Biofilms in chronic rhinosinusitis: systematic review and suggestions for future research

Background: A biofilm is a community of micro-organisms encased within a self-produced, extracellular, polymeric substance. The role of biofilms as a major pathological aetiology in chronic rhinosinusitis would help explain the clinical manifestation of the disease. Objectives: To examine the current evidence, and to discuss possible future research directions, in relation to biofilms and chronic rhinosinusitis. Study design: Systematic literature review. Evaluation method: Two assessors independently undertook critical appraisal of the studies identified by the literature search. Significant findings were incorporated into this review. The primary outcome assessed was the presence of biofilm in human mucosal biopsy samples taken from patients with chronic rhinosinusitis, and from healthy controls. Results: We identified 11 studies examining biofilm formation in human mucosal biopsy samples taken from patients with chronic rhinosinusitis. Conclusion: It is unlikely that biofilms occur in every case of chronic rhinosinusitis; consequently, the significance of 'biofilm detection' in some series should be considered carefully. Several authors have argued strongly for the use of confocal scanning laser microscopy with fluorescent in situ hybridisation probes as the 'gold standard' for biofilm imaging. This imaging modality should be combined with further investigation of the microbiology of chronic rhinosinusitis, and of the efficacy of traditional culture techniques used for pathogen identification.