The impact of bitter taste receptor genetics on culturable bacteria in chronic rhinosinusitis

Background: Extra-oral bitter taste receptors have been associated with innate bacterial defence mechanisms. Genetic variation in T2R38 functionality has been shown to be associated with susceptibility to upper respiratory tract infections and chronic rhinosinusitis (CRS). We sought to independently assess the influence of bitter taste receptor genotype on the presence of culturable bacteria in the sinuses. Methodology: A cross-sectional analysis of patients with CRS undergoing surgery was performed. Middle meatal nasal swabs were sent for microbiological evaluation at the time of the procedure. Mucosal biopsies were taken and sent for bitter taste receptor genotype analysis. Sequencing of 3 polymorphisms in the TAS2R38 gene was performed to identify genotypes as super-tasters (PAV/PAV), non-tasters (AVI/AVI) or heterozygous expression (PAV/AVI). The presence of culturable organisms and common pathogens were compared with bitter taste receptor genotypes. Results: 25 patients (age 52.4±18.28 years, 51% female) were assessed. Super-tasters comprised 16% of the group, 24% were non-tasters and 48% had heterozygous expression. A cultured pathogen was grown in 48% of patients; 32% gram-positive, 20% gram-negative, 28% grew Staphylococcus aureus and 12% Pseudomonas aeruginosa. A non-taster genotype was predictive of colonised pathogens. Tissue eosinophilia (>10/HPF) was seen in 48%. Conclusion: Even in a small sample of patients with CRS, non-taster T2R38 genotype appears to predict the presence of culturable bacteria colonising the sinus cavity at the time of surgery for their condition. A genetic link to patients more likely to become ‘infected’ is likely.