Evolution and Dissemination of β-Lactamases Accelerated by Generations of β-Lactam Antibiotics

β-Lactamases are the principal mechanism of bacterial resistance to β-lactam antibiotics. In recent years the number and variety of new β-lactamases detected has risen at an alarming rate, apparently in response to the clinical use of novel classes of β-lactam antibiotics. This paper reviews the structure and evolution of β-lactamases in an attempt to understand the pressures that have contributed to their emergence.