Background: We recently reported that large amounts of oral bacterial DNA can be found in thrombus aspirates of myocardial infarction patients. Some case reports describe bacterial findings in pericardial fluid, mostly done with conventional culturing and a few with PCR; in purulent pericarditis, nevertheless, bacterial PCR has not been used as a diagnostic method before.

Objective: To find out whether bacterial DNA can be measured in the pericardial fluid and if it correlates with pathologic-anatomic findings linked to cardiovascular diseases.

Methods: Twenty-two pericardial aspirates were collected aseptically prior to forensic autopsy at Tampere University Hospital during 2009-2010. Of the autopsies, 10 (45.5%) were free of coronary artery disease (CAD), 7 (31.8%) had mild and 5 (22.7%) had severe CAD. Bacterial DNA amounts were determined using real-time quantitative PCR with specific primers and probes for all bacterial strains associated with endodontic disease (Streptococcus mitis group, Streptococcus anginosus group, Staphylococcus aureus/Staphylococcus epidermidis, Prevotella intermedia, Parvimonas micra) and periodontal disease (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Fusobacterium nucleatus, and Dialister pneumosintes).

Results: Of 22 cases, 14 (63.6%) were positive for endodontic and 8 (36.4%) for periodontal-disease-associated bacteria. Only one case was positive for bacterial culturing. There was a statistically significant association between the relative amount of bacterial DNA in the pericardial fluid and the severity of CAD (p=0.035).

Conclusions: Oral bacterial DNA was detectable in pericardial fluid and an association between the severity of CAD and the total amount of bacterial DNA in pericardial fluid was found, suggesting that this kind of measurement might be useful for clinical purposes.