Molecular characterization of carbapenem-resistant strains of Klebsiella pneumoniae isolated from Iranian patients: first identification of blaKPC gene in Iran.

Multi-resistant Klebsiella pneumoniae has been considered a serious global threat. This study was initiated to investigate carbapenem resistance among K. pneumoniae isolates in Iran and to detect carbapenemases in resistant strains. From 2009 to 2012, 180 K. pneumoniae strains were collected from Tehran hospitals. Of the isolates, 42 isolates (23.3%) were resistant to meropenem, 29 isolates (16.1%) were resistant to ertapenem, and 14 isolates (7.7%) were resistant to imipenem. All of carbapenem-resistant isolates were also resistant to the third generation of cephalosporins. modified Hodge test was positive in 25 (59.5%) of carbapenem-resistant isolates showing carbapenemase production. bla(NDM) and bla(VIM) genes were identified in three and five carbapenem-resistant isolates, respectively. One isolate showed presence of bla(KPC) gene. Class 1 integrons were detected in 14 carbapenem-resistant isolates. The most important finding about class 1 integrons was identification of an integron containing metallo-β-lactamase gene VIM-1 that also harbored dfrA27 and arr3 genes. It is important to note that K. pneumoniae carbapenemase and New Delhi metallo-beta-lactamase-positive isolates identified in this study showed resistance to the majority of routine antimicrobial agents, including all β-lactams and other classes of antibiotics. To our knowledge, this is the first identification of bla(KPC) and bla(VIM-1) genes among isolates of K. pneumoniae in Iran.