Genetic, biochemical characterization and mutagenesis of the chromosomal class A β-lactamase of Raoultella (formerly Klebsiella) terrigena
| Autor: | V. Leflon-Guibout, Marie-Hélène Nicolas-Chanoine, E. Walckenaer, R. Bonnet, J. Delmas |
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| Rok vydání: | 2015 |
| Předmět: |
Molecular Sequence Data
Mutant Mutagenesis (molecular biology technique) beta-Lactams medicine.disease_cause Ceftazidime beta-Lactam Resistance beta-Lactamases Raoultella Bacterial Proteins Enterobacteriaceae Klebsiella terrigena Drug Resistance Multiple Bacterial Escherichia coli medicine Amino Acid Sequence Cloning Molecular Promoter Regions Genetic Sequence Homology Amino Acid biology General Medicine Chromosomes Bacterial biology.organism_classification Raoultella terrigena Raoultella ornithinolytica Molecular biology Raoultella planticola Anti-Bacterial Agents Amino Acid Substitution Genes Bacterial DNA Transposable Elements Mutagenesis Site-Directed Sequence Alignment human activities |
| Zdroj: | Pathologie Biologie. 63:158-163 |
| ISSN: | 0369-8114 |
| DOI: | 10.1016/j.patbio.2015.05.002 |
| Popis: | Background Chromosomal class A β-lactamases have been characterized in Raoultella ornithinolytica and Raoultella planticola. The purpose of this study was to characterize that of Raoultella terrigena. Materials and methods The blaTER-1 gene of R. terrigena strain ATCC33257T was cloned (pACter-1) and sequenced. It was then used to detect the bla gene of strains BM 85 01 095 and SB2796. The hypermutable Escherichia coli strain AB1157 mutS::Tn10 was transformed with pACter-1 and mutants growing on plates containing > 2 mg/L ceftazidime were studied. Notably, the impact of mutations only observed in the promoter region on β-lactam resistance was assessed by site-directed mutagenesis experiments. Results R. terrigena strains ATCC33257T and BM 85 01 095 had the same bla gene and deduced protein (TER-1) whereas there were 3 substitutions in those of strain SB2796 (TER-2). Class A β-lactamases TER showed 78%, 69.9% and 38.7% identity with PLA or ORN, TEM-1 and KOXY, respectively. Compared with TEM-1, TER-1 and TER-2 showed 2 particular substitutions, Leu75Pro and Glu240Asn demonstrated to be involved in the inherent β-lactam resistance profile of R. terrigena. TER-1 (pI of 7.6) had a high activity against penicillin G and a significantly low one against amoxicillin. Substitution G/T observed in the -35 region of the blaTER gene harbored by strains growing in the presence of ≥ 2 mg/L ceftazidime was shown to be responsible for this growth. Conclusion TER is a new class A β-lactamase belonging to functional group 2b. |
| Databáze: | OpenAIRE |
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