New beta-lactamases: a paradigm for the rapid response of bacterial evolution in the clinical setting.
Production of beta-lactamases is one of the most common mechanisms of bacterial resistance to beta-lactam antibiotics. In the clinical setting, the introduction of new classes of beta-lactams has invariably been followed by the emergence of new beta-lactamases capable of degrading them, as a paradigmatic example of rapid bacterial evolution under a rapidly changing selective environment. The scope of this article is to provide an overview on the recent evolution of beta-lactamase-mediated resistance among bacterial pathogens. Focus is on the mechanisms of evolution and dissemination of enzymes of greater clinical impact, including the extended-spectrum beta-lactamases, the AmpC-type beta-lactamases and the carbapenemases, which are currently responsible for emerging resistance to the most recent and powerful beta-lactams (the expanded-spectrum cephalosporins and the carbapenems) among major Gram-negative pathogens such as Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter.
University of Siena, Department of Molecular Biology, Section of Microbiology, Policlinico Santa Maria alle Scotte, Siena, Italy. rossolini@unisi.it
Gian Maria
GM
Rossolini
Jean-Denis
JD
Docquier
D001419:Bacteria / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D019143:Evolution, Molecular; D009154:Mutation; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D015780:Carbapenems; D002511:Cephalosporins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases