LSC Abstract – Bacterial burden in rhinovirus-induced asthma exacerbations

Abstract

Introduction: Rhinoviruses (RVs) are the major cause of asthma exacerbations (AEs). The role of bacteria in AEs is unclear, yet antibiotics are commonly prescribed. However, recent evidence suggests that viral infections may enhance the secondary bacterial infections. We hypothesised that the airway bacterial burden (BB) increases in virus-induced AEs. Objective: To assess the airway BB of asthmatic and healthy individuals in the context of RV infection. Methods: Asthmatic (n=28) and healthy (n=11) subjects were experimentally infected with RV and bronchoalevolar lavage was obtained before and four days after RV infection. Eight additonal subjects without RV infection were sampled. BB was assessed using 16S rRNA quantitative polymerase chain reaction. Results: Asthmatics had lower BB than healthy subjects at baseline (p=0.02). BB did not increase significantly with RV infection in both asthmatic and healthy subjects, though a minorty (15%) had large increase (up to 335 fold). Disease severity and control did not affect BB. Furthermore, BB was not associated with increased symptoms or reduced spirometry with RV infection. BB of non-RV infected subjects did not differ from other groups. Conclusion: BB did not increase with RV infection in health or asthma. Examination of microbial community membership may reveal changes in the relative abundance of bacterial species with clinical relevance. Asthmatics appear to have lower BB and further investigation is warranted. The airway bacterial burden in health and asthma in RV infection. ![Figure][1] [1]: pending:yes