University of Leicester
Browse
Airway bacteria measured by quantitative polymerase chain reaction and culture in patients with stable COPD: relationship with neutrophilic airway inflammation, exacerbation frequency, and lung function..pdf (733.02 kB)

Airway bacteria measured by quantitative polymerase chain reaction and culture in patients with stable COPD: relationship with neutrophilic airway inflammation, exacerbation frequency, and lung function

Download (733.02 kB)
journal contribution
posted on 2016-01-26, 13:19 authored by M. Bafadhel, Koirobi Haldar, Bethan Barker, Hemu Patel, Vijay Mistry, Michael Richard Barer, I. D. Pavord, Christopher E. Brightling
BACKGROUND: Potentially pathogenic microorganisms can be detected by quantitative real-time polymerase chain reaction (qPCR) in sputum from patients with COPD, although how this technique relates to culture and clinical measures of disease is unclear. We used cross-sectional and longitudinal data to test the hypotheses that qPCR is a more sensitive measure of bacterial presence and is associated with neutrophilic airway inflammation and adverse clinical outcomes. METHODS: Sputum was collected from 174 stable COPD subjects longitudinally over 12 months. Microbial sampling using culture and qPCR was performed. Spirometry and sputum measures of airway inflammation were assessed. FINDINGS: Sputum was qPCR-positive (>10(6) copies/mL) in 77/152 samples (Haemophilus influenzae [n=52], Moraxella catarrhalis [n=24], Streptococcus pneumoniae [n=19], and Staphylococcus aureus [n=7]). Sputum was culture-positive in 50/174 samples, with 49 out of 50 culture-positive samples having pathogen-specific qPCR bacterial loads >10(6) copies/mL. Samples that had qPCR copy numbers >10(6)/mL, whether culture-positive or not, had increased sputum neutrophil counts. H. influenzae qPCR copy numbers correlated with sputum neutrophil counts (r=0.37, P<0.001), were repeatable within subjects, and were >10(6)/mL three or more times in 19 patients, eight of whom were repeatedly sputum culture-positive. Persistence, whether defined by culture, qPCR, or both, was associated with a higher sputum neutrophil count, lower forced expiratory volume in 1 second (FEV1), and worsened quality of life. INTERPRETATION: qPCR identifies a significant number of patients with potentially bacteria-associated neutrophilic airway inflammation and disease that are not identified by traditional culture-based methods.

History

Citation

International Journal of Chronic Obstructive Pulmonary Disease, 2015, 10, pp. 1075-1083

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Medicine/Department of Infection, Immunity and Inflammation

Version

  • VoR (Version of Record)

Published in

International Journal of Chronic Obstructive Pulmonary Disease

Publisher

Dove Medical Press

issn

1176-9106

eissn

1178-2005

Acceptance date

2015-02-20

Copyright date

2015

Available date

2016-01-26

Publisher version

https://www.dovepress.com/airway-bacteria-measured-by-quantitative-polymerase-chain-reaction-and-peer-reviewed-article-COPD

Language

en

Usage metrics

    University of Leicester Publications

    Categories

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC