Genetic and biochemical characterization of OXA-1186, a novel OXA-198-type carbapenemase hydrolysing cephalosporins in Citrobacter freundii
Year: 2024
Type: article
Abstract: OBJECTIVES: This study described OXA-1186, a novel carbapenemase related to OXA-198 carbapenemase and produced by a clinical isolate of Citrobacter freundii. METHODS: WGS was used to characterize the resistome, virulome and plasmid types of the C. freundii 315C8 isolate and to reconstruct the blaOXA-1186-carrying plasmid. Disc diffusion and broth microdilution assays were used to determine MICs. The blaOXA-1186 gene was cloned into plasmid pTOPO and then transformed into Escherichia coli TOP10 or HB4. It was also cloned in pET41b and transformed into E. coli BL21 DE3 for protein purification. Steady-state kinetic parameters were determined on purified OXA-1186. RESULTS: C. freundii 315C8, belonging to ST8, was resistant to penicillins including temocillin and broad-spectrum cephalosporins and displayed reduced susceptibility to carbapenems. It was negative for one of the five main carbapenemases. WGS revealed that the blaOXA-1186 gene encoded a novel carbapenemase that shared 83% amino acid identity with OXA-198. The blaOXA-1186 gene was carried on an IncP6-type plasmid and was embedded within a class 1 integron. Cloning and expression in E. coli revealed that expression of the blaOXA-1186 gene conferred resistance to penicillins, cephalosporins and carbapenems, where it was associated with impaired outer membrane permeability. Kinetic parameters confirmed the hydrolysis of ceftazidime, cefepime and aztreonam, in addition to imipenem and meropenem. CONCLUSIONS: Here, we described a novel carbapenemase, OXA-1186, identified in C. freundii. Unlike OXA-198, OXA-1186 is able to hydrolyse broad-spectrum cephalosporins. This carbapenemase was carried on a broad-spectrum IncP6 plasmid identified in other Citrobacter species and non-fermenters.
DOI: 10.1093/jac/dkae339
Authors: Oceane Vanparis, Saoussen Oueslati, Delphine Girlich, Agnès B Jousset, Caroline Guyot, Anne Delaval, Thierry Naas, Laurent Dortet, Rémy A Bonnin
Institutions: Inserm, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique, Assistance Publique – Hôpitaux de Paris, Bicêtre Hospital, Groupe Hospitalier Intercommunal Le Raincy Montfermeil
Language: English
Subfield: Molecular Medicine
Domain: Life Sciences
Open Access status: bronze
Awards: G3010527862, Séquençage du génome entier et intelligence artificielle pour caratériser et diagnostiquer la résistance aux antibiotiques et la capacité d'échapper au traitement, New Antibiotics Tackling mUlti-Resistance by acting on Alternative bacteriaL tARgets in Synergy with mEmbrane-disruptiNg AntimicrobiaL peptides.
OpenAlex ID: W4402841171