Background: Oral and topical corticosteroids, and antibiotics form the mainstay medical treatment of chronic rhinosinusitis (CRS). Clinical outcomes vary depending on the chosen therapy, resident microbiome and disease phenotype. We conducted a double- blinded, placebo-controlled Randomised Controlled Trial (RCT) to investigate effects of medical therapy on clinical outcomes and associated microbiome shifts.
Methodology: Fifty eligible patients (CRS with and without polyps) were treated for 3 weeks after randomisation into 3 arms: na- mely oral prednisolone, topical budesonide irrigations and oral doxycycline; each with appropriate placebo. Clinical scoring and microbiome swabs were performed on enrolment, at treatment completion and 3-weeks post treatment completion. Microbiome analysis was performed using the llumina-MiSeq next generation sequencing platform and QIME-2 pipeline.
Results: Significant improvement in clinical scores was observed in prednisolone and budesonide arms at treatment completion but not with antibiotic. Sub-group analysis showed more pronounced effects in patients with polyposis. Corynebacterium and Staphylococcus species predominated, with variable bacterial relative abundance among different treatments at all time-points. The only significant microbiome finding was an increase in bacterial diversity in topical budesonide group immediately after treatment, which returned to baseline 3-weeks post treatment.
Conclusion: Clinical improvement was significant with oral and topical steroid but not empirical antibiotic. Although there were some associated microbiome changes with the various treatments, we could not ascertain the consistency of these and whether they do have a clinical significance at all.