The Distribution of Genus Enterococcus in Oral Cavity

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Enterococcus faecalis is a commonly found species in root canals. The study aim was to develop a new selective medium for the genus Enterococcus and clarify the distribution of the species in the oral cavity and to determine whether these enterococci were of endogenous or exogenous origin. The recovery rates of Enterococcus faecalis and Enterococcus faecium on a new selective medium were 89.3% and 88.5%, respectively. Dominant oral bacteria such as streptococci and neisseria did not grow on the medium. Enterococcus was detected from 5 in 12 subjects (ca. 42%) with low levels of 3 to 50 cfu/ml in their brushing samples. Only E. faecalis was detected in their samples, while E. faecium was not found. Genetic analysis using AP-PCR showed that the isolates from the oral cavity were not related to those from the fecal microflora. A few months after the first investigation, E. faecalis was confirmed to be maintained in the individual oral cavities of the same subjects by genetic analysis. The results indicated that E. faecalis isolated from the oral cavity was not derived from the subjects own normal microflora.