Genetic and biochemical characterization of OXA-1054, a carbapenem-hydrolyzing class D β-lactamase conferring broad-spectrum β-lactam resistance in Pseudomonas aeruginosa
Year: 2026
Type: article
Abstract: ABSTRACT We aimed to characterize OXA-1054, a novel carbapenem-hydrolyzing class D β-lactamase (CHDL) detected in a multidrug-resistant Pseudomonas aeruginosa clinical isolate. Antimicrobial susceptibility was determined by broth microdilution, and carbapenemase activity was confirmed by hydrolysis assays. Whole-genome sequencing via Illumina and PacBio platforms enabled comprehensive analysis of the resistome and plasmid architecture. The bla OXA-1054 gene was cloned in parallel with bla OXA-48 and bla OXA-198 into the pUCP24 plasmid. β-Lactamases were produced in P. aeruginosa PAO1 for comparative evaluation of the phenotypic impact of each. OXA-48, OXA-198, and OXA-1054 β-lactamases were purified and further subjected to steady-state kinetic analysis, and 50% inhibitory activity of β-lactamase inhibitors was determined. The clinical P. aeruginosa isolate ARGA00461 showed resistance to carbapenems and most β-lactam/β-lactamase inhibitor combinations and tested positive in carbapenem hydrolysis assays. Genomic analysis revealed that the P. aeruginosa isolate ARGA00461 carried a gene coding for a previously uncharacterized CHDL, designated OXA-1054, which is closely related to the OXA-372 enzyme of environmental origin. The bla OXA-1054 gene was located in a small (≈5 kbp) non-conjugative plasmid coexisting with a conjugative IncP plasmid, which likely facilitated its mobilization. Production of OXA-1054 in P. aeruginosa PAO1 conferred a broader spectrum of β-lactam resistance than other CHDLs. Enzyme kinetics confirmed carbapenem hydrolysis with catalytic efficiency comparable to OXA-48 and revealed higher affinity for cefepime compared to OXA-48 and OXA-198. Among the inhibitors tested, only avibactam demonstrated relevant inhibitory activity. OXA-1054 mediates broad-spectrum β-lactam resistance in P. aeruginosa , including carbapenems and β-lactam/β-lactamase inhibitor combinations.
DOI: 10.1128/aac.01805-25
Institutions: Universidade da Coruña, Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red, Complexo Hospitalario Universitario A Coruña, Servicio Gallego de Salud, Instituto de Investigación Biomédica de A Coruña, Centro de Investigación Biomédica en Red Enfermedades Infecciosas, Consejo Superior de Investigaciones Científicas, Hospital Universitario Virgen Macarena, Instituto de Biomedicina de Sevilla, Universidad de Sevilla, Health Research Institute of the Balearic Islands, Hospital Universitario Son Espases, CHU Dinant Godinne UCL Namur
Language: English
Subfield: Molecular Medicine
Domain: Life Sciences
Open Access status: diamond
Awards: G1670048366, G2427436359, G2845714328, G2857904082, Vacunas auxótrofas orales para la erradicación de bacterias intestinales: colonización intestinal por Klebsiella pneumoniae multirresistente como modelo, G306770859, G5195802681, Optimización del diagnóstico, tratamiento y control de las infecciones por Pseudomonas aeruginosa a través de la monitorización de la dinámica del resistoma a escala de paciente y de nación completa., G5789885583, G5921404938, Inhibidores de carbapenemasas: actividad frente a Enterobacterales productores de carbapenemasas, mecanismos e impacto en la evolución de la resistencia antimicrobiana (PROTECT), G6171360028, Vacunas versátiles basadas en ARN para combatir las infecciones causadas por cepas multirresistentes de Pseudomonas aeruginosa, G787257, G8725042212
OpenAlex ID: W7162763137