One time quantitative PCR detection of Pseudomonas aeruginosa to discriminate intermittent from chronic infection in cystic fibrosis

Sébastien Boutin; Michael Weitnauer; Selina Hassel; Simon Y Graeber; Mirjam Stahl; A Susanne Dittrich; Marcus A Mall; Alexander H Dalpke

doi:10.1016/j.jcf.2017.12.007

One time quantitative PCR detection of Pseudomonas aeruginosa to discriminate intermittent from chronic infection in cystic fibrosis

J Cyst Fibros. 2018 May;17(3):348-355. doi: 10.1016/j.jcf.2017.12.007. Epub 2018 Jan 12.

Authors

Sébastien Boutin¹, Michael Weitnauer², Selina Hassel¹, Simon Y Graeber³, Mirjam Stahl³, A Susanne Dittrich⁴, Marcus A Mall³, Alexander H Dalpke⁵

Affiliations

¹ Department of Infectious Disease, Medical Microbiology and Hygiene, University Hospital Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany.
² Department of Infectious Disease, Medical Microbiology and Hygiene, University Hospital Heidelberg, Germany.
³ Division of Pediatric Pulmonology and Allergy and Cystic Fibrosis Center, Department of Pediatrics, University of Heidelberg, Heidelberg, Germany; Department of Translational Pulmonology, University of Heidelberg, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany.
⁴ Department of Translational Pulmonology, University of Heidelberg, Heidelberg, Germany; Department of Pneumology and Critical Care Medicine, Thoraxklinik at the University Hospital Heidelberg, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany.
⁵ Department of Infectious Disease, Medical Microbiology and Hygiene, University Hospital Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany. Electronic address: alexander.dalpke@med.uni-heidelberg.de.

PMID: 29336943
DOI: 10.1016/j.jcf.2017.12.007

Abstract

Background: Chronic airway infection with Pseudomonas aeruginosa is a major risk factor of progression of lung disease in patients with cystic fibrosis (CF). Chronic P. aeruginosa infection evolves from intermittent infection that is amenable to antibiotic eradication, whereas chronically adapted P. aeruginosa becomes resistant to antibiotic therapy. Discrimination of intermittent versus chronic infection is therefore of high therapeutic relevance, yet the available diagnostic methods are only partly satisfactory. The aim of the present study was, therefore, to evaluate the usage of quantitative PCR (qPCR) to measure pathogen abundance and to discriminate between intermittent and chronic Pseudomonas infection in patients with CF.

Method: Using an established qPCR protocol, we analyzed the abundance of P. aeruginosa in 141 throats swabs and 238 sputa from CF patients with intermittent or chronic infection with P. aeruginosa, as determined by standard culture based diagnostics.

Results: We observed a large increase of abundance of P. aeruginosa in throat swabs and sputum samples from patients with chronic compared to intermittent infections with P. aeruginosa. The data show that abundance of P. aeruginosa as measured by qPCR is a valuable tool to discriminate intermittent from chronic infection. Of note, P. aeruginosa burden seems more sensitive than mucoidity phenotype to discriminate chronic from intermittent strains. Furthermore we observed that molecular detection in throat swabs was linked to a viable culture in the sputum when sputum was available. This result is of special interest in young patients with cystic fibrosis that often cannot expectorate sputum. We also observed that qPCR in comparison to culture detected the infection earlier.

Conclusion: The results suggest that qPCR detection and quantification of P. aeruginosa is a precious tool to be added to the diagnostic toolbox in cystic fibrosis.

Keywords: Chronic infection; Diagnostic; Pseudomonas aeruginosa; Quantitative PCR.

Publication types

Observational Study
Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Bacteriological Techniques / methods
Chronic Disease
Cystic Fibrosis* / epidemiology
Cystic Fibrosis* / microbiology
Cystic Fibrosis* / physiopathology
Disease Progression
Female
Germany / epidemiology
Humans
Male
Patient Acuity
Pharynx / microbiology
Pseudomonas Infections* / diagnosis
Pseudomonas Infections* / epidemiology
Pseudomonas Infections* / physiopathology
Pseudomonas aeruginosa* / genetics
Pseudomonas aeruginosa* / isolation & purification
Real-Time Polymerase Chain Reaction / methods
Young Adult