S62 The microbiology of bronchiectasis exacerbations in the UK EMBARC registry and implications for prescribing in primary care: A cohort study

<h3>Introduction</h3> The British Thoracic Society (BTS) guidelines for the management of Bronchiectasis advise that sputum samples are sent for microbiology at baseline and at exacerbation. Guidelines recommend that antibiotic treatment at exacerbations should be guided by previous sputum microbiology. Amoxicillin and Doxycycline are guideline recommended empirical choices in primary care where no prior microbiology is available. <h3>Methods</h3> We aimed to examine the UK cohort of the European Multicentre Bronchiectasis Registry (EMBARC) to determine whether management of these patients was in line with BTS guideline recommendations and examine antibiotic sensitivities at exacerbation. The organisms grown were identified and their sensitivity to amoxicillin and doxycycline, using sputum culture sensitivity data, was defined. <h3>Results</h3> 7931 UK patients were analysed. 53.3% of patients had sputum sent at baseline and of those with exacerbations 42.3% had a sputum sample sent at exacerbation within 1 year of baseline. 21.7% of exacerbating patients had a prior stable sputum result available to guide exacerbation prescribing with only 34.8% of these showing concordance, with baseline sputum microbiology predictive of exacerbation sputum microbiology. Haemophilus influenzae (25.7%) and Pseudomonas aeruginosa (19.8%) are the most common organisms grown at exacerbation. Examination of all organisms grown at first exacerbation shows that 36.2% of these are susceptible to amoxicillin and 55.6% are susceptible to doxycycline. The difference in susceptibility between amoxicillin and doxycycline was largely accounted for by beta-lactamase producing H.influenzae, Moraxella catarrhalis and Staphylococcus aureus. Excluding P. aeruginosa gives 47.2% coverage of remaining organisms by amoxicillin and 73% coverage with doxycycline. <h3>Conclusion</h3> Concordance with BTS guidelines on management of Bronchiectasis is low with sputum samples sent infrequently in stable state and at exacerbation. Microbiology concordance between stable and exacerbation samples is poor. There are high levels of innate and acquired resistance to amoxicillin making doxycycline potentially a more effective first choice antibiotic where no sputum culture results are available to guide prescribing.