Mechanism of imipenem resistance in metallo-β-lactamases expressing pathogenic bacterial spp. and identification of potential inhibitors: An in silico approach.

The World Health Organization reports that millions of people around the world are infected with antibiotic-resistant bacteria. Such resistance is more common in Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae strains because of the expression of the metallo-β-lactamases (MBLs) namely Imipenemase (IMP)-1, IMP-2, New Delhi metallo-β-lactamases-, Verona imipenemase (VIM)-4, VIM-5, and VIM-7. We did an in silico analysis to understand the resistance mechanism of imipenem at the structural level. Our modeling studies reveal that the VIM-4-imipenem complex has highest binding energy and forms a stable complex as indicated by a consensus score (C-score) value of 5.44. The intense interaction between the substrate and the β-lactamases leads to the increased hydrolysis of the substrate resulting in rapid hydrolysis of the antibiotic imipenem by VIM-4. Virtual screening of compounds from the ZINC database targeting VIM-4 was done, and we found compound ZINC44608383 as the high binding energy compound with the C-score value of 5.58. This compound could be exploited for inhibitor design and development. The current study helps us to understand the resistance mechanism of imipenem in MBL-expressing strains. Also, we have identified a probable inhibitor for VIM-4. We believe that our results will be useful for researchers in designing potent inhibitors for VIM-4.