IDENTIFICATION OF BACTEROIDES-FORSYTHUS IN SUBGINGIVAL DENTAL PLAQUE WITH THE AID OF A RAPID PCR METHOD

Bacteroides forsythus has been shown to be prevalent among patients wi th periodontitis. Conventional microbiological methods used to identif y this bacterium, however, are laborious and time-consuming and are th erefore not well-suited for screening purposes. We have developed a po lymerase chain-reaction (PCR) method which is rapid, specific, and sim ple to perform and does not require other sample pre-treatment except a brief centrifugation. This method was applied to the detection of B. forsythus in subgingival plaque of 58 periodontitis patients. When co mpared with the results of conventional culturing, the PCR method alwa ys confirmed the culture-positive results, while none of the PCR negat ive samples was shown to be culture-positive. The PCR method appeared to give more than double the number of samples positive for B. forsyth us than culturing (89.7% vs. 37.9%). The analysis requires less than 4 hrs to perform, and is specific only to B. forsythus and sensitive en ough to detect fewer than 5 bacteria.