Background. Recent studies demonstrated a link between oral infections and the presence of atherosclerotic
lesions in carotid arteries. Periodontal pathogens, including Porphyromonas gingivalis, Prevotella intermedia,
Tannerella forsythia, Fusobacterium nucleatum, and Prevotella nigrescens have been identified in atherosclerotic
plaques. The microorganisms have been detected using PCR technique, DNA hybridization, FISH
analysis (fluorescence in situ hybridization), ELISA, by immunohistochemistry, and in transmission or scanning
electron microscopy. It is, however, only the FISH technique and culture in media that permit detection of
living microorganisms.
The aim of the study was to isolate anaerobic bacteria from atherosclerotic plaques from carotid arteries.

Materials and methods. Atherosclerotic plaques were obtained intraoperatively from 37 patients
(22 men and 15 women). The harvested plaques were placed in a transport medium prepared according to
the PRAS method. The material was then homogenized and cultured on various enriched or selective media.
Incubation was carried out for 10–14 days at 37°C, in anaerobic jars with 10% C02, 10% H2, and 80%
N2 atmosphere, with palladium catalyst and indicator of anaerobiosis. Anaerobic bacteria were identified
according to current regulations.

Results. Anaerobic bacteria were isolated from 68% of the analysed atherosclerotic plaques. Porphyromonas
gingivalis were the dominant species (20% of cases). Gram-positive rods Propionibacterium acnes
were identified in 18% of the samples, and Gram-negative rods Prevotella intermedia in 16% of plaques
from carotid arteries. Other anaerobic species, including Prevotella, Fusobacterium, Micromonas, Finegoldia,
Propionibacterium, and Actinomyces genus occurred in rare cases (2–8%).

Conclusions. Anaerobic bacteria were isolated from 68% of the atherosclerotic plaque samples obtained
from carotid arteries. The most prevalent Gram-negative rods included Porphyromonas gingivalis and Prevotella
intermedia species, and Gram-positive rods were most often represented by Propionibacterium acnes. Porphyromonas
endodontalis and Fusobacterium nucleatum species were isolated the least often.