Background: Chronic infections, such as periodontitis, have been associated with an increased risk for atherosclerosis and coronary artery disease. The aim of this study was to investigate biopsy samples of coronary and internal mammary arteries for the presence of putative pathogenic bacteria (Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Tannerella forsythensis), Chlamydia pneumoniae, and human cytomegalovirus (CMV).

Methods: Patients with a diagnosis of coronary artery disease were included in the study. Fifteen coronary arteries with atherosclerosis and 15 internal mammary arteries without clinically assessable atherosclerotic degeneration were investigated. Both groups of specimens were obtained during coronary artery bypass grafting surgery. In all cases, the coronary and mammary artery specimens were taken from the same patient. The detection of periodontal pathogens, C. pneumoniae, and CMV was done by polymerase chain reaction analysis.

Results: Bacterial DNA was found in nine of 15 (60%) coronary artery biopsy samples: P. gingivalis in eight (53.33%), A. actinomycetemcomitans in four (26.67%), P. intermedia in five (33.33%), and T. forsythensis in two (13.33%) samples; CMV was detected in 10 (66.67%) samples, and C. pneumoniae was detected in five (33.33%) samples. Some of the samples contained more than one type of bacteria. Periodontal pathogens were not detected in internal mammary artery biopsies, whereas CMV was present in seven (46.67%) samples and C. pneumoniae was present in six (40%) samples.

Conclusion: The absence of putative pathogenic bacteria in internal mammary arteries, which are known to be affected rarely by atherosclerotic changes, and their presence in a high percentage of atherosclerotic coronary arteries support the concept that periodontal organisms are associated with the development and progression of atherosclerosis.