Selection of Naturally Occurring Extended-Spectrum TEM β-Lactamase Variants by Fluctuating β-Lactam Pressure
Open Access
- 1 August 2000
- journal article
- research article
- Published by American Society for Microbiology in Antimicrobial Agents and Chemotherapy
- Vol. 44 (8) , 2182-2184
- https://doi.org/10.1128/aac.44.8.2182-2184.2000
Abstract
Despite the large number of in vitro mutations that increase resistance to extended-spectrum cephalosporins in TEM-type β-lactamases, only a small number occur in naturally occurring enzymes. In nature, and particularly in the hospital, bacteria that contain β-lactamases encounter simultaneous or consecutive selective pressure with different β-lactam molecules. All variants obtained by submitting an Escherichia coli strain that contains ablaTEM-1 gene to fluctuating challenge with both ceftazidime and amoxicillin contained only mutations previously detected in naturally occurring β-lactamases. Nevertheless, some variants obtained by ceftazidime challenge alone contained mutations never detected in naturally occurring TEM β-lactamases, suggesting that extended-spectrum TEM variants in hospital isolates result from fluctuating selective pressure with several β-lactams rather than selection with a single antibiotic.Keywords
This publication has 19 references indexed in Scilit:
- Evolution and Dissemination of β-Lactamases Accelerated by Generations of β-Lactam AntibioticsClinical Infectious Diseases, 1997
- An additional ionic bond suggested by molecular modelling of TEM-2 might induce a slight discrepancy between catalytic properties of TEM-1 and TEM-2 β-lactamasesFEMS Microbiology Letters, 1996
- Selection and Characterization of Amino Acid Substitutions at Residues 237-240 of TEM-1 β-Lactamase with Altered Substrate Specificity for Aztreonam and CeftazidimeJournal of Biological Chemistry, 1996
- A functional classification scheme for beta-lactamases and its correlation with molecular structureAntimicrobial Agents and Chemotherapy, 1995
- Single amino acid replacements at positions altered in naturally occurring extended-spectrum TEM beta-lactamasesAntimicrobial Agents and Chemotherapy, 1995
- Evolution of antibiotic resistance: several different amino acid substitutions in an active site loop alter the substrate profile of β‐lactamaseMolecular Microbiology, 1994
- Characterization of a new TEM-type beta-lactamase resistant to clavulanate, sulbactam, and tazobactam in a clinical isolate of Escherichia coliAntimicrobial Agents and Chemotherapy, 1993
- An efficient method for generating proteins with altered enzymatic properties: application to beta-lactamase.Proceedings of the National Academy of Sciences, 1989
- Classification of beta-lactamases: groups 1, 2a, 2b, and 2b'Antimicrobial Agents and Chemotherapy, 1989
- DNA sequencing with chain-terminating inhibitorsProceedings of the National Academy of Sciences, 1977