Some Antagonistic Activity of Bacteria From the Human Oral Cavity

Abstract

2 saliva pools were used as source material. 1 pool was collected from caries-free persons and the other from individuals having 10 or more open carious lesions. A random sample of the bacteria contained in the saliva pools was obtained by using saline dilutions of 11, 1:10, 1:100 and 1:1000 for inoculations and aerobically incubating culture plates containing 13 types of media. 30 discernably different type bacterial colonies were found and established in pure culture. The antagonistic activity was tested, first, by the agar streak plate method with yeast dextrose agar using 3 strains of lactobacilli. 14 of the 30 showed some lactobacillus inhibition. Secondly, these 14, representing a variety of spp.,were tested for antagonistic activity against each other using the streak plate method. The number of other organisms each of these 14 inhibited, ranged from none to 12. The third and fourth tests, designed to test the antagonistic organism''s ability to prevent dentin tooth fragment wt. loss and Ca dissolution by lactobacillus in sucrose broth, were not effective in most instances.