OXA-372, a novel carbapenem-hydrolysing class D β-lactamase from a Citrobacter freundii isolated from a hospital wastewater plant
In: Journal of Antimicrobial Chemotherapy, 70 (10), 2749-2756 (2015, 2015
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Zugriff:
peer reviewed ; Objectives: The objective of this study was to characterize a novel class D carbapenemase, named OXA-372, identified in a carbapenem-resistant Citrobacter freundii strain (Cfr-FI-07) isolated from a hospital wastewater plant in central Italy. Methods: Cfr-FI-07 was isolated using a selective chromogenic medium for carbapenem-resistant Enterobacteriaceae. Carbapenemase production was confirmed by spectrophotometric assay. WGS was carried out using an Illumina MiSeq platform. The functional profile of OXA-372 was investigated by expression of the cloned gene in Escherichia coli and by analysis of kinetic parameters of the purified enzyme. Results: C. freundii Cfr-FI-07 produced carbapenemase activity, but tested negative for common carbapenemase genes. WGS confirmed the absence of known carbapenemase genes and revealed the presence of a novel class D b-lactamase (DBL) determinant, named blaOXA-372, encoding a protein distantly related to other DBLs. In E. coli, production of OXA-372 conferred resistance to penicillins, including temocillin, and reduced susceptibility to carbapenems, while susceptibility to expanded-spectrum cephalosporins was virtually unaffected. This substrate specificity was confirmed by kinetic characterization of the purified enzyme, which exhibited high catalytic efficiencies for carbapenems (kcat/KM values ≥0.22 s2-1.μM-1). The blaOXA-372 genewas associated with a genetic platform of original structure consisting of a Tn402/Tn5053 hybrid transposon derivative, named Tn6255, inserted into a TnPa38-like transposon, named Tn6256, located on an IncA/C-IncN plasmid of approximately 140 kb. Conclusions: OXA-372 is a novel class D carbapenemase, belonging to a new lineage of DBLs, encoded by a gene associated with mobile elements. Functional properties revealed similarities, but also some differences, compared with other class D carbapenemases. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights ...
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OXA-372, a novel carbapenem-hydrolysing class D β-lactamase from a Citrobacter freundii isolated from a hospital wastewater plant
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Autor/in / Beteiligte Person: | Antonelli, A. ; D'Andrea, M. M. ; Vaggelli, G. ; Docquier, Jean-Denis ; Rossolini, G. M. |
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Zeitschrift: | Journal of Antimicrobial Chemotherapy, 70 (10), 2749-2756 (2015, 2015 |
Veröffentlichung: | Oxford University Press, 2015 |
Medientyp: | academicJournal |
ISSN: | 0305-7453 (print) ; 1460-2091 (print) |
DOI: | 10.1093/jac/dkv181 |
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