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Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases

There is a critical need for rapid diagnostic methods for multidrug-resistant (MDR) pathogens in patients with a suspicion of ventilator-associated pneumonia (VAP). The Xpert Carba-R detects 5 targets for carbapenemase-producing organisms (bla(KPC), bla(NDM), bla(VIM), bla(OXA-48), and bla(IMP-1))....

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Autores principales: Burillo, Almudena, Marín, Mercedes, Cercenado, Emilia, Ruiz-Carrascoso, Guillermo, Pérez-Granda, María Jesús, Oteo, Jesús, Bouza, Emilio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5161504/
https://www.ncbi.nlm.nih.gov/pubmed/27992521
http://dx.doi.org/10.1371/journal.pone.0168473
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author Burillo, Almudena
Marín, Mercedes
Cercenado, Emilia
Ruiz-Carrascoso, Guillermo
Pérez-Granda, María Jesús
Oteo, Jesús
Bouza, Emilio
author_facet Burillo, Almudena
Marín, Mercedes
Cercenado, Emilia
Ruiz-Carrascoso, Guillermo
Pérez-Granda, María Jesús
Oteo, Jesús
Bouza, Emilio
author_sort Burillo, Almudena
collection PubMed
description There is a critical need for rapid diagnostic methods for multidrug-resistant (MDR) pathogens in patients with a suspicion of ventilator-associated pneumonia (VAP). The Xpert Carba-R detects 5 targets for carbapenemase-producing organisms (bla(KPC), bla(NDM), bla(VIM), bla(OXA-48), and bla(IMP-1)). Our objective was to evaluate the performance of this assay directly on bronchial aspirates and to correlate the cycle number for a positive result (Ct) with the bacterial count. Bronchial aspirates from patients with a suspicion of VAP were spiked with a dilution of 1 of 4 MDR organisms carrying the resistance genes detected by the test prepared to a final concentration of 10(2)−10(5) cfu/mL. We used a ROC curve and provided areas under the curve (AUC) with their 95% confidence intervals (CI). A point of maximum sensitivity (Se) and specificity (Sp) was derived and validity indices were calculated. One hundred contrived tests were performed. Se and Sp were 100% for all bacterial counts. A positive sample with a Ct ≤24.7 corresponded to a count ≥10(5) cfu/mL; if the Ct was within the range >24.7-≤26.9, this corresponded to a count ≥10(4) cfu/mL. When the Ct was >26.9, this corresponded to a count <10(4) cfu/mL. The Xpert Carba-R detects carbapenemase-producing organisms directly in contrived bronchial aspirates. Still, an important issue to consider is that the number of gene copies may vary according to many factors in vivo. If confirmed in further studies, the strong correlation observed between Ct values and the results of semiquantitative cultures suggests this test could serve to differentiate between infection and colonization in routine clinical practice.
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spelling pubmed-51615042017-01-04 Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases Burillo, Almudena Marín, Mercedes Cercenado, Emilia Ruiz-Carrascoso, Guillermo Pérez-Granda, María Jesús Oteo, Jesús Bouza, Emilio PLoS One Research Article There is a critical need for rapid diagnostic methods for multidrug-resistant (MDR) pathogens in patients with a suspicion of ventilator-associated pneumonia (VAP). The Xpert Carba-R detects 5 targets for carbapenemase-producing organisms (bla(KPC), bla(NDM), bla(VIM), bla(OXA-48), and bla(IMP-1)). Our objective was to evaluate the performance of this assay directly on bronchial aspirates and to correlate the cycle number for a positive result (Ct) with the bacterial count. Bronchial aspirates from patients with a suspicion of VAP were spiked with a dilution of 1 of 4 MDR organisms carrying the resistance genes detected by the test prepared to a final concentration of 10(2)−10(5) cfu/mL. We used a ROC curve and provided areas under the curve (AUC) with their 95% confidence intervals (CI). A point of maximum sensitivity (Se) and specificity (Sp) was derived and validity indices were calculated. One hundred contrived tests were performed. Se and Sp were 100% for all bacterial counts. A positive sample with a Ct ≤24.7 corresponded to a count ≥10(5) cfu/mL; if the Ct was within the range >24.7-≤26.9, this corresponded to a count ≥10(4) cfu/mL. When the Ct was >26.9, this corresponded to a count <10(4) cfu/mL. The Xpert Carba-R detects carbapenemase-producing organisms directly in contrived bronchial aspirates. Still, an important issue to consider is that the number of gene copies may vary according to many factors in vivo. If confirmed in further studies, the strong correlation observed between Ct values and the results of semiquantitative cultures suggests this test could serve to differentiate between infection and colonization in routine clinical practice. Public Library of Science 2016-12-16 /pmc/articles/PMC5161504/ /pubmed/27992521 http://dx.doi.org/10.1371/journal.pone.0168473 Text en © 2016 Burillo et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Burillo, Almudena
Marín, Mercedes
Cercenado, Emilia
Ruiz-Carrascoso, Guillermo
Pérez-Granda, María Jesús
Oteo, Jesús
Bouza, Emilio
Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases
title Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases
title_full Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases
title_fullStr Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases
title_full_unstemmed Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases
title_short Evaluation of the Xpert Carba-R (Cepheid) Assay Using Contrived Bronchial Specimens from Patients with Suspicion of Ventilator-Associated Pneumonia for the Detection of Prevalent Carbapenemases
title_sort evaluation of the xpert carba-r (cepheid) assay using contrived bronchial specimens from patients with suspicion of ventilator-associated pneumonia for the detection of prevalent carbapenemases
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5161504/
https://www.ncbi.nlm.nih.gov/pubmed/27992521
http://dx.doi.org/10.1371/journal.pone.0168473
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