RESUMO
BACKGROUND AND OBJECTIVES: Biofilm is an encased colony of bacteria and the bacteria with-in the biofilm have resistance to antibiotics and the humoral immune system. Biofilm is currently thought to play an important role and to be very refractory to conventional therapeutics. The aim of this study is to analyze the relationship between the biofilm of the tonsil and recurrent tonsillitis with a case-control study. SUBJECTS AND METHOD: This is a case-control study. The case group included 31 patients who had histories of tonsillitis and the control group included 29 volunteers who had no history of tonsillitis. Confocal laser scanning microscopy was performed to identify biofilms. We compared the prevalence rates of biofilm between the 2 groups. Fluorescent in situ hybridization (FISH) was performed to identify bacteria, using probes for S. aureus, S. pyogenes, H. influenzae, S. pneumoniae, and K. pneumonia. RESULTS: In case group, biofilms were found in 22 (71.0%) of 31 and in control group, biofilms were found in 12 (41.4%) of 29. The prevalence rates of biofilm were significantly higher in case group (p=0.036). Twenty nine cases were enrolled in FISH and 12 cases of them were positive for FISH. S. aureus was most commonly identified. CONCLUSION: This study suggests that the biofilms could play a causative role in recurrent tonsillitis, further studies are needed to confirm pathogenic relation between biofilm and recurrent tonsillitis.