000000180541939 No Department of Virology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Mohammad Abootaleb mohammad_abootaleb@yahoo.com 0000000154537653 Yes Department of Biology, Qom Branch, Islamic Azad University, Qom, Iran.