Background: Infections in CRS may be related to a decrease in native and an increase in pathogenic bacteria.  Topical probiotics outcompete pathogenic bacteria via a variety of mechanisms, including creating suboptimal environmental conditions, competing for cell surface receptors and thus limiting pathogen adherence, and producing antibacterial metabolites.  In doing so, topical probiotics can restore the native microbiome.

Objective: Assess if topical probiotic sinus irrigations can improve outcomes compared to standard treatments in patients with recalcitrant chronic rhinosinusitis.