Blood microbiome of patients with atherosclerosis

Aim of the study was to assess the composition of blood microbiome in patients with atherosclerosis, to compare it with microflora and microbiome of atherosclerotic plaques, to identify common taxons for microbiomes of blood and atherosclerotic plaques, as well as to perform a correlation analysis of various blood and urine parameters in the examined patients with the structure of «core» of the blood bacterial community. Material and methods. 19 men and 5 women aged 33–81 years (mean age 64.1 ± 9.8 years) with common carotid artery atherosclerosis confirmed by Doppler ultrasonography of vessels were examined. The microbial diversity of 24 blood samples from patients with vascular atherosclerosis was examined using 16S ribosomal RNA (16S rRNA) gene sequencing. 16 samples of atherosclerotic carotid artery plaques were examined by а bacteriological method. Correlation analysis of the results was performed by methods of nonparametric statistics. Results. Most of the sequences obtained were classified as Proteobacteria (73.9 %), Actinobacteria (11.4 %), Bacteroidetes (2.8 %), Cyanobacteria (1.3 %), Firmicutes (1.1 %), Fusobacteria (0.7 %). Genes of 16S rRNA of Propionibacterium acnes, undifferentiated species of the families Micrococcaceae, Caulobacteraceae, Bradyrhizobiaceae, genera Bradyrhizobium and Sphingomonas were found in all the examined blood samples of patients with atherosclerosis and comprised from 67.7 to 87.5 % of the microbial community taxons. 75 % of biopsy samples from atherosclerotic plaques showed growth of the bacteria: Propionibacterium acnes (43.8 %), Staphylococcus epidermidis (18.8 %), Staphylococcus capitis (6.3 %), Staphylococcus saccharolyticus (6.3 %). The common taxons for blood microbiomes and atherosclerotic plaques are Propionibacterium acnes and Bradyrhizobiaceae. Discussion. The present study is the first to report the blood microbiome of patients with atherosclerosis and to detect viable cultures of Propionibacterium acnes and Staphylococcus in biopsy samples of atherosclerotic plaques, providing a mechanistic link between microorganisms and cardiovascular disease. Propionibacterium acnes and Bradyrhizobiaceae are common taxons for blood microbiomes and atherosclerotic plaques. It can be assumed that Propionibacterium acnes species is a specific taxon both of atherosclerotic carotid artery plaques and blood of patients with carotid atherosclerosis; additional studies on the etiological significance of the microbial factor in the formation of atherosclerotic plaques are required

Blood microflora of patients with atherosclerotic vascular lesions and microflora of atherosclerotic plaques of carotid arteries

Aim of the study was to assess the frequency of microflora detection in the blood of patients with atherosclerotic vascular lesions and middle-aged patients without clinical symptoms of atherosclerosis. Compare the nature of microflora isolated from blood and the range of microorganisms isolated from atherosclerotic plaques (AP) of patients with carotid arteries atherosclerosis. Material and methods. The hemocultures of 118 men and 33 women with atherosclerosis (mean age 55.6 years) as well as 10 blood samples of 3 men and 7 women formed into a control group (mean age 37 years) were examined. Test samples were cultivated for 6 months. Tissue platings of carotid arteries AP in 11 women and 24 men of the main group (mean age 58.0) were incubated for 2 months. Methods based on Student’s t-test and Mann-Whitney U-test were used for statistical analysis of the obtained results. Results. Propionibacterium acnes hemocultures were detected in 9.9 % of patients from the main and control groups. In blood Staphylococcus epidermidis and Stenotrophomonas maltophylia were detected in 0.7 % of samples. P. acnes and Staphylococcus spp. cultures were obtained from AP in 34.3 and 45.7 %, including both microorganisms in 8.6 % of samples. Conclusions. P. acnes cultures are found equally frequently in the blood of atherosclerotic patients and patients not yet diagnosed with atherosclerosis. This study confirmed the presence of the same-name microorganisms in blood and atherosclerotic plaques. In 5.7 % (2 of 35) it was possible to extract simultaneously a P. acnes culture from two loci (atherosclerotic tissue and blood) in specific individuals. Further detailed research is required to study the etiological significance of the microbial factor in the atherosclerotic plaque formation

Bacterial Communities Associated with Atherosclerotic Plaques from Russian Individuals with Atherosclerosis.

Atherosclerosis is considered a chronic disease of the arterial wall and is the major cause of severe disease and death among individuals all over the world. Some recent studies have established the presence of bacteria in atherosclerotic plaque samples and suggested their possible contribution to the development of cardiovascular disease. The main objective of this preliminary pilot study was to better understand the bacterial diversity and abundance in human atherosclerotic plaques derived from common carotid arteries of individuals with atherosclerosis (Russian nationwide group) and contribute towards the further identification of a main group of atherosclerotic plaque bacteria by 454 pyrosequencing their 16S ribosomal RNA (16S rRNA) genes. The applied approach enabled the detection of bacterial DNA in all atherosclerotic plaques. We found that distinct members of the order Burkholderiales were present at high levels in all atherosclerotic plaques obtained from patients with atherosclerosis with the genus Curvibacter being predominant in all plaque samples. Moreover, unclassified Burkholderiales as well as members of the genera Propionibacterium and Ralstonia were typically the most significant taxa for all atherosclerotic plaques. Other genera such as Burkholderia, Corynebacterium and Sediminibacterium as well as unclassified Comamonadaceae, Oxalobacteraceae, Rhodospirillaceae, Bradyrhizobiaceae and Burkholderiaceae were always found but at low relative abundances of the total 16S rRNA gene population derived from all samples. Also, we found that some bacteria found in plaque samples correlated with some clinical parameters, including total cholesterol, alanine aminotransferase and fibrinogen levels. Finally, our study indicates that some bacterial agents at least partially may be involved in affecting the development of cardiovascular disease through different mechanisms

Bacterial community α diversity within atherosclerotic plaque samples.

<p>Bacterial community α diversity within atherosclerotic plaque samples.</p

Some characteristics of study individuals.

<p>Some characteristics of study individuals.</p

PCoA plots of the bacterial communities distribution in atherosclerotic plaque samples based on the data received by pyrosequencing of 16S rRNA gene fragments.

<p>(A) Unweighted Unifrac measurements. (B) Weighted Unifrac measurements (blue circles–men patients, red circles–women patients).</p

Bacteria associated with atherosclerotic plaque samples (mean values).

<p>Taxonomic classification of bacterial reads at (A) phylum level, (B) class level, (C) order level and (D) family level is demonstrated (data show more than 0.5%). Representatives accounting for less than 0.5% of all classified sequences are summarized in the group <i>“others”</i>.</p

Bacterial community α diversity within atherosclerotic plaque samples.

<p>Bacterial community α diversity within atherosclerotic plaque samples.</p