A 16S rRNA-based polymerase chain reaction (PCR) detection method was used to determine the prevalence of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermedia. Prevotella nigrescens and Treponema denticola in subgingival specimens of 50 advanced periodontitis, 50 adult gingivitis and 50 pediatric gingivitis subjects. The optimal PCR conditions were determined for each study species. Agarose gel electrophoresis of PCR products from each study species revealed a single band of the predicted size. Restriction enzyme digestion of amplicons confirmed the specificity of the amplification. PCR detection limits were in the range of 25-100 cells. No cross-reactivity with other oral micro-organisms or nonspecific amplification was observed. The prevalence by PCR in advanced periodontitis, adult gingivitis and pediatric gingivitis subjects was 30%, 14% and 14% for A. actinomycetemcomitans, 86%, 18% and 8% for B. forsythus, 74%, 52% and 78% for C. rectus, 80%, 70% and 66% for E. corrodens, 70%, 10% and 14% for P. gingivalis, 58%, 12% and 18% for P. intermedia, 52%, 20% and 22% for P. nigrescens, and 54%, 16% and 16% for T. denticola, respectively. The prevalence was higher in the advanced periodontitis group than in both adult gingivitis and pediatric gingivitis for A. actinomycetemcomitans, B. forsythus, P. gingivalis, P. intermedia, P. nigrescens and T. denticola at P < 0.01, and for E. corrodens at P < 0.05. The prevalence of C. rectus was significantly higher in the advanced periodontitis group than in the adult gingivitis group at P < 0.01. Matching results between PCR and culture occurred in 28% (B. forsythus) to 71% (A. actinomycetemcomitans) of the samples; the major discrepancy occurred in the PCR-positive/culture-negative category. Matching results between PCR and DNA probe methods were found in 84% of the subjects (B. forsythus) and 70% (P. gingivalis). Odds ratio analysis revealed statistically significant positive associations between 17 of the 28 possible combinations (P < 0.01). This study demonstrated the utility of a 16S rRNA-based PCR detection method for identifying important subgingival microorganisms. The results indicated a strong association between the study species and periodontitis. Several previously unreported symbiotic relationships were found between the 8 species tested.

The results indicate that subgingival EBV-1, HCMV, and viral coinfections are associated with the subgingival presence of some periodontal pathogens and periodontitis. Herpesviruses may exert periodontopathic potential by decreasing the host resistance against subgingival colonization and multiplication of periodontal pathogens.

The risk for harboring 6 putative periodontal pathogens in 4 selected periodontal pockets, in whole saliva, or in either site (i.e., orally) was determined in 52 Caucasians, 49 African‐Americans, 48 Asian‐Americans, and 50 Hispanics living in Los Angeles. 16S rRNA PCR analysis assessed the presence of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola. Step‐wise regression analysis determined the relationship between the occurrence of each organism and various explanatory variables (risk indicators). Periodontal probing depth or disease severity was positively associated with all 6 study organisms. African‐Americans carried an increased risk for harboring P. gingivalis in saliva (odds ratio [OR] 2.95) and orally (OR 2.66), and a reduced risk for harboring T. denticola orally (OR 0.34). Asian‐Americans showed an increased risk for harboring A. actinomycetemcomitans in periodontal pockets (OR 6.63) and P. gingivalis in periodontal pockets (OR 5.39), in saliva (OR 5.74), and orally (OR 5.81). Hispanics demonstrated an increased risk for harboring A. actinomycetemcomitans in periodontal pockets (OR 12.27) and P. gingivalis in periodontal pockets (OR 6.07), in saliva (OR 8.72), and orally (OR 7.98). Age was positively associated with the prevalence of P. gingivalis in saliva (OR 1.20) and orally (OR 1.20), and of A. actinomycetemcomitans orally (OR 1.18). The male gender was a risk factor for harboring P. intermedia in periodontal pockets (OR 2.40), in saliva (OR 3.31), and orally (OR 4.25), and for harboring P. nigrescens in saliva (OR 2.85). The longer the subjects resided in the United States, the less likely A. actinomycetemcomitans was detected orally (OR 0.82). Former smokers demonstrated a decreased risk for harboring A. actinomycetemcomitans in saliva (OR 0.23). Current smokers displayed an increased risk for harboring T. denticola in periodontal pockets (OR 4.61). The number of dental visits in the past 10 years was inversely related to the prevalence of P. intermedia orally (OR 0.96). The prevalence of P. intermedia in saliva was positively associated with the length of time from the last dental visit (OR 1.01). This study suggests that genetic and/or environmental factors predispose subjects to oral colonization by putative periodontal pathogens. J Periodontol 1998;69:1111–1118.

The utility of the 16S ribosomal RNA-based polymerase chain reaction (PCR) for detection of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola was examined and compared with that of anaerobic culture. Primer pairs consisting of 20-27 nucleotides amplified 404- to 688-bp regions of 16S ribosomal RNA genes of these organisms. This method had a lower detection limit of 50 target cells in a background of 10(7) cells. Its specificity for B. forsythus, P. gingivalis, and T. denticola seemed high. The primers for A. actinomycetemcomitans, C. rectus, and P. intermedia cross-reacted with some closely related species but did not reveal amplification products in tests with more distantly related organisms. The primers for E. corrodens did not seem to cross-react with oral organisms. This PCR technique was sensitive, reproducible, and easy to perform. PCR-based amplification may prove valuable for the detection of some periodontal pathogens in crude subgingival specimens.

This study examined the frequency of spouse-to-spouse and parent-child transmission of the periodontal pathogens Actinobacillus actinomycetemcomitans (124 subjects in 47 families) and Porphyromonas gingivalis (78 subjects in 31 families). The two test organisms were recovered from subgingival and tongue surface specimens using established microbiological techniques. Arbitrarily primed polymerase chain reaction (AP-PCR) was used to genetically characterize isolates of the test species. The probability of isolating identical AP-PCR types of A. actinomycetemcomitans and P. gingivalis in family members by chance was estimated from the AP-PCR genotype distribution of the two species among unrelated individuals. A probability of 5% or less for occurrence by chance alone suggests intra-familial transmission. With a bacterium-positive spouse, A. actinomycetemcomitans revealed inter-spousal transmission in 4/11 (36%) married couples and P. gingivalis in 2/10 (20%) married couples. Parent-child transmission of A. actinomycetemcomitans took place in 6/19 (32%) families. P. gingivalis was not transmitted from parent to child in any of the study families. The intra-familial transmission of A. actinomycetemcomitans and P. gingivalis may in part explain a familial pattern of periodontitis and may have important prophylactic and treatment implications.