Total bacterial load and load for different PPMs; COPD vs. HNS controls at 6 months. Sputum from COPD patients (n = 39) at 6 months visit and healthy non-smokers (n = 15) were analysed for qPCR for presence of H. influenzae, S. pneumoniae, M. catarrhalis and P. aeruginosa. Data represent bacterial genome copies for individual patients for (a) total bacterial load and that for different bacterial species; (b) H. influenzae, (c) S. pneumoniae, (d) M. catarrhalis and (e) P. aeruginosa. COPD, Chronic obstructive pulmonary disease; HNS, healthy non-smoker; HI, Haemophilus influenzae; MC, Moraxella catarrhalis; PPM, potentially pathogenic microorganism; PA, Pseudomonas aeruginosa; SP, Streptococcus pneumoniae.