Microbiota Transfer for Chronic Rhinosinusitis

Inclusion Criteria for Patients:

• Recalcitrant CRS patients

• Able to provide informed consent

• Diagnosed with CRS (with/without polyps) and have previously undergone functional endoscopic sinus surgery (Post-FESS)

• Continued to fail despite receiving "maximal and adequate medical treatment" This is defined as patients who:

• Have received topical nasal steroids in any form (Spray/ Rinse/ Atomized) for at least 3 months or at least one course of oral corticosteroids treatment (>0.5 mg/kg for 2 weeks tapering dose);

• Had at least one course of antibiotic treatment either based on culture and sensitivity of nasal sinus secretions or as long-term low dose macrolide therapy (clarithromycin 500mg twice a day for 2 weeks then 250 mg once a day for 4 weeks) for at least one trial or have received a course of itraconazole 100mg twice daily for 6 weeks

• Have deteriorating SNOT-22 Scores (≥20) or do not improve after surgery and appropriate maximal medical management (MLK score ≥ 2, with at least 2 points on the discharge subdomain)

Exclusion Criteria for Patients:

• Diagnosed with sinonasal tumors

• Autoimmune diseases affecting the upper airway (e.g., systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis)

• Immune-compromised patients

• Impairment in mucociliary function (e.g., cystic fibrosis, Kartagener syndrome)

• Pregnant or planning to become pregnant or breastfeeding

• Severe underlying disease with anticipated survival less than 6 months

• Unable to tolerate SNMT for any reason

Inclusion Criteria for Donors:

• 19 years of age or older

• Able to provide informed consent, complete donor screening, and adhere to SNMT mucus collection and testing procedures

Exclusion Criteria for Donors:

• If they are positive for any of the following: (i) from blood or mucus testing, human Immunodeficiency virus (HIV) I/II, hepatitis A IgM, hepatitis B surface antigen (HBsAg), hepatitis C, human T- lymphotropic virus (HTLV) I/II, methicillin-resistant Staphylococcus aureus, multidrug resistant bacteria, and/or SARS-CoV-2

• A history of sinonasal or lower airway disease within the last 2 years other than the common cold; diagnosed with CRS; diagnosed with acute rhinosinusitis within the last six months; asthma; and/or clinical findings of sinonasal disease at the inclusion visit and immunodeficiency; any history of active cancer, or risk factors for acquisition of HIV, syphilis, hepatitis A, hepatitis B, hepatitis C, prion, or relevant neurological disease, receipt of blood transfusion from a country other than Canada in the preceding 6 months, any type of antibiotic treatment or any systemic immunosuppressive agents in the 3 months prior to the donation, or any current or previous medical or psychosocial condition or behaviours, which in the opinion of the investigator, may pose a risk to the recipient or the donor