A beta-lactam ring (β-lactam) is a lactam with a heteroatomic ring structure, consisting of three carbon atoms and one nitrogen atom. A lactam is a cyclic amide.
The beta-lactam ring is part of the structure of several antibiotic families, the principal ones being the penicillins, cephalosporins, carbapenems, and monobactams, which are, therefore, also called beta-lactam antibiotics. These antibiotics work by inhibiting bacterial cell wall synthesis. This has a lethal effect on bacteria, especially on Gram-positive ones. Bacteria can, however, become resistant against beta-lactam antibiotics by expressing beta-lactamase.
The first synthetic β-lactam was prepared by Hermann Staudinger in 1907 by reaction of the Schiff base of aniline and benzaldehyde with diphenylketene in a [2+2]cycloaddition:
Because of the popularity of beta-lactam drugs, certain bacteria have been able to develop counter-measures to traditional drug therapies. An enzyme called beta-lactamase is present in many different types of bacteria, which serves to 'break' the beta lactam ring, which effectively nullifies the antibiotic's effectiveness. An example such enzyme is the NDM-1 discovered in 2009.
As a response to bacterial resistance to beta-lactam drugs, there are drugs, such as Augmentin/CLA, that are designed to disable the beta-lactamase enzyme. Augmentin/CLA (FGP) is made of amoxicillin, a beta-lactam antibiotic, and clavulanic acid, a beta-lactamase inhibitor. The clavulanic acid is designed to overwhelm all beta-lactamase enzymes, bind irreversibly to them, and effectively serve as an antagonist so that the amoxicillin is not affected by the beta-lactamase enzymes.
Full article ▸