Chronic dust bronchitis: composition of the sputum bacterial microbiome and its association with chromosome damage in blood lymphocytes

BACKGROUND: Recent studies show that the bacterial microbiome of the respiratory tract can influence the development of a number of diseases of the human respiratory system. Changes in the composition of the microbiome in patients are associated with dysbiosis, and in addition, many bacteria have a genotoxic potential and can directly or indirectly damage the genome in the cells of the host organism. 
AIM: The aim of the study was to analyze the composition of the sputum microbiome and its relationship with chromosome damage in the blood leukocytes of patients with chronic dust bronchitis (CDB). 
MATERIALS AND METHODS: The taxonomic composition of the sputum microbiome of 22 patients with CKD and 22 sputum donors from the control group was studied using next-generation sequencing (NGS) technology of 16S rRNA of bacterial genes. At the same time, the basic frequencies of chromosomal aberrations and micronuclei were determined in blood leukocytes. 
RESULTS: The sputum microbiome of chronic dust bronchitis patients had a significant reduction in alpha and beta diversity parameters compared to healthy study participants. In addition, an increase in the relative abundance of the genus Streptococcus (29.97 3.03 vs. 18.78 2.47; p = 0.003) was found in the sputum of CP patients compared with the control. Thus, the results of metagenome sequencing indicate a common dysbiotic process with a predominance of one dominant genus of bacteria in this pulmonary pathology. The results of cytogenetic analysis of blood leukocytes showed a significant increase in the proportion of aberrant metaphases in CKD patients compared with healthy donors (3.41% vs. 1.84%; p 0.01) and the absence of significant differences in frequency leukocytes with micronuclei between the compared groups (1.28% vs. 1.11%). Correlation analysis revealed the presence of significant direct relationships between the frequency of aberrant metaphases and the percentage of representatives of the genera Bacteroides in the sputum of patients with chronic dust bronchitis (r = 0.471; p = 0.031); Lachnoanaerobaculum (r = 0.446; p = 0.043) and Alloprevotella (r = 0.444; p = 0.044). Further studies should be devoted to the search for possible mechanisms of influence of these bacteria on clastogenic effects in the cells of the host organism.