Antibiotics are the most effective drugs for curing bacteria-infectious diseases clinically.  They have a wide market due to their advantages of good antibacterial effect with limited side effects.  Among them, the beta-lactam class of antibiotics (for example, penicillins, cephalosporins, and carbapenems) are widely used because they have a strong bactericidal effect and low toxicity. 
To counter the efficacy of the various beta-lactams, bacteria have evolved to produce variants of beta-lactam deactivating enzymes called beta-lactamases, and in the ability to share this tool inter- and intra-species.  These beta-lactamases are categorized as “serine” or “metallo” based, respectively, on presence of a key serine or zinc in the enzyme active site.  The rapid spread of this mechanism of bacterial resistance can severely limit beta-lactam treatment options in the hospital and in the community.  Currently available beta-lactamase inhibitors (for example, clavulanic acid and tazobactam) are poorly active against the diversity of beta-lactamase enzymes (both serine- and metallo-based) now emerging clinically.  There is an urgent need for new beta-lactamase inhibitors with broadened enzyme spectrum.