The emergence and spread of bacterial pathogens acquired metallo-β-lactamase (MBL) and serine-β-lactamase (SBL) medicated β-lactam resistance gives rise to an urgent need for the development of new dual-action MBL/SBL inhibitors. Application of a pharmacophore fusion strategy led to the identification of (2′S)-(1-(3′-mercapto-2′-methylpropanamido)methyl)boronic acid (MS01) as a new dual-action inhibitor, which manifests broad-spectrum inhibition to representative MBL/ SBL enzymes, including the widespread VIM-2 and KPC-2. Guided by the VIM-2:MS01 and KPC-2:MS01 complex structures, further structural optimization yielded new, more potent dual-action inhibitors. Selectivity studies indicated that the inhibitors had no apparent inhibition to human angiotensin-converting enzyme-2 and showed selectivity across serine hydrolyases in E. coli and human HEK293T cells labeled by the activity-based probe TAMRA-FP. Moreover, the inhibitors displayed potentiation of meropenem efficacy against MBL-or SBL-positive clinical isolates without apparent cytotoxicity. This work will aid efforts to develop new types of clinically useful dual-action inhibitors targeting MBL/SBL enzymes.

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Resistance to β‐lactam antibacterials is commonly associated with the production of the serine β‐lactamases (SBLs) and/or metallo‐β‐lactamases (MBLs). Although clinically useful inhibitors for the SBLs have been developed, no equivalent inhibitors are available for the MBLs, which can hydrolyze almost all β‐lactam antibiotics, including the so‐called “last resort” carbapenems. It is still a challenging task to develop a clinically useful inhibitor that should be broad‐spectrum targeting multiple clinically relevant MBL enzymes that differ in their active site features. This review provides a detailed description of interaction modes of substrates and small‐molecule inhibitors with various MBL enzymes and highlights the importance of metal‐ and “anchor residue”‐binding features to achieve broad‐spectrum MBL inhibition. Recently emerging active site interference strategies include metal ion deprivation, metal ion replacement, and cysteine modification as challenging, but worth experimenting directions for inhibitor development. The metalloenzyme selectivity, metal‐binding pharmacophore, and cellular permeability and accumulation should be properly considered in the further development of clinically useful inhibitors to combat MBL‐mediated antibacterial resistance.

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