Pérez-Llarena, Francisco J.Kerff, FrédéricZamorano, LauraFernández-López, María del CarmenNúñez, María LuzMiró, ElisendaOliver, AntonioNavarro, FerránBou, Germán2026-10-192026-10-192013-09-13Pérez-Llarena FJ, Kerff F, Zamorano L, Fernández MC, Nuñez ML, Miró E, Oliver A, Navarro F, Bou G. Characterization of the new AmpC β-lactamase FOX-8 reveals a single mutation, Phe313Leu, located in the R2 loop that affects ceftazidime hydrolysis. Antimicrob Agents Chemother. 2013 Oct;57(10):5158-61.0066-4804https://hdl.handle.net/2183/49832Brief report[Abstract] 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 and alters the phenotype of E. coli strains carrying this variant.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Bacterial ProteinsCeftazidimeEscherichia colibeta-Lactamasesjournal articleopen access10.1128/aac.00818-13