Carbapenemase detection testing in the era of ceftazidime/avibactam-resistant KPC-producing Enterobacterales: A 2-year experience.

Autor: Bianco G; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy. Electronic address: gabriele.bianco@unito.it., Boattini M; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Iannaccone M; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Bondi A; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Ghibaudo D; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Zanotto E; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Peradotto M; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Cavallo R; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy., Costa C; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88/90, 10126 Turin, Italy.
Jazyk: angličtina
Zdroj: Journal of global antimicrobial resistance [J Glob Antimicrob Resist] 2021 Mar; Vol. 24, pp. 411-414. Date of Electronic Publication: 2021 Feb 20.
DOI: 10.1016/j.jgar.2021.02.008
Abstrakt: Objectives: The aim of this study was to investigate the prevalence of ceftazidime/avibactam (CZA) resistance among carbapenemase-producing Enterobacterales (CPE) blood culture isolates as well as the performance of the main carbapenemase phenotypic detection methods to identify KPC variants associated with CZA resistance.
Methods: Non-duplicate CPE strains isolated from blood cultures during 2018-2020 were tested for antimicrobial susceptibility. Molecular testing was used to identify carbapenemase-producers. Strains harbouring bla KPC and with a CZA minimum inhibitory concentration (MIC) ≥8 mg/L were investigated by sequencing. Subsequentially, five phenotypic carbapenemase detection methods were evaluated on these strains, namely the modified carbapenem inactivation method (mCIM), Rapidec® Carba NP, the disk diffusion synergy test, NG-Test CARBA® 5 and RESIST-5 O.O.K.N.V.
Results: Overall, the CZA resistance rate was high (13.7%) and remained relevant (5.9%) excluding metallo-β-lactamases-producers. All isolates harbouringbla KPC mutants (n = 8) were associated with reduced carbapenem MICs and negative results by all detection methods based on revelation of enzyme activity. Lateral flow immunoassays failed to detect KPC-31 (n = 4) and KPC-33 (n = 2) but correctly identified KPC-14 (n = 2). Conversely, isolates harbouring wild-type KPC genes (n = 3) were associated with high-level CZA resistance and carbapenem resistance and tested positive by all of the evaluated methods.
Conclusion: In the era of CZA-based therapies, molecular bla KPC identification followed by a carbapenem hydrolysis-based phenotypic assay could be the most reasonable diagnostic algorithm to detect all KPC-producers and to identify mutants associated with impaired carbapenemase activity and CZA resistance.
(Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
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