BACTERIAL-RESISTANCE TO BETA-LACTAM ANTIBIOTICS

The historical development of antibiotic resistance, mechanisms of res istance, classification schemes for beta-lactamases, the clinical rele vance of resistance, and approaches to overcoming resistance are revie wed. The promise of eradication of infectious diseases has not been fu lfilled, in great part owing to the emergence of antibiotic-resistant organisms. Although genes for bacterial resistance may have existed be fore the clinical use of antibiotics, selection of new resistant strai ns is driven by the widespread use of antimicrobials in humans and ani mals. The most commonly prescribed antimicrobials in the United States are the p-lactam antibiotics, and the most common mechanism of bacter ial resistance to these agents is inactivation by beta-lactamase. The clinical and economic consequences of therapeutic failure and relapse- extended hospital stays, increased morbidity and mortality, and the us e of potentially more toxic and costly antimicrobial agents-require ne w strategies to prevent the spread of resistant organisms and to limit future resistance.