Medicinal chemistry of β-lactam antibiotics

Abstract

The β-lactam class of antibacterials is a cornerstone of human health. For nearly eight decades, their unparalleled clinical efficacy and clinical safety have made the β-lactam class preeminent in the treatment of bacterial infection. The relatively brief period in human history during which the β-lactams have exerted this benefit is a period characterized by continuous medicinal chemistry innovation, seen visibly in the progression from the penicillins to the complex ensemble of β-lactams (now including also cephalosporins, monobactams, and carbapenems) used in the clinic. The key force behind this innovation is the progressive evolution by bacteria of resistance mechanisms. Today, highly resistant bacteria challenge the way medicinal chemists contemplate the creative alteration of β-lactam structures, the way the pharmaceutical industry develops β-lactams (and other antibacterial) structures, and the way the medical community uses antibacterials. This article gives a concise summary of the history of the β-lactams. Its emphasis is recent structural innovation with respect to the β-lactams, and with respect to structurally related classes that act to preserve the clinical activity of the β-lactams through inhibition of bacterial β-lactam-hydrolyzing, and thus β-lactam-deactivating, enzymes. We integrate these chemistry advances with new biological discoveries with respect to the bactericidal mechanism of the β-lactams and with respect to bacterial resistance mechanisms. The combination of these perspectives is a foundational perspective to guide the medicinal chemistry future of the β-lactams.