Identification of periodontal pathogens in atheromatous plaques

Background: Recent studies suggest that chronic infections including those associated with periodontitis increase the risk for coronary vascular disea se (CVD) and stroke. We hypothesize that oral microorganisms including peri odontal bacterial pathogens enter the brood stream during transient bactere mias where they may play a role in the development and progression of ather osclerosis leading to CVD. Methods: To test this hypothesis, 50 human specimens obtained during caroti d endarterectomy were examined for the presence of Chlamydia pneumoniae, hu man cytomegalovirus, and bacterial 16S ribosomal RNA using specific oligonu cleotide primers in polymerase chain reaction (PCR) assays. Approximately 1 00 ng of chromosomal DNA was extracted from each specimen and then amplifie d using standard conditions (30 cycles of 30 seconds at 95 degreesC, 30 sec onds at 55 degreesC, and 30 seconds at 72 degreesC). Bacterial 16S rDNA was amplified using 2 synthetic oligonucleotide primers specific for eubacteri a. The PCR product generated with the eubacterial primers was transferred t o a charged nylon membrane and probed with digoxigenin-labeled synthetic ol igonucleotides specific for Actinobacillus actinomycetemcomitans, Bacteroid es forsythus, Porphyromonas gingivalis, and Prevotella intermedia. Results: Eighty percent of the 50 endarterectomy specimens were positive in 1 or more of the PCR assays. Thirty-eight percent were positive for HCMV a nd 18% percent were positive for C. pneumoniae. PCR assays for bacterial 16 S rDNA also indicated the presence of bacteria in 72% of the surgical speci mens. Subsequent hybridization of the bacterial 16S rDNA positive specimens with species-specific oligonucleotide probes revealed that 44% of the 50 a theromas were positive for at least one of the target periodontal pathogens . Thirty percent of the surgical specimens were positive for B. forsythus, 26% were positive for P. gingivalis, 18% were positive for A. actinomycetem comitans, and 14% were positive for P. intermedia. In the surgical specimen s positive for periodontal pathogens, more than I species was most often de tected. Thirteen (59%) of the 22 periodontal pathogen-positive surgical spe cimens were positive for 2 or more of the target species. Conclusions: Periodontal pathogens are present in atherosclerotic plaques w here, like other infectious microorganisms such as C. pneumoniae, they may play a role in the development and progression of atherosclerosis leading t o coronary vascular disease and other clinical sequelae.