DETECTION OF PORPHYROMONAS-GINGIVALIS IN ORAL PLAQUE SAMPLES BY USE OF THE POLYMERASE CHAIN-REACTION

Periodontitis is believed to be caused by bacteria which inhabit perio dontal pockets. The identification of these periodontal pathogens by c urrently available methods requires considerable time and expertise. I n this study, we have used a polymerase chain reaction (PCR) assay tha t is quick, relatively simple, and can detect low numbers of a putativ e periodontal pathogen. Primers specific for the fimbrial gene of Porp hyromonas gingivalis were selected from the published sequence and use d for amplification of a 131-basepair sequence of genomic DNA. The PCR detected as few as 100 P. gingivalis cells obtained from pure culture s. Three other bacteria (Actinobacillus actinomycetemcomitans, Prevote lla intermedia, and Capnocytophaga gingivalis) that are also putative periodontal pathogens yielded no PCR product at any of the cell concen trations used. This assay was also used for detection of P. gingivalis in subgingival plaque. Five of 13 subgingival bacterial plaque sample s obtained from four advanced adult periodontitis patients and two sam ples from a prepubescent child with advanced periodontitis contained P . gingivalis. The protocol developed is relatively simple and can be c ompleted within four hours of the time of sample acquisition.