Tracing of New Delhi Metallo-Beta-Lactamase-1 (NDM-1)-producing Klebsiella pneumoniae among carbapenem resistant clinical isolates at a university hospital in Iran

Background: New Delhi metallo-beta-lactamase-1(NDM-1) is a novel type of metallo-beta-lactamase (MBL)which inactivates all β-lactam antibiotics except aztreonam. Enterobacteriaceae expressing NDM-1 have been identified worldwide. The aim of this study was to detect MBLs in carbapenem-resistant K. pneumoniae isolatesobtained from patients hospitalized in one of the university hospitals in Isfahan, Iran. Methods: Of 112 isolates obtained from various clinical samples, 49 were selected for carbapenemase detection based on their reduced susceptibility to imipenem or meropenem according to the disc diffusion method. Theseisolates were screened for carbapenemase and MBL production using the Modified Hodge Test (MHT) andEpsilometer test (E-test) MBL strips. Polymerase chain reaction (PCR) was performed on all 49 isolates usingspecific primers to detect genes encoding IMP (active on imipenem), VIM (Verona integron-encoded metallo-β- lactamase), SPM-1 (Sao Paulo metallo-β-lactamase) and NDM-1. Results: Among 49 carbapenem resistant isolates, 32 (65.3 %) were positive for MHT and 6 (12.2 %) werefound positive for blaNDM-1. Other MBL genes were not detected. Conclusion: This is the second report on the detection of blaNDM-1 in Iran since it was first reported by Shahcheraghi and colleagues in 2012. This study indicated that resistance to carbapenems and isolation of bacteria producing NDM-1 is increasing. Therefore, the rapid detection of isolates expressing NDM-1 is essential to control their spread

Tracing of New Delhi Metallo-Beta-Lactamase-1 (NDM-1)-producing Klebsiella pneumoniae among carbapenem resistant clinical isolates at a university hospital in Iran Keywords:

New Delhi metallo-beta-lactamase-1 , Klebsiella pneumoniae , Carbapenem , Modified Hodge Test , Epsilometer test