Sulfate-reducing bacteria in periodontal pockets and in healthy oral sites

The aim of this study was to monitor the presence of sulfate-reducing bacte ria (SRB) at different sites in the mouths of both healthy individuals and periodontitis patients. In 20 healthy subjects and 21 periodontitis patient s, samples were taken from the palate, vestibulum, dorsum of the tongue, su pragingival plaque, and periodontal pockets. In order to demonstrate growth of SRB, samples were incubated in an anoxic chamber in a reduced growth-me dium for SRB, with an iron-indicator for sulfide production. The SRB were d etected throughout the oral cavity. They were found on the mucosa in 10% of both healthy subjects and periodontitis patients. On the tongue and in sup ragingival plaque, the frequency of detection was slightly higher (22% of t he subjects). In contrast, 86% of the periodontitis patients harbored SRB i n one or more pockets. In 1/3 of the patients, SRB were present in all 3 po ckets that were sampled. The data indicated that SRB belong to the normal o ral microbiota, and have a preference for periodontal pockets.