Interaction between oral alpha-streptococci and group A streptococci in patients with tonsillitis.

The incidence of oral alpha-streptococci with inhibitory activity against group A streptococci, as a defense mechanism against bacterial infection in the oral cavity, was investigated in 141 patients with streptococcal tonsillitis. The study population included both children (n = 79) and adults (n = 62). Infection by group A streptococci appeared to be more common in children than in adults, as the detection rates of inhibitory alpha-streptococci in healthy children (29.7%), as well as pediatric patients with tonsillitis (14.9%), were lower than those in adults (63.0%; p < .01). It is possible to consider oral alpha-streptococci with inhibitory activity to be among the indications for tonsillectomy in patients with streptococcal tonsillitis, since the detection rate of inhibitory alpha-streptococci in surgical cases (10.9%) was significantly lower than that in nonsurgical cases (31.1%; p < .01). The high detection rate of these strains during the postoperative state supported the observation that the incidence of group A streptococcal infection was decreased postoperatively. Accordingly, it is useful to investigate bacterial interference between oral alpha-streptococci and group A streptococci in patients scheduled for tonsillectomy.