Oueslati, Saoussen Nordmann, Patrice Poirel, Laurent 2015 Objectives Carbapenem-hydrolysing class D β-lactamases of the OXA-48 type are increasingly reported from Enterobacteriaceae. β-Lactamase OXA-48 hydrolyses penicillins very efficiently, but carbapenems only weakly and spares broad-spectrum cephalosporins. Recently, diverse OXA-48-like β-lactamases have been identified worldwide (OXA-162, OXA-181, OXA-163, OXA-204 and OXA-232). They differ by few amino acid substitutions or by amino acid deletions. Methods blaOXA-48, blaOXA-162, blaOXA-163, blaOXA-181, blaOXA-204 and blaOXA-232 were cloned into the same expression vector and expressed in the same Escherichia coli background. Kinetic studies were performed with enzymes purified by ion-exchange chromatography. Determination of hydrolytic activities was performed by UV spectrophotometry. MICs were determined for all recombinant strains, using as background either the WT E. coli TOP10 strain or a porin-deficient E. coli strain. Results Kinetic studies showed that OXA-162 and OXA-204 shared the same hydrolytic properties as OXA-48. On the other hand, OXA-181 possessed a higher ability to hydrolyse carbapenems, while OXA-232 hydrolysed those substrates less efficiently. In contrast to the other OXA-48-like β-lactamases, OXA-163 hydrolysed broad-spectrum cephalosporins very efficiently, but did not possess significant carbapenemase activity. Although several of these OXA-48-like enzymes possess low activity against carbapenems, MICs of carbapenems were significantly elevated when determined for strains possessing permeability defects. Conclusions A detailed comparative analysis of the kinetic properties of the OXA-48-like β-lactamases is provided here. It clarifies the respective features of each OXA-48-like variant and their respective impacts in terms of carbapenem resistance application/pdf https://sonar.ch/global/documents/305737 eng info:eu-repo/semantics/altIdentifier/doi/10.1093/jac/dku524 info:eu-repo/semantics/openAccess License undefined, © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com Journal of Antimicrobial Chemotherapy. - Oxford University Press. - 2015, vol. 70, no. 4, p. 1059-1063 info:eu-repo/classification/udc/61 Heterogeneous hydrolytic features for OXA-48-like β-lactamases http://purl.org/coar/resource_type/c_6501