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Ở người lớn, CRS truyền nhiễm phổ biến polymicrobial, và vi khuẩn gram dương và gram âm hiếu khí và kỵ khí thường xuyên bị cô lập. Một loạt các vi khuẩn hiếu khí, chẳng hạn như Staphylococcus coagulase tiêu cực, S. aureus, Streptococcus viridans, P.aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, và Enterobacter spp. đã được cô lập | Pathophysiology of Sinusitis 125 relative contribution of anaerobic bacteria has been debated and the large variations in rates of isolation have been attributed to culture techniques. Brook reported that up to 50 of cases of CRS were culture-positive for anaerobic bacteria with the predominance of Prevotella Fusobacterium and Peptostreptococcus spp. 56 57 . In adults infectious CRS is commonly polymicrobial and both gram-positive and gram-negative aerobic and anaerobic bacteria are frequently isolated. A wide variety of aerobic bacteria such as coagulase negative Staphylococcus S. aureus Streptococcus viridans P.aerugi-nosa Klebsiella pneumoniae Proteus mirabilis and Enterobacter spp. have been isolated. Also several different anaerobic species have been demonstrated including Prevotella Fusobacterium and Peptostreptococcus spp. 56-64 . Biofilms. Biofilms are sessile bacterial microcolonies that are enclosed in a highly hydrated polysaccharide matrix with interstitial voids in which nutrients and signaling molecules can be circulated. The structural and functional heterogeneity of bacterial cells within these communities protects them against the body s natural defenses and provides them with antimicrobial resistance. Through genetic alterations bacteria in biofilms are also able to transition to the mobile planktonic form which has been the traditional model for studying bacterial diseases 65 66 . Bacterial biofilms have been demonstrated on many areas of mucosa in the human body including the ear mucosa and tympanostomy tubes removed from patients with chronic effusions and infections 67 68 . It has been hypothesized that biofilms may play an important role in cases that are refractory to antibiotic therapy and antibiotic resistance has been demonstrated to be up to 1000-fold greater in bacteria in the biofilm form versus the planktonic form 66-70 . Similarities between chronic otitis media and CRS exist. Both of these disease processes take place in the .
