Evidence of microbiota dysbiosis in chronic rhinosinusitis

Despite considerable research, the pathogenesis of chronic rhinosinusitis (CRS) remains poorly understood. Potential microbial roles in the etiology or progression of CRS have long been hypothesized, yet few specific associations have been identified. In this study we investigate associations between patterns in resident bacterial communities and clinical variants of CRS.

Bacterial communities were assessed in 94 patients with extensive bilateral CRS undergoing endoscopic sinus surgery (ESS) and 29 controls undergoing ESS for indications other than CRS. Patients were grouped on the basis of phenotypic variants (with or without polyposis) and clinical parameters, including asthma and cystic fibrosis. Bacterial communities were characterized via 16S rRNA gene amplicon sequencing, and quantified by quantitative polymerase chain reaction.

Controls and idiopathic CRS subjects tended to be dominated by members of the genera Corynebacterium and Staphylococcus, together with lower abundances of several other genera, including Streptococcus, Moraxella, and Haemophilus. Aberrant (dysbiotic) bacterial assemblages (with changes in community membership and structure, reduced diversity, and increased bacterial load) and increased inter- and intrasubject variability were more common in subjects with comorbidities such as asthma and cystic fibrosis. Dysbiotic communities were variably dominated by members of the genera Staphylococcus, Streptococcus, Haemophilus, Pseudomonas, Moraxella, or Fusobacterium.

Bacterial community dysbiosis was more apparent than specific associations with examined phenotypes or endotypes, and may play a role in the pathogenesis or influence the severity of CRS. Reductions in several common core bacterial taxa, increased inter- and intrasubject variability, reduced bacterial diversity, and increased bacterial load characterized aberrant bacterial communities in CRS.