Identification of a CTX-M-255 β-lactamase containing a G239S substitution selectively conferring resistance to penicillin/β-lactamase inhibitor combinations.

Autor:	Andreasen MR; Department of Science and Environment, Roskilde University, Roskilde, Denmark.; Department of Clinical Microbiology, Copenhagen University Hospital-Amager and Hvidovre, Copenhagen, Denmark., Rick T; Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark., Alexandersen NR; Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark., Hansen KH; Department of Clinical Microbiology, Copenhagen University Hospital-Amager and Hvidovre, Copenhagen, Denmark.; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark., Pedersen MS; Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark., Warweitzky JK; Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany.; Twincore, Centre for Experimental and Clinical Infection Research, A Joint Venture of the Helmholtz Centre for Infection Research and the Hannover Medical School, Hannover, Germany., Botelho CM; Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany.; Twincore, Centre for Experimental and Clinical Infection Research, A Joint Venture of the Helmholtz Centre for Infection Research and the Hannover Medical School, Hannover, Germany., Häussler S; Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.; Department Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany.; Twincore, Centre for Experimental and Clinical Infection Research, A Joint Venture of the Helmholtz Centre for Infection Research and the Hannover Medical School, Hannover, Germany., Jelsbak L; Department of Science and Environment, Roskilde University, Roskilde, Denmark., Schønning K; Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Jazyk:	angličtina
Zdroj:	The Journal of antimicrobial chemotherapy [J Antimicrob Chemother] 2024 Apr 02; Vol. 79 (4), pp. 810-814.
DOI:	10.1093/jac/dkae033
Abstrakt:	Objectives: An Escherichia coli isolate, WGS1363, showed resistance to piperacillin/tazobactam but susceptibility to cephalosporins and contained a previously unrecognized β-lactamase, CTX-M-255, as the only acquired β-lactamase. CTX-M-255 was identical to CTX-M-27 except for a G239S substitution. Here, we characterize the hydrolytic spectrum of CTX-M-255 and a previously reported β-lactamase, CTX-M-178, also containing a G239S substitution and compare it to their respective parental enzymes, CTX-M-27 and CTX-M-15. Methods: All β-lactamase genes were expressed in E. coli TOP10 and MICs to representative β-lactam-antibiotics were determined. Furthermore, blaCTX-M-15,  blaCTX-M-27, blaCTX-M-178 and blaCTX-M-255 with C-terminal His-tag fusions were affinity purified for enzyme kinetic assays determining Michaelis-Menten kinetic parameters against representative β-lactam-antibiotics and IC50s of clavulanate, sulbactam, tazobactam and avibactam. Results: TOP10-transformants expressing blaCTX-M-178 and blaCTX-M-255 showed resistance to penicillin/β-lactamase combinations and susceptibility to cephalothin and cefotaxime in contrast to transformants expressing blaCTX-M-15 and blaCTX-M-27. Determination of enzyme kinetic parameters showed that CTX-M-178 and CTX-M-255 both lacked hydrolytic activity against cephalosporins and showed impaired hydrolytic efficiency against penicillin antibiotics compared to their parental enzymes. Both enzymes appeared more active against piperacillin compared to benzylpenicillin and ampicillin. Compared to their parental enzymes, IC50s of β-lactamase-inhibitors were increased more than 1000-fold for CTX-M-178 and CTX-M-255. Conclusions: CTX-M-178 and CTX-M-255, both containing a G239S substitution, conferred resistance to piperacillin/tazobactam and may be characterized as inhibitor-resistant CTX-M β-lactamases. Inhibitor resistance was accompanied by loss of activity against cephalosporins and monobactams. These findings add to the necessary knowledge base for predicting antibiotic susceptibility from genotypic data. (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
Databáze:	MEDLINE
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