Investigation of New Delhi Metallo-Beta-Lactamase 1 (NDM-1) in Clinical Enterobacteriaceae Isolates in Southwest Iran

NDM-1 producing bacteria are highly resistant to beta-lactams, including carbapenems. So the emergence of these microorganisms becomes a problem for the health system. The aim of this study was to investigate the presence of NDM-1 by PCR in clinical isolates of Carbapenem-resistant Enterobacteriaceae (CRE) in the university-associated hospitals in Ahvaz city, southwest Iran. Between June 2014 to July 2015, 726 non duplicate isolates of Enterobacteriaceae species collected from different clinical samples from two university-affiliated hospitals in Ahvaz, southwest Iran. All isolates were subjected to antibiotic susceptibility testing according to CLSI 2014 principles and combined-disk test to phenotypic evaluation of MBL production. Gene encoding NDM-1 was screened by PCR. Of the 726 Enterobacteriaceae isolates, 72 isolates (9.9%) were resistant to carbapenems. Combined-disk test (CDT) was positive in 62 (86.1%) of the 72 carbapenem-resistant isolates suggesting Metallo-beta-lactamase production, of which. E. coli had highest rate (n=28, 45.2%) followed by K. pneumoniae (n=19, 30.7%). None of MBL producer Enterobacteriaceae was positive for the NDM-1 gene by PCR assay. This investigation performed on the NDM-1 gene in clinical isolates of Enterobactericeae in southwest Iran. Although the prevalence of CRE was low and NDM-1 positive Enterobacteriaceae were not detected in southwest Iran, it should be monitored regularly. Other possible Metallo-Beta-Lactamase should also be screened for better characterization of Carbapenem-resistant Enterobacteriaceae isolates.