Growth of Micro-organisms from Supragingival Dental Plaque on Saliva Agar

Abstract

The role of saliva in supporting the growth of dental plaque has scarcely been investigated. We have studied the growth and recovery of micro-organisms from dental plaque samples on saliva-agar plates, prepared from filter-sterilized wax-stimulated whole saliva. Under optimal conditions, the mean recovery of plaque samples on saliva agar was about 50% (range, 22-77) of the recovery on blood agar. Addition of 2.5 mmol/L dithiothreitol (DTT) strongly facilitated filter-sterilization of saliva, but DTT concentrations higher than 1 mmol/L reduced the recovery of plaque micro-organisms on saliva agar.

Catalase (100 U/ml) offered protection against the inhibitory effect of DTT. Addition of glucose (1-5 mmol/L) increased only slightly the recovery of plaque micro-organisms on saliva agar. When supragingival plaque was plated on saliva- and blood-agar plates, the composition of the microflora isolated from saliva agar strongly resembled that isolated from blood agar. The predominant species — i.e., Streptococcus and Actinomyces — all grew on saliva agar though usually in numbers somewhat lower than those on blood agar. In addition, most species normally found only in low proportions in supragingival dental plaque were also found to grow on saliva agar. Collectively, the results lead to the conclusion that the supragingival microflora can utilize saliva as a complete source of nutrients.

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References

Arglebe, C. (1981): Biochemistry of Human Saliva. In Sialadenosis and Sialadenitis, R. Chilla , Ed., Basel: S. Karger, pp. 97-234.

Beckers, H.J.A. and Van Der Hoeven, J.S. (1982): Growth Rates of Actinomyces viscosus and Streptococcus mutans during Early Colonization of Tooth Surfaces in Gnotobiotic Rats, Infect Immun 35:583-587.

Beckers, H.J.A. and Van Der Hoeven, J.S. (1984): The Effects of Mutual Interaction and Host Diet on the Growth Rates of the Bacteria Actinomyces viscosus and Streptococcus mutans during Colonization of Tooth Surfaces in Di-associated Gnotobiotic Rats, Arch Oral Biol 29:231-236:

Carlsson, J. ; Granberg, G.P.D. ; Nyberg, G.K. ; and Ed-Lund, M.B.K. (1979): Bactericidal Effect of Cysteine Exposed to Atmospheric Oxygen, Appl Environ Microbiol 37:383-390.

Carlsson, J. ; Iwami, Y. ; and Yamada, T. (1983): Hydrogen Peroxide Excretion by Oral Streptococci and Effect of Lactoperoxidase-Thiocyanate-Hydrogen Peroxide, Infect Immun 40:70-80.

Carlstedt, I. ; Lindgren, H. ; and Sheekan, J.H. (1983): The Macromolecular Structure of Human Cervical-mucus Glycoproteins, Biochem J 213:427-435.

Cowman, R.A. ; Fitzgerald, R.J. ; Perella, M.M. ; and Cornell, A.H. (1977a): Human Saliva as a Nitrogen Source for Oral Streptococci , Caries Res 11:1-8.

Cowman, R.A. ; Fitzgerald, R.J. ; and Schaefer, S.J. (1977b): Role of Salivary Factors in the Nitrogen Metabolism of Plaque-forming Oral Streptococci. In: Microbial Aspects of Dental Caries, III, H.M. Stiles , W.J. Loesche , and T.C. O'Brien. Eds., Sp. Supp., Microbiology Abstracts, Washington, D.C.: Information Retrieval, Ltd., pp. 433-464.

Cowman, R.A. ; Schaefer, S.J. ; and Fitzgerald, R.J. (1979): Specificity of Utilization of Human Salivary Proteins for Growth of Oral Streptococci, Caries Res 13:181-189.

10.

De Jong, M.H. ; Van Der Hoeven, J.S. ; Van Os, J.H. ; and Olijve, J.H. (1984): Growth of Oral Streptococcus Species and Actinomyces viscosus in Human Saliva, Appl Environ Microbiol 47:901-904.

11.

De Jong, M.H. ; Van Den Kieboom, C.W.A. ; Lukassen, J.A.M. ; and Van Der Hoeven, J.S. (1985): Effects of Dietary Carbohydrates on the Numbers of Streptococcus mutans and Actinomyces viscosus in Dental Plaque of Mono-infected Gnotobiotic Rats, J Dent Res 64:1134-1137.

12.

Holdeman, L.V. ; Cato, E.P. ; and Moore, W.E.C. (Eds.), (1977): Anaerobe Laboratory Manual, 4th ed. Blacksburg: Virginia Polytechnic Institute and State University Anaerobe Laboratory.

13.

Kleinberg, I. ; Kanapka, J.A. ; Chatterjee, R. ; Craw, D. ; Angelo, N.D. ; and Sandham, H.J. (1979): Metabolism of Nitrogen by the Oral Mixed Bacteria . In: Proceedings, Saliva and Dental Caries, I. Kleinberg , S.A. Ellison , and I.D. Mandel , Eds., Sp. Supp., Microbiology Abstracts, New York: Information Retrieval, Ltd., pp. 357-377.

14.

Klinkhamer, J.M. (1968): Saliva. In: Dental Biochemistry , E.P. Lazzari. Ed., Philadelphia: Lea and Febiger, pp. 122-142.

15.

Leach, S.A. (1964): Some Observations on the State of Sialic Acid in Human Saliva, Arch Oral Biol 9:461-467.

16.

Leach, S.A. (1965): Carbohydrates in Human Dental Plaque and Saliva . In: Advances in Fluorine Research and Dental Caries Prevention , J.L. Hardwick , H.R. Held , and K.G. Konig , Eds., Proceedings of the 11th ORCA, London: Pergamon Press, pp. 187-192.

17.

Leach, S.A. and Critchley, P. (1966): Bacterial Degradation of Glycoprotein Sugars in Human Saliva, Nature (London) 209:506.

18.

Leach, S.A. and Hayes, M.L. (1967): Isolation in Pure Culture of Human Oral Microorganisms Capable of Producing Neuraminidase, Nature (London) 216:599-560.

19.

Leach, S.A. and Melville, T.H. (1970): Investigation of Some Human Oral Organisms Capable of Releasing the Carbohydrates from Salivary Glycoproteins, Arch Oral Biol 15:87-88.

20.

Tatevossian, A. and Gould, C.T. (1976): The Composition of the Aqueous Phase in Human Dental Plaque, Arch Oral Biol 21 :319-323.

21.

Van Der Hoeven, J.S. ; De Jong, M.H. ; Rogers, A.H. ; and Camp, P.J.M. (1984): A Conceptual Model for the Co-existence of Streptococcus spp. and Actinomyces spp. in Dental Plaque, J Dent Res 63:389-392.