TY - JOUR T1 - Comparison of quantitative PCR and quantitative culture for the detection of airway pathogenic bacteria in COPD JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P568 AU - Richa Singh AU - Sarah Thurston AU - Alexander Mackay AU - Beverly Kowlessar AU - James Allinson AU - Simon Brill AU - Gavin Donaldson AU - Jadwiga Wedzicha Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P568.abstract N2 - There has been increasing interest in the use of culture-independent techniques to study the airway microbiome of COPD patients. We compared quantitative PCR (qPCR) technique with quantitative culture for the detection of airway potentially pathogenic microorganisms (PPMs).146 prospectively collected sputum samples from 84 patients in the London COPD cohort were analysed by qPCR to detect the typical airway PPMs, H. influenzae, S. pneumoniae and M. catarrhalis, and by quantitative culture.92/146 (63%) sputum samples had PPMs detected by qPCR compared to 48/146 (33%) by quantitative culture (χ2 p<0.001). In 42 sputum samples, PPMs were detected by both qPCR and quantitative culture. The Log10 total PPM load measured by both methods was compared using a Bland-Altman plot (Figure 1).Although an agreement between the two methods is seen, the mean difference between qPCR and quantitative culture was -1.67, with limits of agreement of 1.88 to -5.29. As the PPM loads increase, there is a closer agreement between the two methods.In samples with PPMs detected by both qPCR and quantitative culture, the PPM loads are related to each other, but are not equivalent, although the difference decreases with higher PPM loads. However, the qPCR method detects a higher prevalence of typical airway PPMs than quantitative culture, and thus should be considered for future studies of the airway microbiome. ER -