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Characterization of the new AmpC ?-lactamase FOX-8 reveals a single mutation, Phe313Leu, located in the R2 loop that affects ceftazidime hydrolysis.

ABSTRACT: A novel class C ?-lactamase (FOX-8) was isolated from a clinical strain of Escherichia coli. The FOX-8 enzyme possessed a unique substitution (Phe313Leu) compared to FOX-3. Isogenic E. coli strains carrying FOX-8 showed an 8-fold reduction in resistance to ceftazidime relative to FOX-3. In a kinetic analysis, FOX-8 displayed a 33-fold reduction in kcat/Km for ceftazidime compared to FOX-3. In the FOX family of ?-lactamases, the Phe313 residue located in the R2 loop affects ceftazidime hydrolysis and alters the phenotype of E. coli strains carrying this variant.

SUBMITTER: Perez-Llarena FJ

PROVIDER: S-EPMC3811397 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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Characterization of the new AmpC β-lactamase FOX-8 reveals a single mutation, Phe313Leu, located in the R2 loop that affects ceftazidime hydrolysis.

Pérez-Llarena Francisco José FJ Kerff Frédéric F Zamorano Laura L Fernández María Carmen MC Nuñez Maria Luz ML Miró Elisenda E Oliver Antonio A Navarro Ferran F Bou Germán G

Antimicrobial agents and chemotherapy 20130722 10

A novel class C β-lactamase (FOX-8) was isolated from a clinical strain of Escherichia coli. The FOX-8 enzyme possessed a unique substitution (Phe313Leu) compared to FOX-3. Isogenic E. coli strains carrying FOX-8 showed an 8-fold reduction in resistance to ceftazidime relative to FOX-3. In a kinetic analysis, FOX-8 displayed a 33-fold reduction in kcat/Km for ceftazidime compared to FOX-3. In the FOX family of β-lactamases, the Phe313 residue located in the R2 loop affects ceftazidime hydrolysis ...[more]

PMID: 23877692

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