Western Society of Periodontics

Laboratory Studies

Volume Number 4, 1995

Detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Bacteroides forsythus in an A. actinomycetemcomitans-positive patient population

The purpose of this study was to compare the relative sensitivity of indirect IF to culture or a DNA probe in identifying the presence of these target species. A total of 73 members of 25 families, each comprising at least one proband with localized juvenile periodontitis, were diagnosed as positive for A.a. The majority of these subjects did not have JP, although some of the adults had signs of adult periodontitis. The mesial surfaces of all natural teeth in each subject were lightly scaled and the harvested dental plaque pooled as a single sample in 0.5 ml of a transport medium consisting of a prereduced salt solution. Samples were processed by culturing and immunofluorescence as well as by DNA probe. A.a. was detected in 39.4% of samples, at a mean level of 0.64% of the cultivable counts. With IF, A.a. was detected in 81.8% of the samples, at levels of 0.40, 0.79, and 0.17% of the total counts for serotypes a, b, and c respectively. Overall, IF was more likely to detect A.a., P.g., and B.f. than any of the other methods. However, many of the levels of recovery were low. Thus the greater sensitivity of IF is seen as an advantage. [P.W.]