Prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival microflora of Japanese patientswith adult and rapidly progressive periodontitis

Background, aims: This study investigated the prevalence of Bacteroides for sythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans a mong various periodontitis patients and healthy individuals in Japan, and c orrelated it with clinical parameters. Method: Subgingival plaque samples were collected from 21 patients with adu lt periodontitis (AP), 8 with rapidly progressive periodontitis (RPP) and 1 5 healthy individuals. Results: The frequency detected in culture was as follows: B. forsythus was found in 47.6% of AP sites and in 37.5% of RPP sites. P. gingivalis was id entified in 64.3% of AP and 59.4% of RPP sites. A. actinomycetemcomitans wa s detected in 4.8% of AP and 3.1% of RPP sites. The 3 species were detected in only 2 of the healthy individuals. The proportion of B. forsythus in th e total microflora in culture was 0.07% in the healthy group, 4.1% in AP an d 2.4% in RPP. The proportions of P. gingivalis were 0% in the healthy grou p, 18.8% in AP and 16.2% in RPP. The proportion of A. actinomycetemcomitans was very low in all 3 groups. A DNA probe detected B. forsythus in 78.6% o f AP and 65.6% of RPP sites, as well as P. gingivalis in 58.3% of AP and 59 .4% of RPP sites. A. aclinomycetemcomitans was detected in only 1.2% of AP sites. The 3 species were undetectable in the healthy group. Conclusions: The prevalence and the proportion of B. forsythus and P. gingi valis were significantly correlated with clinical parameters, suggesting th at B. forsythus and P. gingivalis are closely related to AP and RPP in the Japanese population.