A BACTERIOLOGIC CENSUS OF HUMAN SALIVA

¹ Department of Bacteriology, College of Medicine, State University of Iowa, Iowa City, Iowa

A census of 14 bacterial groups has been obtained by cultural methods from unstimulated saliva of 14 adults. The saliva of each subject was examined on 10 separate occasions.

The group mean for the various categories may be expressed as high, intermediate, and low populations. High population means (n x 10⁶ per ml. saliva) were: total anaerobes 110, total aerobes 40, total streptococci 18,. Veillonella 17, S. salivarius 11, starch hydrolyzers 5, hydrogen sulfide-producers 2, and Neisseria 2. A total micrococcus population was estimated to be about that of the Neisseria. Intermediate population means (n x 10³ per ml. saliva) were: fusobacteria 56, lactobacilli 35, salt-tolerant micrococci 5, and Leptotrichia 3. Low populations (n x 10² per ml. saliva) were: Candida 2 and coliforms 1.

The Veillonella, total anaerobes and total aerobes were categories in which the least fluctuation occurred from examination to examination for all of the subjects.

No statistical differences were found between vegetarians and non-vegetarians for any of the categories.

Certain characteristics were identified with subjects exhibiting low counts as opposed to those exhibiting high counts. Thus, females had lower counts than males, slow spitters had lower counts than fast spitters, and nonsmokers or occasional smokers had lower counts than smokers.

Population counts of salt-tolerant micrococci, Neisseria, Leptotrichia, fusobacteria, and hydrogen sulfide-producers provided an index of gingival health. Subjects with statistically significant high counts in one or more of these categories had varying degrees of gingivitis and calculus deposits, whereas subjects with significantly low counts had clinically healthy gingiva and little or no calculus.