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With significant human and economic losses, increasing bacterial resistance is a serious global threat to human life. Due to their high efficacy, broad spectrum, and cost-effectiveness, beta-lactams are widely used in the clinical management of bacterial infection. The emergence and wide spread of New Delhi metallo-β-lactamase (NDM-1), which can effectively inactivate β-lactams, has posed a challenge in the design of effective new antimicrobial treatments. Medicine repurposing is now an important tool in the development of new alternative medicines. We present a known glaucoma therapeutic, betaxolol (BET), which with a 50% inhibitory concentration (IC50) of 19.3 ± 0.9 μM significantly inhibits the hydrolytic activity of the NDM-1 enzyme and may represent a potential NDM-1 enzyme inhibitor. BET combined with meropenem (MEM) showed bactericidal synergism in vitro. The efficacy of BET was further evaluated against systemic bacterial infections in BALB/c mice. The results showed that BET+MEM decreased the numbers of leukocytes and inflammatory factors in peripheral blood, as well as the organ bacterial load and pathological damage. Molecular docking and kinetic simulations showed that BET can form hydrogen bonds and hydrophobic interactions directly with key amino acid residues in the NDM-1 active site. Thus, we demonstrated that BET inhibited NDM-1 by competitively binding to it and that it can be developed in combination with MEM as a new therapy for the management of infections caused by medicine-resistant bacteria. [ABSTRACT FROM AUTHOR]

Background: Antibiotic resistance in bacteria mediated by New Delhi Metallo-β-lactamase (NDM) is a global threat to human health with an enormous economic burden. NDM can hydrolyze all the β-lactam core-containing antibiotics including carbapenems, which are regarded as last resort antibiotics. Materials and Methods: A library of Abyssomicins was virtually screened to identify novel non-β-lactam ring-containing inhibitors of NDM-1. Different computational approaches such as molecular modeling, virtual screening, molecular docking, molecular dynamics simulation, ADMET profiling, and free energy calculations were utilized for this purpose. Results: Virtual screening and ADMET profiling shortlisted Abyssomicin W and Neoabyssomicin B as the most promising candidate molecules. An in-depth analysis of protein-ligand interactions by molecular docking revealed that both ligands bind the active site of NDM-1. The identified inhibitors interacted with key catalytic residues as well as other residues around the active site of NDM-1. Hydrogen bonding and hydrophobic interactions played a significant role in stabilizing the protein-inhibitor complexes. The docking energy of NDM-1-Abyssomicin W, and NDM-1-Neoabyssomicin B complexes were − 9.6 kcal/mol and − 9.5 kcal/mol, respectively, which were higher than NDM-1-Methicillin (control) complex (−7.3 kcal/mol). Molecular dynamics simulation and free energy calculations by MM-PBSA also confirmed the stability of NDM-1-Abyssomicin W, and NDM-1-Neoabyssomicin B complexes. Conclusion: The findings of this study suggest that Abyssomicins serve as potential inhibitors of NDM-1. However, these results need to be validated in vitro and in vivo. This study may serve as a basis for further developing Abyssomicins as novel inhibitors of β-lactamases. [ABSTRACT FROM AUTHOR]