Dataset Information

Comparison of GeneXpert MRSA/SA ETA assay with semi-quantitative and quantitative cultures and nuc gene-based qPCR for detection of Staphylococcus aureus in endotracheal aspirate samples.

ABSTRACT:

Introduction

Staphylococcus aureus (S. aureus) is a common cause of ventilator-associated pneumonia. Rapid and accurate detection of lower respiratory tract colonization and/or infection with S. aureus may inform targeted preventive and therapeutic strategies. To investigate this, we compared semi-quantitative (SQ)-culture results from 79 endotracheal aspirates (ETA) collected from mechanically-ventilated patients, to two culture and two non-culture-based methods for detection of S. aureus.

Methods

ETA analyzed by routine SQ-culture on blood and colistin-nalidixic-acid agar was compared to: (i) quantitative (Q-) culture on chromogenic COLOREX™ Staph aureus; (ii) enrichment in brain-heart-infusion broth followed by plating on blood agar and COLOREX™; (iii) nuc-based TaqMan qPCR, and (iv) GeneXpert MRSA/SA ETA assay.

Results

Of the 79 ETA samples analyzed by SQ-culture, 39 samples were positive, and 40 negative for S. aureus. Two samples negative for S. aureus by SQ-culture were, however, S. aureus-positive by the other four methods and were considered positive. Appending these two samples as positive in the SQ-culture results, sensitivities-specificities for Q-culture, enrichment-culture, TaqMan qPCR and GeneXpert were 100-95, 100-92, 100-53% and 100%?-?100, respectively. The lower specificities of Q-culture, enrichment-culture, and TaqMan qPCR was because of their higher sensitivities, although TaqMan qPCR also detected S. aureus-specific extracellular DNA.

Conclusion

This first evaluation of the GeneXpert MRSA/SA ETA assay with ETA samples found it to be highly sensitive, specific, user-friendly (hands-on time ~?5?min.), and rapid (~?66?min. assay time). Where this equipment is not available, we recommend implementing more sensitive culture-based methods for improved S. aureus detection in ETA samples.

SUBMITTER: Coppens J

PROVIDER: S-EPMC6321727 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Comparison of GeneXpert MRSA/SA ETA assay with semi-quantitative and quantitative cultures and <i>nuc</i> gene-based qPCR for detection of <i>Staphylococcus aureus</i> in endotracheal aspirate samples.

Coppens Jasmine J Van Heirstraeten Liesbet L Ruzin Alexey A Yu Li L Timbermont Leen L Lammens Christine C Matheeussen Veerle V Matheeussen Veerle V McCarthy Michael M Jorens Philippe P Ieven Margareta M Kumar-Singh Samir S Goossens Herman H Malhotra-Kumar Surbhi S

Antimicrobial resistance and infection control 20190105

<h4>Introduction</h4><i>Staphylococcus aureus (S. aureus)</i> is a common cause of ventilator-associated pneumonia. Rapid and accurate detection of lower respiratory tract colonization and/or infection with <i>S. aureus</i> may inform targeted preventive and therapeutic strategies. To investigate this, we compared semi-quantitative (SQ)-culture results from 79 endotracheal aspirates (ETA) collected from mechanically-ventilated patients, to two culture and two non-culture-based methods for detect ...[more]

PMID: 30627428

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