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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Adolescent, Adult, Antibodies, Bacterial, Biofilms, Child, Cystic Fibrosis, Endoscopy, Female, Gram-Negative Bacterial Infections, Humans, Immunoglobulin A, Immunoglobulin G, Male, Middle Aged, Neutrophils, Paranasal Sinuses, Pseudomonas Infections, Pseudomonas aeruginosa, Sinusitis, Sputum, Streptococcal Infections, Young Adult.
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Is colonisation and infection of the paranasal sinuses in cystic fibrosis patients accompanied by a reduced PMN response? Context: We studied whether the sinuses might be foci for Pseudomonas aeruginosa lung infection. Endoscopic Sinus Surgery was performed in 78 CF patients; PFGE was used for bacterial genotyping. Material from sinuses and lungs were Gram-stained to detect biofilms. Immunoglobulins were measured in serum and saliva. When P. aeruginosa was cultured simultaneously from the sinuses and the lungs they were genetically identical in 38 of the 40 patients (95%). In the sinuses, P. aeruginosa formed biofilms with minimal cellular inflammation, probably because of a significantly higher local production of secretory IgA compared with IgG (p<0.001).
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We have shown that P. aeruginosa form biofilm in the sinuses, which constitute an important bacterial reservoir for subsequent lung infection. The high amount of IgA in the upper airways probably protects P. aeruginosa from the inflammatory immune system, and they can proceed unnoticed into a permanent infectious focus that cannot be eradicated with antibiotics. Final Decision: yes