Detection of Streptococcus mutans by a fluorescent labeled oligonucleotide probe

Streptococcus mutans is the obligate colonizer of tooth surface and mucosal cells of humans. It involved in the formation of dental caries. A fast and reliable method for the rapid identification and quantification of Streptococcus mutans would be desirable and helpful for the risk evaluation and/or prevention of dental caries. Objectives: to develop a method to enumerate Streptococcus mutans in dental plaques by a fluorescent labeled oligonucleotide probe BC73. Methods:the Streptococcus mutans standard strains and samples of dental plaques were probed by the probes of EUB338 and BC73 using fluorescent in situ hybridization method. The fluorescent intensities and numbers were counted by flow cytometer. Results: the fluorescent intensity of Streptococcus mutans 10449 was 7 times higher than the fluorescent intensities of Streptococcus mitis 15914 and Escherichia coli K12 probed by probe BC73. There was 1.7% of Streptococcus mutans among the total bacteria number of dental plaque. Conclusion:the fluorescent labeled oligonucleotide probes BC73 could be used as a specific probe to detect Streptococcus mutans in the samples of dental plaques