The CRS Problem
CRS Patient Population is Currently Not Adequately Treated
CRS patients are inadequately treated by both medical and surgical therapies. Antibiotics and steroids are relatively ineffective against intractable biofilms involving both bacterial and fungal constituents, and are unsuitable for long term use due to systemic side-effects and resistance development. Current surgical procedures are aimed at improving mucociliary clearance and reducing blockage, but are not directed towards treating underlying infections. Failure rates of surgeries are high and range between 10-40%, with presence of polyps correlating to poorer outcome. 70% of polyps reoccur post surgery.
Bacterial biofilms have been implicated in the vast majority of chronic sinusitis cases. A biofilm is a complex community of a number of different microorganisms coexisting together and marked by the excretion of a protective and adhesive matrix called extracellular polymeric substance or exopolysaccharide. That matrix holds the biofilm together, protects the cells within it and facilitates communication among bacteria through biochemical signals. Recent studies have demonstrated that biofilms involving known superantigen-producing bacteria such as Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, are prevalent in CRS. In addition, Gram-negative and Gram-positive bacteria, including Hemophilus influenzae and Streptococcus pneumoniae account for 50% of clinically sampled isolates found in CRS patients. The presence of these particular biofilms has been shown to correlate with unfavorable treatment outcome, even after aggressive antibiotic therapy and surgery for CRS.
Antibiotic resistant strains of these bacteria also contribute significantly to poor clinical results with the prevalence of antibiotic resistant strains in clinical isolates being as high as 30%. Although antibiotics are only one of several treatment modalities for CRS patients, the recognition of antibiotic resistance on the world stage further demonstrates the challenges faced by physicians in effectively treating CRS patients. The World Economic Forum (WEF) has concluded in a recent report on global risks that “arguably the greatest risk…to human health comes in the form of antibiotic-resistant bacteria”.
Eradication of these biofilms and associated virulence factors, as well as suppression of the exuberant host response, is important in effectively and successfully dealing with the disease. It has been observed that patients with residual sinus biofilms after treatment demonstrate increased postoperative symptoms, ongoing mucosal inflammation and recurrent infections. After years of chronic symptomatology, many patients demonstrate substantial sinus ciliary destruction which in turn impairs mucociliary defense mechanisms and further predisposes the patient to recurrence of symptoms.