Comparison of Prevalence of blaNDM-1 Gene among Metallo-Beta Lactamase-Producing Multidrug-Resistant Fermenters and Nonfermenters in a Tertiary Care Hospital

Abstract

Background and Aim: Metallo-beta-lactamases (MBLs) which open β-lactam ring with help of metal cofactor degrade all the classes of β-lactams except monobactams and are notable for their constant and efficient carbapenemase activity. New Delhi Metallo-beta-lactamase (NDM) is type of carbapenemase which is able to inactivate all β-lactams except aztreonam. Combined disk synergy test (CDST) and polymerase chain reaction (PCR) analysis are used for the detection of MBL production. Materials and Methods: All clinical specimens received in the microbiology department for culture and sensitivity from indoor patients were included in study. Brief history and related data of the patients was being recorded. The direct Gram staining and samples were inoculated on culture media and incubated at 37°C for 18–24 h. Biochemical reactions were performed and the antibiotic susceptibility test was performed by Kirby–Bauer Disk-Diffusion method and VITEK 2. All the multidrug-resistant (MDR) Gram-negative bacteria (GNB) which were carbapenem resistant subjected to CDST and Genotypic detection of NDM-1 by PCR was done. The association between categorical variables was explored using the Pearson’s Chi-square test. Results: The present study was conducted on 260 GNB isolated from 5307 specimens, 164 were MDR, 68 were carbapenem resistant, and 48 were found to be MBLs (19 were fermenters; 29 were nonfermenters). Thirty-six blaNDM-1 gene was isolated from both MDR fermenters and nonfermenters. The positivity of CDST in detecting blaNDM-1 positive MBLs taking PCR as the gold standard was 75%. Conclusion: NDM-1 carrying isolates disseminate quickly even among the organisms of different genera, their presence in high proportion could further threaten the public health and put an end to our current pharmacopoeia.