M-S培地で分離される口腔レンサ球菌のA群レンサ球菌発育抑制

Abstract

It is known that some oral streptococci possess inhibitory activity against the growth of pathogenic group A streptococci. To examine the inhibitory activities of oral streptococci in more detail, we used Mitis-Salivarius (M-S) plate in this study to isolate inhibitory oral streptococci against group A streptococci from the oral flora and compared the results with those on blood agar (B-A) plate. Utilizing the M-S plate, we could isolate S. mitis and S. salivarius from the oral bacterial flora selectively, which have been known to have strong growth inhibitory activities against group A streptococci.We also examined oral bacterial flora of 27 patients who underwent tonsillectomy because of chronic tonsillitis.1) Using M-S plates, we could isolate more strains of oral streptococci with inhibitory growth actibities from the throat flora than using B-A plates.2) After tonsillectomy, streptococci with strong inhibitory activities were more frequently isolated using M-S plate than B-A plate.3) These results suggest the M-S plates are more useful for evaluating post-operative improvement in oral bacterial flora since the isolation rate was much higher using M-S plates than that using B-A plates.