Ability of Veillonella and Neisseria Species to Attach to Oral Surfaces and Their Proportions Present Indigenously

The present study describes the distribution of Veillonella and Neisseria species in the human oral cavity and indicates that their ability to attach to oral surfaces correlates with their proportions found in various sites of the mouth. The mean percentages of Veillonella and Neisseria of the total flora cultivable on anaerobic blood-agar plates was found to be: plaque, 0.75 and <0.13, respectively; lip, 0.38 and <0.05; cheek, 0.66 and <0.14; tongue dorsum, 9.4 and <0.12; saliva, 5.0 and <0.9. The ability of Veillonella and Neisseria species to attach to tooth surfaces was studied by cleaning the labial surfaces of incisors to render them relatively free of viable bacteria. Samples taken 1 hr later contained <0.27% Veillonella and <0.4% Neisseria, whereas saliva to which these teeth were exposed contained 20-fold higher proportions of Veillonella. These data indicate that Veillonella and Neisseria species possess a feeble ability to attach to cleaned teeth. The ability of these organisms to adhere to other oral surfaces was determined by introducing mixtures of streptomycin-resistant strains into the mouths of volunteers for 5 min. Labeled strains of Streptococcus sanguis and S. salivarius were included for comparative purposes. Analysis of samples obtained from oral surfaces after 45 min indicated that Veillonella and Neisseria adhere very poorly to preformed dental plaque as compared to S. sanguis. In contrast, Veillonella adhered to the tongue dorsum markedly better than Neisseria, S. sanguis, and S. salivarius. The greater ability of Veillonella to adhere to the tongue in relation to the other organisms studied correlates with the high proportions of Veillonella found on this site. The feeble ability of Neisseria to attach to surfaces in the oral cavity is reflected by their low proportions found on these surfaces.