Evolution of the Endonasal Microbiota in Patients With Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is defined according to the French society of otorhinolaryngology as chronic non-mechanical damage to the nasal structures, excluding infectious damage to the sinus structures. The duration of the chronic impairment must be at least 12 consecutive weeks. It causes many symptoms such as rhinorrhea, nasal blockage and anosmia. It is a poorly understood pathology that affects a large part of the population. Its prevalence has increased significantly over the past 30 years. It affects about 11% of the population in Europe. It has become one of ten high-cost medical conditions for employers. Initially, it was accepted that CRS was due to chronic nasal infection. It is very debilitating for patients leading to a major consultation with practitioners (general practitioners and ENT specialists). Many treatments are used such as nose washes, nasal or oral corticosteroids, antibiotic therapy or even surgical management is possible. Thèses treatments allow an improvement in the symptomatology but no treatment allows a stable result over time, making long-term treatments essential. Today, it is recognized that CRS has a multifactorial etiology including inflammatory processes, hyperresponsiveness of the nasal mucosa and abnormalities in immune phenomena. The endonasal microbiota plays a role in these processes. Germs like Staphylococcus aureus and Pseudomonas aeruginosa were identified as pathogens in CRS in the first studies with bacterial cultures. Thanks to the 16S ribosomal RNA sequencing technique, recent studies have demonstrated a modification in the diversity and abundance of the microbiota in patients with CRS compared to healthy subjects, notably with a modification of the germs of the firmicutes group. . Few studies have studied the modification of the microbiota with the treatment of CRS today. However, local treatments based on nosewashing with physiological saline associated with local corticosteroids and endoscopic treatments lead t