title: Evolution and clinical importance of extended-spectrum beta-lactamases.
abstract: In the process of evolution, bacteria have acquired well-developed mechanisms of resistance to an extensive array of hostile substances. This time-tempered system of defense is so intricate and adaptable that contemporary medicine has been hard-pressed to maintain an advantage. In this article, the processes responsible for bacterial resistance to extended-spectrum cephalosporins are reviewed. Particular emphasis is placed on the extended-spectrum beta-lactamases that have emerged to provide bacteria with formidable resistance to modern drugs. Avoidance of this problem requires limitations on extended-spectrum cephalosporin usage. While carbapenems are clearly the treatment of choice for infections caused by these pathogens, empirical use of beta-lactam/beta-lactamase inhibitors such as piperacillin/tazobactam has been associated with reduction in the prevalence of cephalosporin resistance.
authors.affiliation: Medical Service III(w), Cleveland Veterans' Affairs Medical Center, 10701 East Blvd., Cleveland, OH 44106, USA.
authors.forename: L
authors.initials: L
authors.lastname: Rice
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology; D008826:Microbial Sensitivity Tests; D018440:beta-Lactam Resistance; D001618:beta-Lactamases; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases