Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship

Ceftazidime–avibactam (CZA) is a potent broad-spectrum drug combination covering extended-spectrum β-lactamases, AmpC, and carbapenemases of class A and D, OXA-48-type producers. Rapid antimicrobial susceptibility testing is crucial for the timely de-escalation/escalation of therapy. We evaluate CZA...

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Main Authors: Inês Martins-Oliveira, Blanca Pérez-Viso, Rosário Gomes, David Abreu, Ana Silva-Dias, Rafael Cantón, Cidália Pina-Vaz
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/2/414
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author Inês Martins-Oliveira
Blanca Pérez-Viso
Rosário Gomes
David Abreu
Ana Silva-Dias
Rafael Cantón
Cidália Pina-Vaz
author_facet Inês Martins-Oliveira
Blanca Pérez-Viso
Rosário Gomes
David Abreu
Ana Silva-Dias
Rafael Cantón
Cidália Pina-Vaz
author_sort Inês Martins-Oliveira
collection DOAJ
description Ceftazidime–avibactam (CZA) is a potent broad-spectrum drug combination covering extended-spectrum β-lactamases, AmpC, and carbapenemases of class A and D, OXA-48-type producers. Rapid antimicrobial susceptibility testing is crucial for the timely de-escalation/escalation of therapy. We evaluate CZA susceptibility using the CE-IVD FASTgramneg kit (FASTinov<sup>®</sup>), a ground-breaking 2 h assay, based on flow cytometry technology for antimicrobial susceptibility testing. The assay involved rapid bacterial extraction and purification from positive blood cultures (PBCs), followed by a 1 h 37 °C incubation and flow cytometry analysis (Cytoflex, Beckman-Coulter). The susceptibility report was generated using a proprietary software and interpreted using EUCAST and CLSI 2024 criteria. Sensitivity and specificity were calculated against a reference standardized method (disk diffusion) according to ISO20776-2:2021. Overall, 135 Enterobacterales and 73 <i>Pseudomonas aeruginosa</i> isolates were studied. Thirty-four isolates were resistant to CZA, including six <i>P. aeruginosa</i> and 28 Enterobacterales (24 metallo-beta-lactamase producers, three KPC variants, and one co-producing KPC+NDM). Sensitivity and specificity reached 100% when using EUCAST and CLSI criteria compared with the reference method. The FASTinov ultra-rapid susceptibility assay for CZA demonstrated excellent results, potentially enabling de-escalation/escalation even before the second dose. Combining the speed of a molecular assay with the comprehensive information of a phenotypic test offers valuable insights for treatment decisions.
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spelling doaj-art-1df8ad9bbf8d4e5ead9a6821fb7217752025-08-20T02:44:47ZengMDPI AGMicroorganisms2076-26072025-02-0113241410.3390/microorganisms13020414Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial StewardshipInês Martins-Oliveira0Blanca Pérez-Viso1Rosário Gomes2David Abreu3Ana Silva-Dias4Rafael Cantón5Cidália Pina-Vaz6FASTinov, S.A., 4200-135 Porto, PortugalServicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, SpainFASTinov, S.A., 4200-135 Porto, PortugalFASTinov, S.A., 4200-135 Porto, PortugalFASTinov, S.A., 4200-135 Porto, PortugalServicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, SpainFASTinov, S.A., 4200-135 Porto, PortugalCeftazidime–avibactam (CZA) is a potent broad-spectrum drug combination covering extended-spectrum β-lactamases, AmpC, and carbapenemases of class A and D, OXA-48-type producers. Rapid antimicrobial susceptibility testing is crucial for the timely de-escalation/escalation of therapy. We evaluate CZA susceptibility using the CE-IVD FASTgramneg kit (FASTinov<sup>®</sup>), a ground-breaking 2 h assay, based on flow cytometry technology for antimicrobial susceptibility testing. The assay involved rapid bacterial extraction and purification from positive blood cultures (PBCs), followed by a 1 h 37 °C incubation and flow cytometry analysis (Cytoflex, Beckman-Coulter). The susceptibility report was generated using a proprietary software and interpreted using EUCAST and CLSI 2024 criteria. Sensitivity and specificity were calculated against a reference standardized method (disk diffusion) according to ISO20776-2:2021. Overall, 135 Enterobacterales and 73 <i>Pseudomonas aeruginosa</i> isolates were studied. Thirty-four isolates were resistant to CZA, including six <i>P. aeruginosa</i> and 28 Enterobacterales (24 metallo-beta-lactamase producers, three KPC variants, and one co-producing KPC+NDM). Sensitivity and specificity reached 100% when using EUCAST and CLSI criteria compared with the reference method. The FASTinov ultra-rapid susceptibility assay for CZA demonstrated excellent results, potentially enabling de-escalation/escalation even before the second dose. Combining the speed of a molecular assay with the comprehensive information of a phenotypic test offers valuable insights for treatment decisions.https://www.mdpi.com/2076-2607/13/2/414antimicrobial susceptibility testingceftazidime–avibactamGram-negative bacteriarapid diagnosticsflow cytometryantibiotic escalation/de-escalation
spellingShingle Inês Martins-Oliveira
Blanca Pérez-Viso
Rosário Gomes
David Abreu
Ana Silva-Dias
Rafael Cantón
Cidália Pina-Vaz
Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship
Microorganisms
antimicrobial susceptibility testing
ceftazidime–avibactam
Gram-negative bacteria
rapid diagnostics
flow cytometry
antibiotic escalation/de-escalation
title Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship
title_full Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship
title_fullStr Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship
title_full_unstemmed Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship
title_short Phenotypic Ultra-Rapid Antimicrobial Susceptibility Testing for Ceftazidime–Avibactam: In Support of Antimicrobial Stewardship
title_sort phenotypic ultra rapid antimicrobial susceptibility testing for ceftazidime avibactam in support of antimicrobial stewardship
topic antimicrobial susceptibility testing
ceftazidime–avibactam
Gram-negative bacteria
rapid diagnostics
flow cytometry
antibiotic escalation/de-escalation
url https://www.mdpi.com/2076-2607/13/2/414
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