Assessment of Sino-nasal Microbial Communities Changes in Adult Patients With Chronic Rhinosinusitis by 16 rRNA Gene Amplicon Sequencing Before and After 1-month Treatment Duration With Healsea® Chronic: an Exploratory Study

Chronic rhinosinusitis (CRS) is an inflammation of the nose and paranasal sinuses and is characterized by two or more symptoms, one of which should be either nasal blockage/obstruction/congestion or nasal discharge (anterior/posterior nasal drip), lasting for 12 weeks or longer. In addition, facial pain or pressure and a reduction in the sense of smell can occur. The condition can occur with or without nasal polyps.

Chronic rhinosinusitis (CRS) is a significant health problem and affects 5-12% of the general population.

The physiopathology of CRS is poorly understood with multiple environmental, host and microbial factors being implicated. Putative pathological factors include changes in the microbiota, imbalance of the local or systemic immune system, allergens, toxins and genetic predisposition.

A dysbiosis mechanism has been proposed as modulating inflammation in diseased sinuses. This hypothesis suggests that externally influenced changes in the nasal microbiome can result in dysbiosis, i.e. a shift from a "normal" or "healthy" microbial community structure and that this shift may be responsible for the initiation or maintenance of CRS. For example, the disruption of the commensal biofilm during a viral upper respiratory tract infection can create a niche for pathogenic species to grow. Despite many contradictory statements in the different studies some common trends emerge. Less diversity in the microbial community rather than an increased overall bacterial load seems to characterize CRS compared to the healthy state with no consensus about specific genera indicative of disease. However, anaerobes and S. aureus are found to be significantly more prevalent and abundant in CRS versus healthy controls. Bacterial biofilm is detected on the sinus mucosa in up to 80% of CRS patients and its presence does not imply that it is causing mucosal inflammation. However, in the context of CRS, there are several possible mechanisms by which biofilms may be pro-inflammatory including the release of planktonic organisms and the release of superantigens, which can cause ciliary dysfunction and inhibition of ciliary clearance. Bacterial biofilms are likely a key modulator of the refractory nature of CRS.

Although clinical evidence from well-designed trials is scarce, European Guidelines for chronic rhinosinusitis recommend daily nasal saline irrigation for reduction of the severity of symptoms of CRS. A recent Cochrane analysis has concluded that daily nasal irrigation with hypertonic saline solution is more effective than placebo to improve patient symptoms. The exact mechanisms by which nasal irrigation works are not known. However, most of the experts agree that it is primarily a mechanical intervention leading to direct cleansing of the nasal mucosa. Nevertheless, the efficacy of such solution remains moderate.