Evaluation of the Genmark ePlex\xae and QIAstat-Dx\xae respiratory pathogen panels in detecting bacterial targets in lower respiratory tract specimens

Suzanne A V Van Asten,Eric C J Claas,R Schuurman,Stefan A Boers,Jolanda D F De Groot

doi:10.1186/s12866-021-02289-w

Suzanne A V Van Asten, Eric C J Claas + Show 3 more

Open Access

https://doi.org/10.1186/s12866-021-02289-w

Copy DOI

Abstract

BackgroundThe ePlex® and QIAstat-Dx® respiratory pathogen panels detect multiple respiratory pathogens, mainly viruses but also Legionella pneumophila, Mycoplasma pneumoniae and Bordetella pertussis. The assays have been marketed for use in nasopharyngeal swab specimens. For diagnosing bacterial pneumonia, lower respiratory tract (LRT) specimens are indicated. Aim of this study was to evaluate the performance of these syndromic panels for these three bacterial targets in samples from the LRT. Fifty-six specimens were collected from our repositories, five negative samples and fifty-one samples which had been previously tested positive with the routine diagnostic real-time PCR assays for Legionella spp. (N = 20), Bordetella spp. (N = 16) or M. pneumoniae (N = 15).ResultsThe QIAstat-Dx Respiratory Panel V2 (RP) assay detected all of the L. pneumophila and B. pertussis positive samples but only 11/15 (73.3 %) of the M. pneumoniae targets. The ePlex Respiratory Pathogen Panel (RPP) assay detected 10/14 (71.4 %) of the L. pneumophila targets, 8/12 (66.7 %) of the B. pertussis positive samples and 13/15 (86.7 %) of the M. pneumoniae targets.ConclusionsNo false-positive results were reported for all three bacterial pathogens by both assays. The clinical performance of both assays depended highly on the bacterial load in the sample and the type of specimen under investigation.

Highlights

The ePlex® and QIAstat-Dx® respiratory pathogen panels detect multiple respiratory pathogens, mainly viruses and Legionella pneumophila, Mycoplasma pneumoniae and Bordetella pertussis
Of the 56 samples analyzed with the ePlex® Respiratory Pathogen Panel (RPP) assay one result was invalid after repeat testing, a mucopurulent sputum sample originally containing a very low level of L. pneumophila DNA (CT 38.5) that tested negative with the QIAstat-Dx® Respiratory Panel V2 (RP) assay
In one of the nasopharyngeal swab samples only the Bordetella IS1001 target was detected by the LDT assay, indicating that this sample was positive for B. parapertussis

Summary

Introduction

The ePlex® and QIAstat-Dx® respiratory pathogen panels detect multiple respiratory pathogens, mainly viruses and Legionella pneumophila, Mycoplasma pneumoniae and Bordetella pertussis. There is substantial progress in the development of syndromic testing platforms for respiratory infections, gastroenteritis and even neurological infections [2] These assays are able to rapidly detect multiple pathogens associated to clinical syndromes, including viruses, bacteria and parasites [2,3,4]. In a recent clinical application study, the assay resulted in improved prescription of antimicrobial therapy, a reduction in isolation days of admitted patients, and detection of pathogens that were not requested to investigate by the clinician [7]. Another rapid cartridge-based assay, the QIAstat-Dx® RP assay (Qiagen®) has become available for detection of 21 respiratory pathogens. The QIAstat-Dx® RP assay provides CT values and a semi-quantitative indication of the pathogen load within the samples

Objectives

Methods

Results

Discussion

Conclusion