Microflora of atherosclerotic plaques and blood of patients with atherosclerosis

Abstract

Background. Over the past decades, the role of the microbial factor in the development of atherosclerosis has been discussed. To date, data on the composition of the microflora of atherosclerotic plaques have been accumulated, but in these studies the blood microflora in atherosclerosis was not studied.
 Aim. To determine the contamination frequency of biopsy samples of atherosclerotic plaques and peripheral blood with cultured microorganisms in patients with atherosclerosis of the brachiocephalic arteries.
 Material and methods. A cross-sectional study in 35 patients with atherosclerosis of the carotid arteries; the average age of the patients was 58.2±8.3 years, was performed. Blood and atherosclerotic plaque samples from 23 men (mean age 58.6±10.3 years) and 12 women (mean age 57.3±14.3 years) were examined. Anaerobic flasks for blood cultivation were incubated at 35 °C for up to 6 months, from which they were regularly inoculated onto solid nutrient media to obtain culture growth. Cultures of tissues of atherosclerotic plaques of the carotid arteries in test tubes with thioglycollate medium were thermostated until visible growth of the culture was obtained; observation was carried out for up to 2 months. Identification of crops was carried out using commercial kits. For statistical analysis of the results obtained, the equality of the average values in two samples was checked using the Student’s statistical reliability test. Correlation analysis of the tightness of the connection was carried out using the Spearman rank correlation method.
 Results. The frequency of detection of microorganisms in samples of atherosclerotic plaques was 48.6% (17/35), including Cutibacterium acnes — in 31.4% (11/35), the genus Staphylococcus — in 22.9% (8/35), associations of these microorganisms — in 5.7% (2/35) of samples. C. acnes was cultured in the blood of 11.4% (4/35) of patients. In 5.7% (2/35) of patients, cultures of C. acnes bacteria were isolated from both atherosclerotic plaque biopsies and blood. Bacterial cultures exhibited slow growth on nutrient media. Correlation analysis of the closeness of the connection according to the Chaddock scale demonstrated the presence of a high and very high closeness of connection between the amount of high-density lipoproteins and the daily growth of C. acnes in atherosclerotic plaques (p=0.812) and blood (rxy=–0.969), the content of leukocytes showed a very high closeness of connection with days of growth of C. acnes in the blood (rxy=–0.957); Student's t-test revealed a statistically significant relationship with the fact of detection of C. acnes cultures in atherosclerotic plaques (p=0.013).
 Conclusion. Bacterial cultures isolated from blood samples and atherosclerotic plaques of patients with atherosclerosis had slow growth on nutrient media, and the period of their growth or the fact of detection correlated with the number of leukocytes and the level of high-density lipoproteins in the blood of patients.