Pterostilbene restores carbapenem susceptibility in New Delhi metallo‐β‐lactamase‐producing isolates by inhibiting the activity of New Delhi metallo‐β‐lactamases

Abstract

Background and PurposeBacteria producing New Delhi metallo‐β‐lactamase‐1 (NDM‐1) are an increasing clinical threat. NDM‐1 can inactivate almost all β‐lactams and is not sensitive to any existing β‐lactamase inhibitors. To identify effective inhibitors of the NDM‐1 enzyme and clarify the mechanism of action, a “lead compound” for developing more potent NDM‐1 inhibitors needs to be provided.Experimental ApproachNatural compounds were tested by enzyme inhibition screening to find potential inhibitors. MIC assays, growth curve assays, and time‐kill assays were conducted to evaluate the in vitro antibacterial activity of pterostilbene and the combination of pterostilbene and meropenem. A murine thigh model and a mouse pneumonia model were used to evaluate the in vivo efficacy of combined therapy. Molecular modelling and a mutational analysis were used to clarify the mechanism of action.Key ResultsPterostilbene significantly inhibited NDM‐1 hydrolysis activity in enzyme inhibition screening assays and effectively restored the effectiveness of meropenem in vitro with NDM‐expressing isolates in antibacterial activity assays. In addition, the combined therapy effectively reduced the bacterial burden in a murine thigh model and protected mice from pneumonia caused by Klebsiella pneumoniae. By means of molecular dynamics simulation, we observed that pterostilbene localized to the catalytic pocket of NDM‐1, hindering substrate binding to NDM‐1 and reducing NDM‐1 activity.Conclusions and ImplicationsThese findings indicated that pterostilbene combined with meropenem may offer a new safe and potential “lead compound” for the further development of NDM‐1 inhibitors.

Specific NDM-1 Inhibitor of Isoliquiritin Enhances the Activity of Meropenem against NDM-1-positive Enterobacteriaceae in vitro

“…The NDM-1-producing isolates E. coli ZC-YN3, K. pneumoniae QD-KP2 and E. coli BL21(DE3) (pET28a-NDM-1)( ndm-1 gene obtained from K. pneumoniae QD-KP2) were used as NDM-1-positive isolates for this study [19]. The NDM-1-negative strains E. coli BL21(DE3)(pET28a) and E. coli ATCC 25,922 were used as negative-control strains.…”

“…The NDM-1-negative strains E. coli BL21(DE3)(pET28a) and E. coli ATCC 25,922 were used as negative-control strains. In addition, E. coli ZC-YN5 (carried NDM-5) was described in our previous research [19].…”

Drug repurposing for next-generation combination therapies against multidrug-resistant bacteria

“…Ebselen can simultaneously bind to two sites in NDM-1 by forming an S-Se bond with Cys221 and an amide bond with Lys224, thus selectively inhibiting MBLs both in vitro and in vivo . Another inhibitor of MBLs is pterostilbene 148 , a polyphenol compound that was isolated from red sandalwood. It has been used as a natural dietary antioxidant and in other applications such as anticancer.…”

“…Molecular dynamic simulation revealed that pterostilbene is localized to the catalytic pocket of NDM-1 by forming a strong interaction with Trp93 and Asp124. Consequently, this hinders substrate binding to NDM-1 and reduces NDM-1 activity 148 . Furthermore, a high-throughput assay revealed that the inhibitor of topoisomerase II mitoxantrone effectively suppressed enzymatic activity of VIM 149 , through unknown mechanisms.…”

Colistin Combined With Tigecycline: A Promising Alternative Strategy to Combat Escherichia coli Harboring blaNDM–5 and mcr-1

“…Infections caused by carbapenem-resistant Enterobacteriaceae (CRE), especially the New Delhi metallo-β-lactamases (NDM)-producing Escherichia coli, have become a global therapeutic challenge in clinical and public health settings (Perez and Bonomo, 2018). In general, isolates carrying bla NDM tend to carry other resistance genes thus limiting treatment options (Falagas et al, 2014;Liu et al, 2019). Currently, the polymyxin antibiotics (polymyxin B and colistin) have reemerged as the last-line therapy against CRE.…”