Extrachromosomal resistance in Gram-negative organisms: the evolution of β-lactamase

摘要: beta-Lactamases are the major defense used by bacteria to overcome effects of penicillins, cephalosporins and related beta-lactam antibiotics. In antibiotic era, enzymes have evolved become more prevalent, appear in new hosts, be expressed at higher levels, acquired plasmids change catalytic properties increase affinity for what were meant nonhydrolysable substrates or reduce beta-lactamase inhibitors.