Experimental and Clinical Studies of Causative Bacteria in Tonsillitis

To study the pathogenesis of upper respiratory tract infections, we focused on acute tonsillitis and performed three experimental and clinical studies. From these studies, we found out that there seemed to be an intimate relationship between anatomical structure and adherence of S. pyogenes, and we confirmed that the M protein of S. pyogenes played an important role in adherence to the epithelium and the normal bacterial flora was actively involved in the body's defense against infections. We also identified that nearly half of causative bacteria in tonsillitis in Japan were the genus streptococcus, especially S. pyogenes with 23.4%. The incidence of Methicillin (DMPPC)-resistant Staphylococcus aureus (MRSA) was 27% in middle ear exudate and 14.3% in nasal discharge, but no MRSA was isolated from tonsillitis.