Nasal colonization with Staphylococcus aureus associates with nasal polyps, toxin-sensitization and inflammation depending on aeroallergen-sensitization

<bold>Background:</bold> <italic>Staphylococcus aureus</italic> (SA) nasal carriage and sensitization to SA enterotoxins are associated with asthma. The mechanisms and implications remain elusive. <bold>Aims and objectives:</bold> We address associations between SA nasal carriage, enterotoxin-specific sensitization, inflammation and nasal polyps in patients with asthma discriminating between aeroallergen-sensitized and unsensitized patients. <bold>Methods:</bold> We assessed SA nasal colonization, sensitization to aeroallergens and SA toxins, nasal lavage and serum cytokines and the history of nasal polyps in 62 asthma patients. <bold>Results:</bold> Of 62 patients, 24 were SA carriers (39%). Carriers had undergone significantly more nasal polyp surgeries and had significantly higher serum interleukin (IL)-4. In the non-aeroallergen-sensitized group (n=36), 33 % were SA carriers. SA carriage significantly associated with higher serum IL-4, IL-13 and IL-23. Aeroallergen-specific sensitization was present in 26 patients, 46% of these carried SA. Here, SA carriage significantly associated with more nasal polyp surgeries and higher nasal lavage TNF-a. In the aeroallergen-sensitized asthma patients, SA carriage was significantly associated with stronger sensitization towards enterotoxins A and B (kU/L and % of total IgE) as well as toxic shock syndrome toxin 1 (% of total IgE). <bold>Conclusion:</bold> SA carriage is associated with a history of nasal polyp surgery, especially in allergic asthma. SA affects local and systemic inflammation depending on aeroallergen-sensitization. In aeroallergen-sensitized patients, SA colonization significantly associates with toxin-specific sensitization.