SULFATE-REDUCING BACTERIA IN THE PERIODONTAL POCKET

This report is the first to describe the occurrence of sulfate-reducin g bacteria in the human mouth. Samples of subgingival dental plaque we re examined for the presence of sulfate-reducing bacteria. Using enric hment cultures, sulfate-reducing bacteria were detected in 25 (58%) of 43 individuals, and in 39 (48%) of the 82 samples. Pure isolates of s ulfate-reducing bacteria, obtained from a limited number of enrichment cultures, belonged to the genera Desulfobacter and Desulfovibrio. The se genera are also the predominant sulfate-reducing bacteria in the hu man large intestine. The sulfate-reducing bacteria use sulfate as term inal electron acceptor to oxidize low-molecular-weight organic compoun ds, mainly products of microbial fermentation such as acetate, lactate etc. The numbers of sulfate-reducing bacteria in the mouth are assume d to be limited by sulfate. Potential sources of sulfate in the subgin gival area include free sulfate in pocket fluid and glycosaminoglycans from periodontal tissues.