Distribution and Adherence Properties of Oral Streptococci with Fimbriae

Abstract

     We identified fimbriae-positive streptococci isolated from buccal mucosa, supragingival plaque and saliva, and examined their distribution and adherence properties. Of 349 strains isolated, 119 possessed peritrichous fimbriae or fimbrial tufts projecting from streptococcal cell surfaces. Based on biochemical characteristics and DNA-DNA hybridization, all strains tested were identified as either S. salivarius or S. oralis. S. salivarius cells were abundant in supragingival plaque and saliva, while S. oralis cells were predominant in buccal mucosa. As a result, all strains of S. salivarius possessed peritrichous fimbriae, while fimbrial tufts were present on 50% of S. oralis. S. salivarius were more hydrophobic (an average of 28.6%), followed by type D of S. oralis (43.0%) and type A of S. oralis (68.4%). S. salivarius had more capacity to adhere to human buccal epithelial cells and to form in vitro plaque than S. oralis. Moreover, hydrophobicity and the ability to adhere to epithelial cells of S. salivarius with short fimbriae, designated as type Aa, differed from S. salivarius with long fimbriae, designated as type Ab. These results indicate that there are several adhesins on the fimbriae of S. salivarius and S. oralis, and that S. salivarius have more pathogenic potential than S. oralis.