one of a group of drugs that includes the penicillin and the cephalosporin. All have a four-membered beta-lactam ring as part of their molecular structure. Beta-lactam antibiotics function by interfering with the growth of the cell walls of multiplying bacteria. Bacteria become resistant to these antibiotics by producing beta-lactamases, enzymes (such as penicillinase) that disrupt the beta-lactam ring. To counteract this, beta-lactamase inhibitors (e.g. clavulanic acid) may be added to beta-lactam antibiotics. For example, co-amoxiclav (Augmentin) is a mixture of amoxicillin and clavulanic acid.
Medical dictionary. 2011.