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E240V substitution increases catalytic efficiency toward ceftazidime in a new natural TEM-type extended-spectrum beta-lactamase, TEM-149, from Enterobacter aerogenes and Serratia marcescens clinical isolates.
- Source :
-
Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2008 Mar; Vol. 52 (3), pp. 915-9. Date of Electronic Publication: 2007 Dec 26. - Publication Year :
- 2008
-
Abstract
- The aim of this study was to characterize a novel extended-spectrum beta-lactamase that belongs to the TEM family, the TEM-149 enzyme, and that was isolated from the urine of two hospitalized patients from different hospitals in southern Italy. The peculiarity of this enzyme was the finding of a valine residue at position 240. The array of amino acid substitutions found in TEM-149 was as follows: E104K, R164S, M182T, and E240V. A reversion of a threonine residue at position 182 was also performed to create a new mutant, TEM-149 T182M, in order to assess the contribution of this substitution on the kinetic profile and the stability of TEM-149. The bla TEM-149 and bla TEM-149/T182M genes were cloned into pBC-SK, and the corresponding enzymes were purified from recombinant Escherichia coli HB101 by the same procedure. Both enzymes hydrolyzed all beta-lactams tested, with a preference for ceftazidime, which was found to be the best substrate. By comparison of the kinetic parameters of the TEM-149 and the TEM-149 T182M enzymes, a reduction of the catalytic efficiency for the TEM-149 T182M mutant was observed against all substrates tested except benzylpenicillin, cefotaxime, and aztreonam. Tazobactam, clavulanic acid, and sulbactam were good inhibitors of the TEM-149 beta-lactamase.
- Subjects :
- Catalysis
Enterobacter aerogenes drug effects
Enterobacter aerogenes genetics
Enterobacter aerogenes isolation & purification
Humans
Kinetics
Microbial Sensitivity Tests
Models, Molecular
Molecular Sequence Data
Sequence Analysis, DNA
Serratia marcescens drug effects
Serratia marcescens genetics
Serratia marcescens isolation & purification
Structure-Activity Relationship
Substrate Specificity
beta-Lactamases chemistry
beta-Lactamases metabolism
beta-Lactams pharmacology
Amino Acid Substitution
Anti-Bacterial Agents metabolism
Ceftazidime metabolism
Enterobacter aerogenes enzymology
Serratia marcescens enzymology
beta-Lactamases genetics
Subjects
Details
- Language :
- English
- ISSN :
- 0066-4804
- Volume :
- 52
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Antimicrobial agents and chemotherapy
- Publication Type :
- Academic Journal
- Accession number :
- 18160520
- Full Text :
- https://doi.org/10.1128/AAC.01028-07