MOLECULAR DIAGNOSIS OF BACTERIAL INFECTION IN THE LUNG (360G-Wellcome-207235_Z_17_Z)

Patients with chronic respiratory diseases such as bronchiectasis and COPD suffer from frequent exacerbations (chest infections) that are typically treated with antibiotics +/- corticosteroids. The goal of treatment with preventative measures is to reduce the frequency of chest infections and this is the major end-point in most randomized trials of new drugs in these diseases. Previous dogma held that the airways were sterile and that exacerbations were caused by exogenous acquisition of bacteria from the environment. More recent work suggests that the bacteria isolated during exacerbations are often found in the lungs when patients are well and that they may represent an overgrowth or alteration in the natural microbial flora of the lungs (the microbiome). We hypothesise that if this is true, the presence of pathogenic bacteria at low levels in the lung when patients are well will predict future bacterial chest infections. 1. To test the hypothesis that the presence of bacteria known to be associated with exacerbations(particularly Haemophilus influenzae and Pseudomonas aeruginosa) in the sputum microbiome is associated with the future risk of exacerbations of bronchiectasis over 1 year follow-up 2. To test whether the bacterial load of these pathogens is associated with an increased risk of exacerbations.